Flame failure electrode question

Post by Tim Downie
My old White Knight gas tumble dryer played up the other day and I found
that the earth electrode (immediately above the main electrode) had eroded
and sagged until it was touching the central electrode. I bent it back and
all was well (briefly - but that's another story).
I thought I ought to order a new electrode but White Knight tell me that my
type (with integral earth electrode) has been superceded by one without an
earth electrode.
I'm sceptical that this will work in my machine (in the absence of an earth)
but I could be wrong.
Here's what mine looks like.
http://www.zen31010.zen.co.uk/images/ffe.jpg

Looks exactly like the ignition electrode in my Keston boiler.
They failed as the earth electrode drooped and the gap became too big
(it's mounted up the other way in the boiler's downward pointing burner).
They then modified them, and so far, the new type has been OK (I can't
remember what changed - I think the ceramic sleeve became longer, but
it still has the two electrodes).

I did repair the old ones a couple of times by bending the electrode
back, but this has to be done with it hot - if you try bending it cold
after it's had lots of heat treatment in the boiler, it's brittle and
usually snaps.

Post by Tim Downie
The replacement is just the same but without the "hockey stick" earth
electrode.
I'm waiting to hear from the technical adviser at the moment.
Should I just try it or is my scepticism justified?

Usually, the contact gap is resonably critical for proper ignition;
too small or big reduces chance of successful ignition (and too big
can also damage the spark coil). So it depends what the ground
electrode will be and how far away it is.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Tim

2011-09-09 14:59:52 UTC

Post by Andrew Gabriel

Looks exactly like the ignition electrode in my Keston boiler.
They failed as the earth electrode drooped and the gap became too big
(it's mounted up the other way in the boiler's downward pointing burner).
They then modified them, and so far, the new type has been OK (I can't
remember what changed - I think the ceramic sleeve became longer, but
it still has the two electrodes).
I did repair the old ones a couple of times by bending the electrode
back, but this has to be done with it hot - if you try bending it cold
after it's had lots of heat treatment in the boiler, it's brittle and
usually snaps.

It's not an ignition electrode, it's for flame sensing (hence subject!).

Tim

harry

2011-09-09 15:25:59 UTC

There will be two electrodes. One is for the spark ignitor. The other
is for detecting the flame. It does this by measuring the resistance
(the flame has low resistance compared with air.)
It's possible one electrode is used for both purposes. Or the two
electrodes may be identicle.
If it's old, it may have a different flame sensor which is a
thermocouple device. You can tell if it has this, there is a pilot
light.

Tim Downie

2011-09-09 18:56:45 UTC

Post by Tim Downie
My old White Knight gas tumble dryer played up the other day and I
found that the earth electrode (immediately above the main
electrode) had eroded and sagged until it was touching the central
electrode. I bent it back and all was well (briefly - but that's
another story).
I thought I ought to order a new electrode but White Knight tell me
that my type (with integral earth electrode) has been superceded by
one without an earth electrode.
I'm sceptical that this will work in my machine (in the absence of
an earth) but I could be wrong.
Here's what mine looks like.
http://www.zen31010.zen.co.uk/images/ffe.jpg
The replacement is just the same but without the "hockey stick" earth
electrode.
I'm waiting to hear from the technical adviser at the moment.
Should I just try it or is my scepticism justified?
Tim

There will be two electrodes.

Well yes, I know that.

Post by harry
One is for the spark ignitor. The other
is for detecting the flame. It does this by measuring the resistance
(the flame has low resistance compared with air.)
It's possible one electrode is used for both purposes.

Um no, not in this case. There is a seperate flame detector elctrode.

Post by harry
Or the two
electrodes may be identicle.
If it's old, it may have a different flame sensor which is a
thermocouple device. You can tell if it has this, there is a pilot
light.

Pilot light in a tumble dryer? I think not. ;-)

Anyway, for anyone who is interested, the technical bods from Crosslee have
been on the phone and tell me that as long as the tip is within 22mm of the
base of the burner, it will work without the earth electrode. Seems a
little odd given that the old gap was 1-2 mm. I'm not in a hurry to change
the electrode now though seeing as it's working.

Tim

harry

2011-09-10 05:53:32 UTC

Post by Tim Downie

Post by Tim Downie
My old White Knight gas tumble dryer played up the other day and I
found that the earth electrode (immediately above the main
electrode) had eroded and sagged until it was touching the central
electrode. I bent it back and all was well (briefly - but that's
another story).
I thought I ought to order a new electrode but White Knight tell me
that my type (with integral earth electrode) has been superceded by
one without an earth electrode.
I'm sceptical that this will work in my machine (in the absence of
an earth) but I could be wrong.
Here's what mine looks like.
http://www.zen31010.zen.co.uk/images/ffe.jpg
The replacement is just the same but without the "hockey stick" earth
electrode.
I'm waiting to hear from the technical adviser at the moment.
Should I just try it or is my scepticism justified?
Tim

There will be two electrodes.

Well yes, I know that.

Um no, not in this case. There is a seperate flame detector elctrode.

Post by harry
Or the two
electrodes may be identicle.
If it's old, it may have a different flame sensor which is a
thermocouple device. You can tell if it has this, there is a pilot
light.

Pilot light in a tumble dryer? I think not. ;-)
Anyway, for anyone who is interested, the technical bods from Crosslee have
been on the phone and tell me that as long as the tip is within 22mm of the
base of the burner, it will work without the earth electrode. Seems a
little odd given that the old gap was 1-2 mm. I'm not in a hurry to change
the electrode now though seeing as it's working.
Tim- Hide quoted text -
- Show quoted text -

Heh. No more dangerous than running a tumble dryer on gas in the first
place.

Tim

2011-09-10 07:19:19 UTC

On Sep 9, 7:56 pm, "Tim Downie"

Post by Tim Downie
Pilot light in a tumble dryer? I think not. ;-)
Anyway, for anyone who is interested, the technical bods from Crosslee have
been on the phone and tell me that as long as the tip is within 22mm of the
base of the burner, it will work without the earth electrode. Seems a
little odd given that the old gap was 1-2 mm. I'm not in a hurry to change
the electrode now though seeing as it's working.
Tim- Hide quoted text -
- Show quoted text -

Heh. No more dangerous than running a tumble dryer on gas in the first
place.

I'll bet many more house fires have been caused by electric dryers! ;-)

Seriously though, there are so many failsafes I doubt very much that a gas
dryer is any more dangerous than an electric one.

They certainly seem to be more durable. 21 years old and still going
strong.

Tim

Andrew Gabriel

2011-09-10 10:27:10 UTC

Post by Tim

On Sep 9, 7:56 pm, "Tim Downie"

Heh. No more dangerous than running a tumble dryer on gas in the first
place.

I'll bet many more house fires have been caused by electric dryers! ;-)
Seriously though, there are so many failsafes I doubt very much that a gas
dryer is any more dangerous than an electric one.
They certainly seem to be more durable. 21 years old and still going
strong.

My first experience with tumble driers was a gas one (in my university
hall of residence). Full washing load dry in 5 minutes (and that was
probably after a spin at no more than 500RPM in top loading washer).
Also used similar ones in the US more recently.
Just have to be careful to check no one's melted a pair of trainers
in them beforehand.

Electric ones were a tremendous disappointment when I first tried one.
That's why I've never owned one.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

m***@privacy.net

2011-09-10 15:27:30 UTC

On 10 Sep,

Post by Tim
I'll bet many more house fires have been caused by electric dryers! ;-)
Seriously though, there are so many failsafes I doubt very much that a gas
dryer is any more dangerous than an electric one.
They certainly seem to be more durable. 21 years old and still going
strong.

My first lasted about that long. (Support spider for drum failed, If I'd
known I could get one at the time it would have been repaired). It was
replaced by an almost identical one. Both White Knight.

Their service/spares dept is excellent in my experience.

--
B Thumbs
Change lycos to yahoo to reply

geoff

2011-09-18 22:04:09 UTC

In message

There will be two electrodes. One is for the spark ignitor. The other
is for detecting the flame. It does this by measuring the resistance
(the flame has low resistance compared with air.)

Good job I got back in time ...

