Vaillant firing when no call for heat

[Harry Bloomfield]

Some months ago, I had a new Vaillant ECOfit Pure 18Kw installed as a
replacement boiler, in a special cupboard for the purpose, in the
kitchen. Since when - during the day, with the timeclock set to allow
heating, but with no demand for heating, I would occasionally catch the
boiler firing up briefly or maybe doing a purge. It is set to bring the
HW tank up to temperature once per day, or on a push a button demand.

I emailed Vaillant to ask if it was maybe designed to do this - no
reply, so last week I rang them. They expressed no opinion whether it
should or shouldn't, but suggested catching the boiler when I heard it
running and pressing certain buttons to produce its reason for firing
code.

Since then and trying to do that, I have had the cupboard door open to
better hear it fire, but not once have I heard it fire :/

I can force it to fire up briefly at anytime, by pressing the 'on'
button on the boiler. The resulting brief run, seems similar to the
ghost firing I am complaining about.

[Brian Gaff]

So are you suggesting that its got a sensor that does not like to be in a
sealed enclosure?
are there not any ventilation holes in it?
Brian
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Post by Harry Bloomfield
Some months ago, I had a new Vaillant ECOfit Pure 18Kw installed as a
replacement boiler, in a special cupboard for the purpose, in the kitchen.
Since when - during the day, with the timeclock set to allow heating, but
with no demand for heating, I would occasionally catch the boiler firing
up briefly or maybe doing a purge. It is set to bring the HW tank up to
temperature once per day, or on a push a button demand.
I emailed Vaillant to ask if it was maybe designed to do this - no reply,
so last week I rang them. They expressed no opinion whether it should or
shouldn't, but suggested catching the boiler when I heard it running and
pressing certain buttons to produce its reason for firing code.
Since then and trying to do that, I have had the cupboard door open to
better hear it fire, but not once have I heard it fire :/
I can force it to fire up briefly at anytime, by pressing the 'on' button
on the boiler. The resulting brief run, seems similar to the ghost firing
I am complaining about.

[Harry Bloomfield]

Post by Brian Gaff
So are you suggesting that its got a sensor that does not like to be in a
sealed enclosure?
are there not any ventilation holes in it?
Brian

No, I am not suggesting that - the cupboard is purely cosmetic, open
top and bottom, plenty of space at the sides and front. I built it to
accept a much larger boiler, long ago.

My original thoughts were, that the boiler would run a purge every so
often just to exercise itself - pumps etc., if it hadn't been called
for a while. That was the sort of brief cycling I was witnessing.

[John Rumm]

Post by Brian Gaff
So are you suggesting that its got a sensor that does not like to be
in a sealed enclosure?
 are there not any ventilation holes in it?
 Brian

No, I am not suggesting that - the cupboard is purely cosmetic, open top
and bottom, plenty of space at the sides and front. I built it to accept
a much larger boiler, long ago.
My original thoughts were, that the boiler would run a purge every so
often just to exercise itself - pumps etc., if it hadn't been called for
a while. That was the sort of brief cycling I was witnessing.

Many of the Vaillant boilers seem to have similar facilities - basically
to exercise fans, pumps, valves etc to make sure they don't seize during
periods of low use.
--
Cheers,

John.

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[Harry Bloomfield]

Many of the Vaillant boilers seem to have similar facilities - basically to
exercise fans, pumps, valves etc to make sure they don't seize during periods
of low use.

The Vaillant help desk tec didn't seem to suggest, or realise it had
such a facility. It seemed to be once per day, but at no particular
timing. HW is triggered once per day at 16:20.

[John Rumm]

Post by Harry Bloomfield

Post by John Rumm
Many of the Vaillant boilers seem to have similar facilities -
basically to exercise fans, pumps, valves etc to make sure they don't
seize during periods of low use.

The Vaillant help desk tec didn't seem to suggest, or realise it had
such a facility. It seemed to be once per day, but at no particular
timing. HW is triggered once per day at 16:20.

I have a feeling, its mentioned somewhere in the documentation for mine...
--
Cheers,

John.

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

[Harry Bloomfield]

Post by John Rumm
I have a feeling, its mentioned somewhere in the documentation for mine...

If it is in my documentation, I have been unable to spot it.

To be fair, I would be surprised if it didn't exercise things
regularly.

[Jethro_uk]

My Vaillant has a feature designed to minimise the delay between calling
for hot water, and delivering it. It tries to keep the internal
temperature around 60-70C. So will fire every so often.

It can be enabled/disabled from the front panel where the DHW temperature
is set.

[Harry Bloomfield]

Post by Jethro_uk
My Vaillant has a feature designed to minimise the delay between calling
for hot water, and delivering it. It tries to keep the internal
temperature around 60-70C. So will fire every so often.
It can be enabled/disabled from the front panel where the DHW temperature
is set.

I have an open vented HW and heating circuits by choice. So this is
just being used as a simple boiler system.

[John Rumm]

Post by Jethro_uk
My Vaillant has a feature designed to minimise the delay between calling
for hot water, and delivering it. It tries to keep the internal
temperature around 60-70C. So will fire every so often.
It can be enabled/disabled from the front panel where the DHW temperature
is set.

That's usually on the 800 series combi boilers.
--
Cheers,

John.

/=================================================================\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
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\=================================================================/

[dennis@home]

Post by Harry Bloomfield
Some months ago, I had a new Vaillant ECOfit Pure 18Kw installed as a
replacement boiler, in a special cupboard for the purpose, in the
kitchen. Since when - during the day, with the timeclock set to allow
heating, but with no demand for heating, I would occasionally catch the
boiler firing up briefly or maybe doing a purge. It is set to bring the
HW tank up to temperature once per day, or on a push a button demand.
I emailed Vaillant to ask if it was maybe designed to