No Harry, stick to your solar panels, you are completely wrong

It ABSOLUTELY doesn't measure the resistance, a flame acts like a lossy
rectifier and the flame sense circuit is looking for that rectification
effect in the flame - its a very safe way of flame detection since it
depends on a parameter that can't easily be duplicated in the way that a
resistance can

As long as the jet from which the gas issues is well earthed, then there
is a circuit when there is a flame (assuming that the sense electrode is
also in the flame)

Post by harry
It's possible one electrode is used for both purposes. Or the two
electrodes may be identicle.

But this isn't the case, is it? he said so

Post by harry
If it's old, it may have a different flame sensor which is a
thermocouple device.

No - he's shown the old one as a single electrode, not a junction

Post by harry
You can tell if it has this, there is a pilot
light.

Eejit

--
geoff

harry

2011-09-19 07:12:27 UTC

Post by geoff
In message

There will be two electrodes. One is for the spark ignitor. The other
is for detecting the flame. It does this by measuring the resistance
(the flame has low resistance compared with air.)

Good job I got back in time ...
No Harry, stick to your solar panels, you are completely wrong
It ABSOLUTELY doesn't measure the resistance, a flame acts like a lossy
rectifier and the flame sense circuit is looking for that rectification
effect in the flame - its a very safe way of flame detection since it
depends on a parameter that can't easily be duplicated in the way that a
resistance can
As long as the jet from which the gas issues is well earthed, then there
is a circuit when there is a flame (assuming that the sense electrode is
also in the flame)

It's possible one electrode is used for both purposes. Or the two
electrodes may be identicle.

But this isn't the case, is it? he said so

If it's old, it may have a different flame sensor which is a
thermocouple device.

No - he's shown the old one as a single electrode, not a junction

You can tell if it has this, there is a pilot
light.

Eejit
--
geoff- Hide quoted text -
- Show quoted text -

I wish you'd just piss off. I was repairing and running industrial
gas equipment for forty years.
http://en.wikipedia.org/wiki/Auto_reignition
http://en.wikipedia.org/wiki/Flame_detector#Ionisation_current_flame_detection

Chris K

2011-09-19 12:22:56 UTC

Post by geoff
In message

There will be two electrodes. One is for the spark ignitor. The other
is for detecting the flame. It does this by measuring the resistance
(the flame has low resistance compared with air.)

Good job I got back in time ...
No Harry, stick to your solar panels, you are completely wrong
It ABSOLUTELY doesn't measure the resistance, a flame acts like a lossy
rectifier and the flame sense circuit is looking for that rectification
effect in the flame - its a very safe way of flame detection since it
depends on a parameter that can't easily be duplicated in the way that a
resistance can
As long as the jet from which the gas issues is well earthed, then there
is a circuit when there is a flame (assuming that the sense electrode is
also in the flame)

Post by harry
It's possible one electrode is used for both purposes. Or the two
electrodes may be identicle.

But this isn't the case, is it? he said so

Post by harry
If it's old, it may have a different flame sensor which is a
thermocouple device.

No - he's shown the old one as a single electrode, not a junction

Post by harry
You can tell if it has this, there is a pilot
light.

Eejit
--
geoff- Hide quoted text -
- Show quoted text -

Maybe both systems are in use. Having just had to reverse engineer the
ignition circuitry on my boiler (Potterton Netaheat, circa 1987) I can
confirm it is flame rectification in this case sharing the electrode
with the spark ignition. 240v AC is injected into the flame from a
small capacitor from the mains live. The sensed voltage is fed through
a slow CR filter and used to turn on a transistor/bistable which flips
the relay that holds on the mains gas supply.

Until yesterday I thought it was simply testing the conductivity of the
flame but it is a bit cleverer than that - and fails safe whether the
sense electrode is O/c or shorted to ground.

BTW, problem was dried up electrolytics after being baked for 25 years:-)

Chris K

geoff

2011-09-19 20:02:35 UTC

Post by Chris K

Post by harry
I wish you'd just piss off. I was repairing and running industrial
gas equipment for forty years.
http://en.wikipedia.org/wiki/Auto_reignition
http://en.wikipedia.org/wiki/Flame_detector#Ionisation_current_flame_de
tection

Maybe both systems are in use.

Post by Chris K
Having just had to reverse engineer the ignition circuitry on my
boiler (Potterton Netaheat, circa 1987) I can confirm it is flame
rectification in this case sharing the electrode with the spark
ignition. 240v AC is injected into the flame from a small capacitor
from the mains live. The sensed voltage is fed through a slow CR
filter and used to turn on a transistor/bistable which flips the relay
that holds on the mains gas supply.

Yes, the circuit has changed little in principle since then

Post by Chris K
Until yesterday I thought it was simply testing the conductivity of the
flame but it is a bit cleverer than that - and fails safe whether the
sense electrode is O/c or shorted to ground.

As you say (as I mentioned yesterday) it's almost impossible to fool it
naturally

Post by Chris K
BTW, problem was dried up electrolytics after being baked for 25 years:-)
Chris K

--
geoff

geoff

2011-09-19 19:55:12 UTC

In message

Post by geoff
In message

There will be two electrodes. One is for the spark ignitor. The other
is for detecting the flame. It does this by measuring the resistance
(the flame has low resistance compared with air.)

Good job I got back in time ...
No Harry, stick to your solar panels, you are completely wrong
It ABSOLUTELY doesn't measure the resistance, a flame acts like a lossy
rectifier and the flame sense circuit is looking for that rectification
effect in the flame - its a very safe way of flame detection since it
depends on a parameter that can't easily be duplicated in the way that a
resistance can
As long as the jet from which the gas issues is well earthed, then there
is a circuit when there is a flame (assuming that the sense electrode is
also in the flame)

It's possible one electrode is used for both purposes. Or the two
electrodes may be identicle.

But this isn't the case, is it? he said so

If it's old, it may have a different flame sensor which is a
thermocouple device.

No - he's shown the old one as a single electrode, not a junction

You can tell if it has this, there is a pilot
light.

Eejit
--
geoff- Hide quoted text -
- Show quoted text -

I wish you'd just piss off. I was repairing and running industrial
gas equipment for forty years.

And you were prolly as incompetent then as you are now. I have vastly
more experience on modern domestic gas appliances than you do

It's not industrial gas equipment, is it - we're talking about modern
domestic gas appliances here. They don't use UV / IR , they rarely use
thermocouples (and if you had a clue, it would be obvious from the
sketch that it wasn't)

Post by harry
http://en.wikipedia.org/wiki/Auto_reignition
http://en.wikipedia.org/wiki/Flame_detector#Ionisation_current_flame_detection

This "One implementation of a gas burner with auto reignition senses the
electrical conductivity of the flame."

and this " There are also ionisation flame detectors, which use current
flow in the flame to detect flame presence, ... " while not incorrect,
are misleading and written by someone who doesn't understand the
process - I do

Flame sense electrodes (in modern domestic gas appliances) work on
detecting a rectification effect produced by the flame, they do NOT work
on resistance

for example

http://contractingbusiness.com/feature/cb_imp_13002/

"Flame rectification has become the primary means of flame sensing in
virtually all new residential and commercial gasfired HVAC equipment.
The days of the mercury filled autopilot and bimetal warp switch are
long gone. Be it an intermittent pilot system, direct spark ignition, or
a hot surface system, manufacturers have chosen flame rectification for
their means of flame verification.

Why flame rectification? It may be the safest form of flame sensing
available. It's virtually impossible to fool the ignition module with
anything short of an actual flame simulator. It's very fast, with no
cool down time such as with a thermocouple or autopilot. The gas flow
can be stopped almost instantaneously. Any sensing circuit failure will
result in a system shut down rather than an unsafe ignition."

So - you can piss off with your outdated and inaccurate claptrap. Half
of your input to the thread was wrong, the other half (thermocouples and
such) was just irrelevant

--
geoff

Tommy imp

2021-04-03 17:01:01 UTC

t may be the safest form of flame sensing available. It's virtually impossible to fool the ignition module with anything short of an actual flame simulato

Thx Geoff, helpful to a novice as a start point for reading up on this

--
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Tim+

2021-04-03 17:24:01 UTC

t may be the safest form of flame sensing available. It's virtually
impossible to fool the ignition module with anything short of an actual flame simulator

Thx Geoff, helpful to a novice as a start point for reading up on this.

You’re replying to a 9 year old message. FWIW the old White Knight is
still running...

Tim

--
Please don't feed the trolls

Stephen Howarth

2023-01-25 17:15:03 UTC

Hi, I don't know if this thread is still open but I have a problem with my White Knight Eco43A gas tumble dryer.
When it is switched on from cold, the gas comes on and ignites and runs for about 4 minutes in a clockwise direction. The gas then turns off, the drum reverses (anticlockwise) and then starts up again in the clockwise direction. The gas ignites but now only runs for about 8 seconds. It will continue to do this for the rest of the cycle until it finishes.
I have cleaned out all the air ducts, both inlet and exhaust thoroughly, the flexible exhaust pipe and outlet vent, inside is spotless.
I initially suspected the gas failure electrode but it will allow it to fire up for 4 minutes initially. Could this be failing once it got hot?
I have changed the inlet thermostats thinking that these could be the problem for a second hand pair from e bay. After fitting these, it did two cycles of 4 minute gas runs then went back to cutting off after 8 seconds on subsequent cycles.
Has anyone else encountered and solved this problem?
It's an old (but normally good) machine and I don't want to change it if there's a relatively cost effective fix.
My thoughts following the inlet stats were:-
1. Flame failure electrode
2. Exhaust Stats
3. Gas control unit
I was also struggling with sourcing parts, hence getting second hand stats from e bay. Is there anyone who keeps these bits or would have suitable replacements?
Thanks in advance

--
For full context, visit https://www.homeownershub.com/maintenance/cordless-power-tool-batteries-deteroriate-with-time-196739-.htm

Animal

2023-01-25 17:50:01 UTC

Post by Stephen Howarth
Hi, I don't know if this thread is still open but I have a problem with my White Knight Eco43A gas tumble dryer.
When it is switched on from cold, the gas comes on and ignites and runs for about 4 minutes in a clockwise direction. The gas then turns off, the drum reverses (anticlockwise) and then starts up again in the clockwise direction. The gas ignites but now only runs for about 8 seconds. It will continue to do this for the rest of the cycle until it finishes.
I have cleaned out all the air ducts, both inlet and exhaust thoroughly, the flexible exhaust pipe and outlet vent, inside is spotless.
I initially suspected the gas failure electrode but it will allow it to fire up for 4 minutes initially. Could this be failing once it got hot?
I have changed the inlet thermostats thinking that these could be the problem for a second hand pair from e bay. After fitting these, it did two cycles of 4 minute gas runs then went back to cutting off after 8 seconds on subsequent cycles.
Has anyone else encountered and solved this problem?
It's an old (but normally good) machine and I don't want to change it if there's a relatively cost effective fix.
My thoughts following the inlet stats were:-
1. Flame failure electrode
2. Exhaust Stats
3. Gas control unit
I was also struggling with sourcing parts, hence getting second hand stats from e bay. Is there anyone who keeps these bits or would have suitable replacements?
Thanks in advance.

If you can find a thead, it's open. Most people block the site you're posting from, you'll get far more feedback if you get here a saner way. Here is news:uk.d-i-y

Stephen Howarth

2023-01-25 18:17:28 UTC

If you can find a thead, it's open. Most people block the site you're posting from, you'll get far more feedback if you get here a saner way. Here is news:uk.d-i-y

Ok Animal, thank you. I'll post on here directly.

John Rumm

2023-01-25 18:39:17 UTC

If you can find a thead, it's open. Most people block the site you're posting from, you'll get far more feedback if you get here a saner way. Here is news:uk.d-i-y

Ok Animal, thank you. I'll post on here directly.

Infor on how:

http://wiki.diyfaq.org.uk/index.php/Newsgroup_access_tips
--
Cheers,

John.

/=================================================================\
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|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/

Brian Gaff

2023-01-26 09:30:25 UTC

What other gas devices do you have? This strange behaviour is eerily similar
to somebody in a nearby street where they had a water main burst. Water
somehow got into the gas pipe and the pressures were all over the place. I
believe British gas is now hoping to redo the area earlier than planned. The
soil is clay and most of the old pipes have gone rusty and the clay has
retained the gas until the upheaval of the water burst.
Brian
--
--:
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
***@blueyonder.co.uk
Blind user, so no pictures please
Note this Signature is meaningless.!

Post by Stephen Howarth
Hi, I don't know if this thread is still open but I have a problem with
my White Knight Eco43A gas tumble dryer.
When it is switched on from cold, the gas comes on and ignites and runs
for about 4 minutes in a clockwise direction. The gas then turns off,
the drum reverses (anticlockwise) and then starts up again in the
clockwise direction. The gas ignites but now only runs for about 8
seconds. It will continue to do this for the rest of the cycle until it
finishes.
I have cleaned out all the air ducts, both inlet and exhaust
thoroughly, the flexible exhaust pipe and outlet vent, inside is
spotless.
I initially suspected the gas failure electrode but it will allow it to
fire up for 4 minutes initially. Could this be failing once it got hot?
I have changed the inlet thermostats thinking that these could be the
problem for a second hand pair from e bay. After fitting these, it did
two cycles of 4 minute gas runs then went back to cutting off after 8
seconds on subsequent cycles.
Has anyone else encountered and solved this problem?
It's an old (but normally good) machine and I don't want to change it
if there's a relatively cost effective fix.
My thoughts following the inlet stats were:-
1. Flame failure electrode
2. Exhaust Stats
3. Gas control unit
I was also struggling with sourcing parts, hence getting second hand
stats from e bay. Is there anyone who keeps these bits or would have
suitable replacements?
Thanks in advance.

If you can find a thead, it's open. Most people block the site you're
posting from, you'll get far more feedback if you get here a saner way.
Here is news:uk.d-i-y

Ok Animal, thank you. I'll post on here directly.

http://wiki.diyfaq.org.uk/index.php/Newsgroup_access_tips
--
Cheers,
John.
/=================================================================\
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|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/

Stephen Howarth

2023-01-26 09:47:26 UTC

Post by Brian Gaff
What other gas devices do you have? This strange behaviour is eerily similar
to somebody in a nearby street where they had a water main burst. Water
somehow got into the gas pipe and the pressures were all over the place. I
believe British gas is now hoping to redo the area earlier than planned. The
soil is clay and most of the old pipes have gone rusty and the clay has
retained the gas until the upheaval of the water burst.
Brian
--
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
Blind user, so no pictures please
Note this Signature is meaningless.!

Post by Stephen Howarth
Hi, I don't know if this thread is still open but I have a problem with
my White Knight Eco43A gas tumble dryer.
When it is switched on from cold, the gas comes on and ignites and runs
for about 4 minutes in a clockwise direction. The gas then turns off,
the drum reverses (anticlockwise) and then starts up again in the
clockwise direction. The gas ignites but now only runs for about 8
seconds. It will continue to do this for the rest of the cycle until it
finishes.
I have cleaned out all the air ducts, both inlet and exhaust
thoroughly, the flexible exhaust pipe and outlet vent, inside is
spotless.
I initially suspected the gas failure electrode but it will allow it to
fire up for 4 minutes initially. Could this be failing once it got hot?
I have changed the inlet thermostats thinking that these could be the
problem for a second hand pair from e bay. After fitting these, it did
two cycles of 4 minute gas runs then went back to cutting off after 8
seconds on subsequent cycles.
Has anyone else encountered and solved this problem?
It's an old (but normally good) machine and I don't want to change it
if there's a relatively cost effective fix.
My thoughts following the inlet stats were:-
1. Flame failure electrode
2. Exhaust Stats
3. Gas control unit
I was also struggling with sourcing parts, hence getting second hand
stats from e bay. Is there anyone who keeps these bits or would have
suitable replacements?
Thanks in advance.

If you can find a thead, it's open. Most people block the site you're
posting from, you'll get far more feedback if you get here a saner way.
Here is news:uk.d-i-y

Ok Animal, thank you. I'll post on here directly.

Thanks for your replies gents,
Tim, I'll have a go at cleaning the electrode this morning and continue my search for one.
Brian, I have a gas boiler which is working fine. I have heard of people getting water in gas appliances but I don't think this is the problem in my case. Thank you for the suggestion though.

Stephen Howarth

2023-01-26 20:41:36 UTC

Post by Stephen Howarth
Hi, I don't know if this thread is still open but I have a problem with
my White Knight Eco43A gas tumble dryer.
When it is switched on from cold, the gas comes on and ignites and runs
for about 4 minutes in a clockwise direction. The gas then turns off,
the drum reverses (anticlockwise) and then starts up again in the
clockwise direction. The gas ignites but now only runs for about 8
seconds. It will continue to do this for the rest of the cycle until it
finishes.
I have cleaned out all the air ducts, both inlet and exhaust
thoroughly, the flexible exhaust pipe and outlet vent, inside is
spotless.
I initially suspected the gas failure electrode but it will allow it to
fire up for 4 minutes initially. Could this be failing once it got hot?
I have changed the inlet thermostats thinking that these could be the
problem for a second hand pair from e bay. After fitting these, it did
two cycles of 4 minute gas runs then went back to cutting off after 8
seconds on subsequent cycles.
Has anyone else encountered and solved this problem?
It's an old (but normally good) machine and I don't want to change it
if there's a relatively cost effective fix.
My thoughts following the inlet stats were:-
1. Flame failure electrode
2. Exhaust Stats
3. Gas control unit
I was also struggling with sourcing parts, hence getting second hand
stats from e bay. Is there anyone who keeps these bits or would have
suitable replacements?
Thanks in advance.

If you can find a thead, it's open. Most people block the site you're
posting from, you'll get far more feedback if you get here a saner way.
Here is news:uk.d-i-y

Ok Animal, thank you. I'll post on here directly.

Update on the tumble dryer.
I cleaned the flame failure electrode this morning with a piece of fine wet and dry. It didn't appear to be damaged or corroded.
The dryer did two cycles with full 4 minute gas burns but on subsequent cycles went back to 8 second burns.
(It did the same following my changing the inlet stats) Annoying as I thought I'd sorted it.
It has now gone back to doing a single 4 minute burn then only 8 seconds.
I'm assuming that whatever the faulty part is, it is failing once it gets hot.
Would a flame failure electrode behave like this? Thermocouples which I've changed in the past either work or they don't but I have no experience with electrodes.
Any further suggestions would be welcome
Thank you.

Tim+

2023-01-26 21:45:23 UTC

Post by Stephen Howarth
Hi, I don't know if this thread is still open but I have a problem with
my White Knight Eco43A gas tumble dryer.
When it is switched on from cold, the gas comes on and ignites and runs
for about 4 minutes in a clockwise direction. The gas then turns off,
the drum reverses (anticlockwise) and then starts up again in the
clockwise direction. The gas ignites but now only runs for about 8
seconds. It will continue to do this for the rest of the cycle until it
finishes.
I have cleaned out all the air ducts, both inlet and exhaust
thoroughly, the flexible exhaust pipe and outlet vent, inside is
spotless.
I initially suspected the gas failure electrode but it will allow it to
fire up for 4 minutes initially. Could this be failing once it got hot?
I have changed the inlet thermostats thinking that these could be the
problem for a second hand pair from e bay. After fitting these, it did
two cycles of 4 minute gas runs then went back to cutting off after 8
seconds on subsequent cycles.
Has anyone else encountered and solved this problem?
It's an old (but normally good) machine and I don't want to change it
if there's a relatively cost effective fix.
My thoughts following the inlet stats were:-
1. Flame failure electrode
2. Exhaust Stats
3. Gas control unit
I was also struggling with sourcing parts, hence getting second hand
stats from e bay. Is there anyone who keeps these bits or would have
suitable replacements?
Thanks in advance.

If you can find a thead, it's open. Most people block the site you're
posting from, you'll get far more feedback if you get here a saner way.
Here is news:uk.d-i-y

Ok Animal, thank you. I'll post on here directly.

Thanks for your replies gents,
Tim, I'll have a go at cleaning the electrode this morning and continue
my search for one.
Brian, I have a gas boiler which is working fine.
I have heard of people getting water in gas appliances but I don't think
this is the problem in my case. Thank you for the suggestion though.

Update on the tumble dryer.
I cleaned the flame failure electrode this morning with a piece of fine
wet and dry. It didn't appear to be damaged or corroded.
The dryer did two cycles with full 4 minute gas burns but on subsequent
cycles went back to 8 second burns.
(It did the same following my changing the inlet stats) Annoying as I
thought I'd sorted it.
It has now gone back to doing a single 4 minute
burn then only 8 seconds.
I'm assuming that whatever the faulty part is, it is failing once it gets hot.
Would a flame failure electrode behave like this? Thermocouples which
I've changed in the past either work or they don't but I have no
experience with electrodes.
Any further suggestions would be welcome
Thank you.

Any evidence of insulation breakdown or damage to the lead that connects
the flame detector? (Just floating an idea).

I wonder if it would be worth opening up the main control box and looking
for swollen/leaking capacitors (assuming it’s not potted)? Don’t think you
have much to lose.

Tim

--
Please don't feed the trolls

alan_m

2023-01-26 21:59:02 UTC

Post by Tim+
I wonder if it would be worth opening up the main control box and looking
for swollen/leaking capacitors (assuming it’s not potted)? Don’t think you
have much to lose.
Tim

Could it be the body of the component is the electrical return path and
there is corrosion on a screw thread on the fitting?

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

Tim+

2023-01-27 13:56:20 UTC

Post by Stephen Howarth
Any further suggestions would be welcome
Thank you.

FWIW, I opened my control box today. It’s easy to get at the bottom of the
circuit board but alas the HV igniter is potted into a recess in the top
cover. Just makes it a bit more of a faff to look inside as you need to
desolder the connections to the igniter. I’d assume that your is similar.

Tim

--
Please don't feed the trolls

Tim+

2023-01-27 14:19:27 UTC

Post by Stephen Howarth
Any further suggestions would be welcome
Thank you.

This might interest you Stephen.

I got my control box open. Mine looks like this.
https://photos.app.goo.gl/mfUkoY8GSPXqN7Bc9

Inside, there was an oily slick on one side of the circuit board centred
around one capacitor which has clearly leaked.

https://photos.app.goo.gl/9JudriBTVJQupPrM9

The writing on the side of the capacitor is 20uF, 63V, (SA) 85°C, 8852M

https://photos.app.goo.gl/zgRwhrXQgxDuV2FX6

If yours looks like mine it would definitely be worth trying replacing the
capacitor. The desoldering to get access to the control board was quite
easy (just three wires).

Tim

--
Please don't feed the trolls

alan_m

2023-01-27 15:40:38 UTC

Post by Stephen Howarth
Any further suggestions would be welcome
Thank you.

This might interest you Stephen.
I got my control box open. Mine looks like this.
https://photos.app.goo.gl/mfUkoY8GSPXqN7Bc9
Inside, there was an oily slick on one side of the circuit board centred
around one capacitor which has clearly leaked.
https://photos.app.goo.gl/9JudriBTVJQupPrM9
The writing on the side of the capacitor is 20uF, 63V, (SA) 85°C, 8852M
https://photos.app.goo.gl/zgRwhrXQgxDuV2FX6
If yours looks like mine it would definitely be worth trying replacing the
capacitor. The desoldering to get access to the control board was quite
easy (just three wires).
Tim

C5 on that board also appeared to have failed - it looks as if it is
bulging at the top.
https://www.robotroom.com/Faulty-Capacitors-1.html

When replacing capacitors get one rated at 105C rather than one rated at
85C.
22uF is a more common value and this higher value would be a suitable
replacement for "20uF, 63V, (SA) 85°C, 8852M"

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

John Rumm

2023-01-27 16:28:09 UTC

Update on the tumble dryer. I cleaned the flame failure electrode
this morning with a piece of fine wet and dry. It didn't appear to be
damaged or corroded. The dryer did two cycles with full 4 minute gas
burns but on subsequent cycles went back to 8 second burns. (It did
the same following my changing the inlet stats) Annoying as I thought
I'd sorted it. It has now gone back to doing a single 4 minute burn
then only 8 seconds. I'm assuming that whatever the faulty part is,
it is failing once it gets hot. Would a flame failure electrode
behave like this?

I had a failure like this in old Ideal Mexico floor standing boiler. It
would power up and run for a bit then the flame would cut out - it would
then periodically restart, run a few a few seconds and stop again.

It turned out to be the gas valve - it basically would not stay open
when hot.

Thermocouples which I've changed in the past either
work or they don't but I have no experience with electrodes. Any
further suggestions would be welcome Thank you.

With the boiler it was easy to diagnose with a multimeter. I looked at
the mains input into the valve. I could see the demand appear when the
programmer/stat was calling for heat, and it remained there even when
the valve shut off - indicating that the valve was not doing one thing
it is required to do! By looking at the input of the valve you can
eliminate all the other bits like internal stats, or control system
problems.
--
Cheers,

John.

/=================================================================\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/

Tim+

2023-01-27 16:39:10 UTC

Update on the tumble dryer. I cleaned the flame failure electrode
this morning with a piece of fine wet and dry. It didn't appear to be
damaged or corroded. The dryer did two cycles with full 4 minute gas
burns but on subsequent cycles went back to 8 second burns. (It did
the same following my changing the inlet stats) Annoying as I thought
I'd sorted it. It has now gone back to doing a single 4 minute burn
then only 8 seconds. I'm assuming that whatever the faulty part is,
it is failing once it gets hot. Would a flame failure electrode
behave like this?

I had a failure like this in old Ideal Mexico floor standing boiler. It
would power up and run for a bit then the flame would cut out - it would
then periodically restart, run a few a few seconds and stop again.
It turned out to be the gas valve - it basically would not stay open
when hot.

Thermocouples which I've changed in the past either
work or they don't but I have no experience with electrodes. Any
further suggestions would be welcome Thank you.

It did cross my mind that it could be the gas valves but the 8 second burn
time is significant as that’s more or less the nominal ignition time for
the control board. A failing gas valve that would flow gas for a fixed
period regularly would be an odd fault.

https://photos.app.goo.gl/mfUkoY8GSPXqN7Bc9

This suggests to me that it is a flame sensing issue and having looked
inside my old control box, I’d be willing to bet that Stephen has similarly
knackered capacitors.

Tim

--
Please don't feed the trolls

Stephen Howarth

2023-01-27 20:18:25 UTC

Update on the tumble dryer. I cleaned the flame failure electrode
this morning with a piece of fine wet and dry. It didn't appear to be
damaged or corroded. The dryer did two cycles with full 4 minute gas
burns but on subsequent cycles went back to 8 second burns. (It did
the same following my changing the inlet stats) Annoying as I thought
I'd sorted it. It has now gone back to doing a single 4 minute burn
then only 8 seconds. I'm assuming that whatever the faulty part is,
it is failing once it gets hot. Would a flame failure electrode
behave like this?

I had a failure like this in old Ideal Mexico floor standing boiler. It
would power up and run for a bit then the flame would cut out - it would
then periodically restart, run a few a few seconds and stop again.
It turned out to be the gas valve - it basically would not stay open
when hot.

Thermocouples which I've changed in the past either
work or they don't but I have no experience with electrodes. Any
further suggestions would be welcome Thank you.

It did cross my mind that it could be the gas valves but the 8 second burn
time is significant as that’s more or less the nominal ignition time for
the control board. A failing gas valve that would flow gas for a fixed
period regularly would be an odd fault.
https://photos.app.goo.gl/mfUkoY8GSPXqN7Bc9
This suggests to me that it is a flame sensing issue and having looked
inside my old control box, I’d be willing to bet that Stephen has similarly
knackered capacitors.
Tim
--
Please don't feed the trolls

Stephen Howarth

2023-01-27 21:52:28 UTC

Update on the tumble dryer. I cleaned the flame failure electrode
this morning with a piece of fine wet and dry. It didn't appear to be
damaged or corroded. The dryer did two cycles with full 4 minute gas
burns but on subsequent cycles went back to 8 second burns. (It did
the same following my changing the inlet stats) Annoying as I thought
I'd sorted it. It has now gone back to doing a single 4 minute burn
then only 8 seconds. I'm assuming that whatever the faulty part is,
it is failing once it gets hot. Would a flame failure electrode
behave like this?

I had a failure like this in old Ideal Mexico floor standing boiler. It
would power up and run for a bit then the flame would cut out - it would
then periodically restart, run a few a few seconds and stop again.
It turned out to be the gas valve - it basically would not stay open
when hot.

Thermocouples which I've changed in the past either
work or they don't but I have no experience with electrodes. Any
further suggestions would be welcome Thank you.

It did cross my mind that it could be the gas valves but the 8 second burn
time is significant as that’s more or less the nominal ignition time for
the control board. A failing gas valve that would flow gas for a fixed
period regularly would be an odd fault.
https://photos.app.goo.gl/mfUkoY8GSPXqN7Bc9
This suggests to me that it is a flame sensing issue and having looked
inside my old control box, I’d be willing to bet that Stephen has similarly
knackered capacitors.
Tim
--
Please don't feed the trolls

Thank you gents for all your suggestions.
Tim, I have open the control box which is different to yours, and to my untrained eye, there's nothing obviously amiss, no leaking or puffed up capacitors or staining. Nothing obvious showing on the soldered side. I'm aware that this isn't definitive.
https://photos.app.goo.gl/mtFgmtBgSzVCETSz6
https://photos.app.goo.gl/fK3bS6rXtscZQqrSA
All the electrical surfaces on the flame sensing electrode are clean and polished.
I've tested the earth continuity between the burner tube where the electrode fixes and the earth pin on the plug which is good.
There is continuity between the flame sensor spade connecter and where it goes into the control unit.
John, the gas valves are in a very inaccessible place and would be virtually impossible to test whilst the machine was running.
Thank you all again for your help, hopefully between us , we'll get to the cause!

Animal

2023-01-27 23:54:18 UTC

Update on the tumble dryer. I cleaned the flame failure electrode
this morning with a piece of fine wet and dry. It didn't appear to be
damaged or corroded. The dryer did two cycles with full 4 minute gas
burns but on subsequent cycles went back to 8 second burns. (It did
the same following my changing the inlet stats) Annoying as I thought
I'd sorted it. It has now gone back to doing a single 4 minute burn
then only 8 seconds. I'm assuming that whatever the faulty part is,
it is failing once it gets hot. Would a flame failure electrode
behave like this?

I had a failure like this in old Ideal Mexico floor standing boiler. It
would power up and run for a bit then the flame would cut out - it would
then periodically restart, run a few a few seconds and stop again.
It turned out to be the gas valve - it basically would not stay open
when hot.

Thermocouples which I've changed in the past either
work or they don't but I have no experience with electrodes. Any
further suggestions would be welcome Thank you.

It did cross my mind that it could be the gas valves but the 8 second burn
time is significant as that’s more or less the nominal ignition time for
the control board. A failing gas valve that would flow gas for a fixed
period regularly would be an odd fault.
https://photos.app.goo.gl/mfUkoY8GSPXqN7Bc9
This suggests to me that it is a flame sensing issue and having looked
inside my old control box, I’d be willing to bet that Stephen has similarly
knackered capacitors.
Tim
--
Please don't feed the trolls

Most failed caps look fine. A component tester would check them after unsoldering. Bad joints are another thing you can look for, eg cracked solder.

Tim+

2023-01-28 09:08:16 UTC

Update on the tumble dryer. I cleaned the flame failure electrode
this morning with a piece of fine wet and dry. It didn't appear to be
damaged or corroded. The dryer did two cycles with full 4 minute gas
burns but on subsequent cycles went back to 8 second burns. (It did
the same following my changing the inlet stats) Annoying as I thought
I'd sorted it. It has now gone back to doing a single 4 minute burn
then only 8 seconds. I'm assuming that whatever the faulty part is,
it is failing once it gets hot. Would a flame failure electrode
behave like this?

I had a failure like this in old Ideal Mexico floor standing boiler. It
would power up and run for a bit then the flame would cut out - it would
then periodically restart, run a few a few seconds and stop again.
It turned out to be the gas valve - it basically would not stay open
when hot.

Thermocouples which I've changed in the past either
work or they don't but I have no experience with electrodes. Any
further suggestions would be welcome Thank you.

It did cross my mind that it could be the gas valves but the 8 second burn
time is significant as that’s more or less the nominal ignition time for
the control board. A failing gas valve that would flow gas for a fixed
period regularly would be an odd fault.
https://photos.app.goo.gl/mfUkoY8GSPXqN7Bc9
This suggests to me that it is a flame sensing issue and having looked
inside my old control box, I’d be willing to bet that Stephen has similarly
knackered capacitors.
Tim
--
Please don't feed the trolls

Thank you gents for all your suggestions.
Tim, I have open the control box which is different to yours, and to my
untrained eye, there's nothing obviously amiss, no leaking or puffed up
capacitors or staining. Nothing obvious showing on the soldered side.
I'm aware that this isn't definitive.
https://photos.app.goo.gl/mtFgmtBgSzVCETSz6
https://photos.app.goo.gl/fK3bS6rXtscZQqrSA
All the electrical surfaces on the flame sensing electrode are clean and polished.
I've tested the earth continuity between the burner tube where the
electrode fixes and the earth pin on the plug which is good.
There is continuity between the flame sensor spade connecter and where it
goes into the control unit.
John, the gas valves are in a very inaccessible place and would be
virtually impossible to test whilst the machine was running.
Thank you all again for your help, hopefully between us , we'll get to the cause!

After all my deductive reasoning I consider it very unreasonable for your
circuit board not to be obviously faulty! ;-)

I’m gonna stick to my guns and say that it’s just inconspicuously faulty
now.

Tim

--
Please don't feed the trolls

Stephen Howarth

2023-01-28 09:50:53 UTC

Update on the tumble dryer. I cleaned the flame failure electrode
this morning with a piece of fine wet and dry. It didn't appear to be
damaged or corroded. The dryer did two cycles with full 4 minute gas
burns but on subsequent cycles went back to 8 second burns. (It did
the same following my changing the inlet stats) Annoying as I thought
I'd sorted it. It has now gone back to doing a single 4 minute burn
then only 8 seconds. I'm assuming that whatever the faulty part is,
it is failing once it gets hot. Would a flame failure electrode
behave like this?

I had a failure like this in old Ideal Mexico floor standing boiler. It
would power up and run for a bit then the flame would cut out - it would
then periodically restart, run a few a few seconds and stop again.
It turned out to be the gas valve - it basically would not stay open
when hot.

Thermocouples which I've changed in the past either
work or they don't but I have no experience with electrodes. Any
further suggestions would be welcome Thank you.

It did cross my mind that it could be the gas valves but the 8 second burn
time is significant as that’s more or less the nominal ignition time for
the control board. A failing gas valve that would flow gas for a fixed
period regularly would be an odd fault.
https://photos.app.goo.gl/mfUkoY8GSPXqN7Bc9
This suggests to me that it is a flame sensing issue and having looked
inside my old control box, I’d be willing to bet that Stephen has similarly
knackered capacitors.
Tim
--
Please don't feed the trolls

Thank you gents for all your suggestions.
Tim, I have open the control box which is different to yours, and to my
untrained eye, there's nothing obviously amiss, no leaking or puffed up
capacitors or staining. Nothing obvious showing on the soldered side.
I'm aware that this isn't definitive.
https://photos.app.goo.gl/mtFgmtBgSzVCETSz6
https://photos.app.goo.gl/fK3bS6rXtscZQqrSA
All the electrical surfaces on the flame sensing electrode are clean and polished.
I've tested the earth continuity between the burner tube where the
electrode fixes and the earth pin on the plug which is good.
There is continuity between the flame sensor spade connecter and where it
goes into the control unit.
John, the gas valves are in a very inaccessible place and would be
virtually impossible to test whilst the machine was running.
Thank you all again for your help, hopefully between us , we'll get to the cause!

After all my deductive reasoning I consider it very unreasonable for your
circuit board not to be obviously faulty! ;-)
I’m gonna stick to my guns and say that it’s just inconspicuously faulty
now.
Tim
--
Please don't feed the trolls

It could well be the circuit board Tim/Animal.
If that's the case, it's probably not worth the expense of replacing it (if I could find one) and it'd be beyond my capability of repairing it.
My wife is chomping at the bit to go and buy a new one. I just don't like being beaten by a fault which as you say, probably something minor.
Thanks to everyone for your suggestions and help. Steve.

Tim+

2023-01-28 11:25:58 UTC

Post by Stephen Howarth
It could well be the circuit board Tim/Animal.
If that's the case, it's probably not worth the expense of replacing it
(if I could find one) and it'd be beyond my capability of repairing it.
My wife is chomping at the bit to go and buy a new one. I just don't like
being beaten by a fault which as you say, probably something minor.
Thanks to everyone for your suggestions and help. Steve.

That’s a shame but you’ve probably had your money’s worth out of your
dryer. I was sad to retire mine after 33 years. If the heat pump
replacement lasts 33 years I shall be very surprised (and 99 years old!).

--
Please don't feed the trolls

Tim Lamb

2023-01-28 12:29:08 UTC

In message <23e4cfe4-84c5-4e25-90d0-***@googlegroups.com>,
Stephen Howarth <***@gmail.com> writes
snip.

Post by Tim+
After all my deductive reasoning I consider it very unreasonable for your
circuit board not to be obviously faulty! ;-)
I’m gonna stick to my guns and say that it’s just inconspicuously faulty
now.
Tim
--
Please don't feed the trolls

It could well be the circuit board Tim/Animal.
If that's the case, it's probably not worth the expense of replacing it
(if I could find one) and it'd be beyond my capability of repairing it.
My wife is chomping at the bit to go and buy a new one. I just don't
like being beaten by a fault which as you say, probably something minor.
Thanks to everyone for your suggestions and help. Steve.

Steve. My very limited involvement in circuit board soldering
failure/dry joints suggests you check carefully where *thermally
massive* components are attached.

Assembly may well have moved along from the *solder bath* technique
where a wave of molten solder washes over the back of the assembled
board, but, localised *chilling* can lead to poor quality connections.

--
Tim Lamb

The Natural Philosopher

2023-01-28 13:19:00 UTC

Post by Tim Lamb
snip.

It could well be the circuit board Tim/Animal.
If that's the case, it's probably not worth the expense of replacing
it (if I could find one) and it'd be beyond my capability of repairing
it.
My wife is chomping at the bit to go and buy a new one. I just don't
like being beaten by a fault which as you say, probably something minor.
Thanks to everyone for your suggestions and help. Steve.

Steve. My very limited involvement in circuit board soldering
failure/dry joints suggests you check carefully where *thermally
massive* components are attached.
Assembly may well have moved along from the *solder bath* technique
where a wave of molten solder washes over the back of the assembled
board, but, localised *chilling* can lead to poor quality connections.

I once bought an ex rental colour tv that required percussive
maintenance to get the colour back

I discovered instead of through hole plating, it had some form of pop
rivet connecting tracks on either side of the board. I soldered every
single one. Both sides...took me a whole afternoon.

The TV was rock solid for years until it got destroyed by a direct
lightning strike on the house phone line.

It wasn't worth repairing...

--
I would rather have questions that cannot be answered...
...than to have answers that cannot be questioned

Richard Feynman

Tim+

2023-01-25 18:25:27 UTC

Post by Stephen Howarth
Hi, I don't know if this thread is still open but I have a problem with
my White Knight Eco43A gas tumble dryer.
When it is switched on from cold, the gas comes on and ignites and runs
for about 4 minutes in a clockwise direction. The gas then turns off, the
drum reverses (anticlockwise) and then starts up again in the clockwise
direction. The gas ignites but now only runs for about 8 seconds. It will
continue to do this for the rest of the cycle until it finishes.
I have cleaned out all the air ducts, both inlet and exhaust thoroughly,
the flexible exhaust pipe and outlet vent, inside is spotless.
I initially suspected the gas failure electrode but it will allow it to
fire up for 4 minutes initially. Could this be failing once it got hot?
I have changed the inlet thermostats thinking that these could be the
problem for a second hand pair from e bay. After fitting these, it did
two cycles of 4 minute gas runs then went back to cutting off after 8
seconds on subsequent cycles.
Has anyone else encountered and solved this problem?
It's an old (but normally good) machine and I don't want to change it if
there's a relatively cost effective fix.
My thoughts following the inlet stats were:-
1. Flame failure electrode
2. Exhaust Stats
3. Gas control unit
I was also struggling with sourcing parts, hence getting second hand
stats from e bay. Is there anyone who keeps these bits or would have
suitable replacements?
Thanks in advance.

8 seconds sounds like too quick for it to be overheating and tripping a
stat, more like a failure to detect a flame on subsequent ignitions or a
fault with the gas control unit that is causing a failure to detect a flame
once the unit has warmed up perhaps.

As it happens I have a control unit sitting in my garage but my machine
predated your (1990) and didn’t have a reversing function so I suspect it
wouldn’t be a straight swap. It was erratic ignition that finally forced
me to retire my White Knight so I could be that my control unit is faulty
too.

Tim

--
Please don't feed the trolls

Tim+

2023-01-25 18:49:35 UTC

Post by Stephen Howarth
Hi, I don't know if this thread is still open but I have a problem with
my White Knight Eco43A gas tumble dryer.
When it is switched on from cold, the gas comes on and ignites and runs
for about 4 minutes in a clockwise direction. The gas then turns off, the
drum reverses (anticlockwise) and then starts up again in the clockwise
direction. The gas ignites but now only runs for about 8 seconds. It will
continue to do this for the rest of the cycle until it finishes.
I have cleaned out all the air ducts, both inlet and exhaust thoroughly,
the flexible exhaust pipe and outlet vent, inside is spotless.
I initially suspected the gas failure electrode but it will allow it to
fire up for 4 minutes initially. Could this be failing once it got hot?
I have changed the inlet thermostats thinking that these could be the
problem for a second hand pair from e bay. After fitting these, it did
two cycles of 4 minute gas runs then went back to cutting off after 8
seconds on subsequent cycles.
Has anyone else encountered and solved this problem?
It's an old (but normally good) machine and I don't want to change it if
there's a relatively cost effective fix.
My thoughts following the inlet stats were:-
1. Flame failure electrode
2. Exhaust Stats
3. Gas control unit
I was also struggling with sourcing parts, hence getting second hand
stats from e bay. Is there anyone who keeps these bits or would have
suitable replacements?
Thanks in advance.

8 seconds sounds like too quick for it to be overheating and tripping a
stat, more like a failure to detect a flame on subsequent ignitions or a
fault with the gas control unit that is causing a failure to detect a flame
once the unit has warmed up perhaps.
As it happens I have a control unit sitting in my garage but my machine
predated your (1990) and didn’t have a reversing function so I suspect it
wouldn’t be a straight swap. It was erratic ignition that finally forced
me to retire my White Knight so I could be that my control unit is faulty
too.

I should have added I have the old exhaust and inlet stats too if you’re
sure that’s the problem

Tim

--
Please don't feed the trolls

Stephen Howarth

2023-01-25 22:07:26 UTC

Post by Stephen Howarth
Hi, I don't know if this thread is still open but I have a problem with
my White Knight Eco43A gas tumble dryer.
When it is switched on from cold, the gas comes on and ignites and runs
for about 4 minutes in a clockwise direction. The gas then turns off, the
drum reverses (anticlockwise) and then starts up again in the clockwise
direction. The gas ignites but now only runs for about 8 seconds. It will
continue to do this for the rest of the cycle until it finishes.
I have cleaned out all the air ducts, both inlet and exhaust thoroughly,
the flexible exhaust pipe and outlet vent, inside is spotless.
I initially suspected the gas failure electrode but it will allow it to
fire up for 4 minutes initially. Could this be failing once it got hot?
I have changed the inlet thermostats thinking that these could be the
problem for a second hand pair from e bay. After fitting these, it did
two cycles of 4 minute gas runs then went back to cutting off after 8
seconds on subsequent cycles.
Has anyone else encountered and solved this problem?
It's an old (but normally good) machine and I don't want to change it if
there's a relatively cost effective fix.
My thoughts following the inlet stats were:-
1. Flame failure electrode
2. Exhaust Stats
3. Gas control unit
I was also struggling with sourcing parts, hence getting second hand
stats from e bay. Is there anyone who keeps these bits or would have
suitable replacements?
Thanks in advance.

8 seconds sounds like too quick for it to be overheating and tripping a
stat, more like a failure to detect a flame on subsequent ignitions or a
fault with the gas control unit that is causing a failure to detect a flame
once the unit has warmed up perhaps.
As it happens I have a control unit sitting in my garage but my machine
predated your (1990) and didn’t have a reversing function so I suspect it
wouldn’t be a straight swap. It was erratic ignition that finally forced
me to retire my White Knight so I could be that my control unit is faulty
too.

I should have added I have the old exhaust and inlet stats too if you’re
sure that’s the problem
Tim
--
Please don't feed the trolls

Thanks for your replies gents.
Tim, I'm not sure that changing the exhaust stats would fix it or not? (Changing the inlets didn't)
If I've read it correctly, the manual seems to indicate that the exhaust stats control the high/low heat setting?
You wouldn't by any chance have the flame failure electrode? Or know where I could find one please?
Many Thanks

Tim+

2023-01-25 22:39:22 UTC

Post by Stephen Howarth
Thanks for your replies gents.
Tim, I'm not sure that changing the exhaust stats would fix it or not?
(Changing the inlets didn't)
If I've read it correctly, the manual seems to indicate that the exhaust
stats control the high/low heat setting?

Agreed, I don’t think that they’re your problem.

Post by Stephen Howarth
You wouldn't by any chance have the flame failure electrode? Or know
where I could find one please?
Many Thanks

I have the one in my burner, but it looks a bit like a bit of sucked
toffee. It’s eroded over the years and identical replacements are
unobtainable. Maybe it’s possible that a similar electrode from a gas
boiler could be made to work but I was never brave enough to try. Have you
tried cleaning up your electrode with emery cloth or similar?

The whole ignition sequence seems to be very “fail-safe” so I don’t think
using a different manufacturer’s electrode would be dangerous (assuming you
could fit it). Maybe have a look on eBay for “flame failure electrodes”
and maybe go for the closet visual match?

I would perhaps have tried in my machine if it hadn’t been for the fact
that the paddles in the drum were also disintegrating.

Tim

--
Please don't feed the trolls

Fredxx

2023-01-27 00:56:37 UTC

Post by Stephen Howarth
Hi, I don't know if this thread is still open but I have a problem with
my White Knight Eco43A gas tumble dryer.
When it is switched on from cold, the gas comes on and ignites and runs
for about 4 minutes in a clockwise direction. The gas then turns off,
the drum reverses (anticlockwise) and then starts up again in the
clockwise direction. The gas ignites but now only runs for about 8
seconds. It will continue to do this for the rest of the cycle until it
finishes. I have cleaned out all the air ducts, both inlet and exhaust
thoroughly, the flexible exhaust pipe and outlet vent, inside is
spotless. I initially suspected the gas failure electrode but it will
allow it to fire up for 4 minutes initially. Could this be failing once
it got hot?
I have changed the inlet thermostats thinking that these could be the
problem for a second hand pair from e bay. After fitting these, it did
two cycles of 4 minute gas runs then went back to cutting off after 8
seconds on subsequent cycles. Has anyone else encountered and solved
this problem? It's an old (but normally good) machine and I don't want
to change it if there's a relatively cost effective fix. My thoughts
following the inlet stats were:-
1. Flame failure electrode
2. Exhaust Stats
3. Gas control unit I was also struggling with sourcing parts, hence
getting second hand stats from e bay. Is there anyone who keeps these
bits or would have suitable replacements? Thanks in advance.

A flame sensor relies on conduction in the flame. The burner is grounded
and a small current passes through the flame sensor electrode when the
flame is lit.
https://en.wikipedia.org/wiki/Flame_rectification

In such a gas safety environment, I would expect the gas valve would
only be allowed to open if there is nor flame sensed, ie no conduction.

The fact it lights suggests that that part is at least working ok. When
lit I don't know the criterion used by the manufacturer that the flame
is lit. Is it expecting a rectified current between some limits?

A boiler engineer suggested that cleaning the electrode can have a
dramatic effect. Stainless steel tarnishes over time and affects the
measurement. I would give the electrode, not the insulator, a good rub
with emery or similar abrasive material to clean the electrode, at least
the part in the flame.

Stephen Howarth

2023-01-27 09:06:08 UTC

Post by Stephen Howarth
Hi, I don't know if this thread is still open but I have a problem with
my White Knight Eco43A gas tumble dryer.
When it is switched on from cold, the gas comes on and ignites and runs
for about 4 minutes in a clockwise direction. The gas then turns off,
the drum reverses (anticlockwise) and then starts up again in the
clockwise direction. The gas ignites but now only runs for about 8
seconds. It will continue to do this for the rest of the cycle until it
finishes. I have cleaned out all the air ducts, both inlet and exhaust
thoroughly, the flexible exhaust pipe and outlet vent, inside is
spotless. I initially suspected the gas failure electrode but it will
allow it to fire up for 4 minutes initially. Could this be failing once
it got hot?
I have changed the inlet thermostats thinking that these could be the
problem for a second hand pair from e bay. After fitting these, it did
two cycles of 4 minute gas runs then went back to cutting off after 8
seconds on subsequent cycles. Has anyone else encountered and solved
this problem? It's an old (but normally good) machine and I don't want
to change it if there's a relatively cost effective fix. My thoughts
following the inlet stats were:-
1. Flame failure electrode
2. Exhaust Stats
3. Gas control unit I was also struggling with sourcing parts, hence
getting second hand stats from e bay. Is there anyone who keeps these
bits or would have suitable replacements? Thanks in advance.

A flame sensor relies on conduction in the flame. The burner is grounded
and a small current passes through the flame sensor electrode when the
flame is lit.
https://en.wikipedia.org/wiki/Flame_rectification
In such a gas safety environment, I would expect the gas valve would
only be allowed to open if there is nor flame sensed, ie no conduction.
The fact it lights suggests that that part is at least working ok. When
lit I don't know the criterion used by the manufacturer that the flame
is lit. Is it expecting a rectified current between some limits?
A boiler engineer suggested that cleaning the electrode can have a
dramatic effect. Stainless steel tarnishes over time and affects the
measurement. I would give the electrode, not the insulator, a good rub
with emery or similar abrasive material to clean the electrode, at least
the part in the flame.

Thank you gents for your suggestions.
I will take the electrode out of the machine today, check the wire and clean around where it bolts to the body, I suspect it probably does earth through there Alan.
I did clean the electrode yesterday Fred but I did it in place.
Tim, I'll have a look in the control unit too
Many thanks.for your help.

Tim+

2023-01-27 10:15:16 UTC

Post by Stephen Howarth
Hi, I don't know if this thread is still open but I have a problem with
my White Knight Eco43A gas tumble dryer.
When it is switched on from cold, the gas comes on and ignites and runs
for about 4 minutes in a clockwise direction. The gas then turns off,
the drum reverses (anticlockwise) and then starts up again in the
clockwise direction. The gas ignites but now only runs for about 8
seconds. It will continue to do this for the rest of the cycle until it
finishes. I have cleaned out all the air ducts, both inlet and exhaust
thoroughly, the flexible exhaust pipe and outlet vent, inside is
spotless. I initially suspected the gas failure electrode but it will
allow it to fire up for 4 minutes initially. Could this be failing once
it got hot?
I have changed the inlet thermostats thinking that these could be the
problem for a second hand pair from e bay. After fitting these, it did
two cycles of 4 minute gas runs then went back to cutting off after 8
seconds on subsequent cycles. Has anyone else encountered and solved
this problem? It's an old (but normally good) machine and I don't want
to change it if there's a relatively cost effective fix. My thoughts
following the inlet stats were:-
1. Flame failure electrode
2. Exhaust Stats
3. Gas control unit I was also struggling with sourcing parts, hence
getting second hand stats from e bay. Is there anyone who keeps these
bits or would have suitable replacements? Thanks in advance.

Um, if there’s a flame then the valve is already open. ;-) The flame
detection comes into play after the valve opens. If no flame detected
within a certain number of seconds, the valve closes.

Post by Fredxx
The fact it lights suggests that that part is at least working ok.

That just tells you that the igniter is working. It doesn’t tell you
anything about the flame detector.

Tim

--
Please don't feed the trolls

Fredxx

2023-01-27 13:29:14 UTC

Post by Stephen Howarth
Hi, I don't know if this thread is still open but I have a problem with
my White Knight Eco43A gas tumble dryer.
When it is switched on from cold, the gas comes on and ignites and runs
for about 4 minutes in a clockwise direction. The gas then turns off,
the drum reverses (anticlockwise) and then starts up again in the
clockwise direction. The gas ignites but now only runs for about 8
seconds. It will continue to do this for the rest of the cycle until it
finishes. I have cleaned out all the air ducts, both inlet and exhaust
thoroughly, the flexible exhaust pipe and outlet vent, inside is
spotless. I initially suspected the gas failure electrode but it will
allow it to fire up for 4 minutes initially. Could this be failing once
it got hot?
I have changed the inlet thermostats thinking that these could be the
problem for a second hand pair from e bay. After fitting these, it did
two cycles of 4 minute gas runs then went back to cutting off after 8
seconds on subsequent cycles. Has anyone else encountered and solved
this problem? It's an old (but normally good) machine and I don't want
to change it if there's a relatively cost effective fix. My thoughts
following the inlet stats were:-
1. Flame failure electrode
2. Exhaust Stats
3. Gas control unit I was also struggling with sourcing parts, hence
getting second hand stats from e bay. Is there anyone who keeps these
bits or would have suitable replacements? Thanks in advance.

Um, if there’s a flame then the valve is already open. ;-) The flame
detection comes into play after the valve opens. If no flame detected
within a certain number of seconds, the valve closes.

I would have thought the gas vale would open when no flame is sensed, as
a precaution to a faulty sensor failing in a positive sense.

Post by Fredxx
The fact it lights suggests that that part is at least working ok.

That just tells you that the igniter is working. It doesn’t tell you
anything about the flame detector.

Yer-but, it also tells us the system thinks the flame sensor is actually
working and not failing in a false positive with no flame.

I'm pretty sure my gas valve won't open and indicate a faulty electrode
if it senses a flame when one shouldn't be there.

While I would be tempted to put a DVM (Volts) on the sensor wire, I'm
not sure if it would be high enough resistance so as to not interfere
with the rest of the circuit.

Fredxx

2023-01-27 13:46:03 UTC

Post by Stephen Howarth
Hi, I don't know if this thread is still open but I have a problem with
my White Knight Eco43A gas tumble dryer.
When it is switched on from cold, the gas comes on and ignites and runs
for about 4 minutes in a clockwise direction. The gas then turns off,
the drum reverses (anticlockwise) and then starts up again in the
clockwise direction. The gas ignites but now only runs for about 8
seconds. It will continue to do this for the rest of the cycle until it
finishes. I have cleaned out all the air ducts, both inlet and exhaust
thoroughly, the flexible exhaust pipe and outlet vent, inside is
spotless. I initially suspected the gas failure electrode but it will
allow it to fire up for 4 minutes initially. Could this be failing once
it got hot?
I have changed the inlet thermostats thinking that these could be the
problem for a second hand pair from e bay. After fitting these, it did
two cycles of 4 minute gas runs then went back to cutting off after 8
seconds on subsequent cycles. Has anyone else encountered and solved
this problem? It's an old (but normally good) machine and I don't want
to change it if there's a relatively cost effective fix. My thoughts
following the inlet stats were:-
1. Flame failure electrode
2. Exhaust Stats
3. Gas control unit I was also struggling with sourcing parts, hence
getting second hand stats from e bay. Is there anyone who keeps these
bits or would have suitable replacements? Thanks in advance.

Um, if there’s a flame then the valve is already open. ;-) The flame
detection comes into play after the valve opens. If no flame detected
within a certain number of seconds, the valve closes.

I would have thought the gas valve would open when a flame is sensed, as

^^^^ ^^^^
not

a precaution to a faulty sensor failing in a positive sense.

Post by Fredxx
The fact it lights suggests that that part is at least working ok.

That just tells you that the igniter is working. It doesn’t tell you
anything about the flame detector.

Yer-but, it also tells us the system thinks the flame sensor is actually
working and not failing in a false positive with no flame.
I'm pretty sure my gas valve won't open and indicate a faulty electrode
if it senses a flame when one shouldn't be there.
While I would be tempted to put a DVM (Volts) on the sensor wire, I'm
not sure if it would be high enough resistance so as to not interfere
with the rest of the circuit.

John Rumm

2023-01-27 16:30:23 UTC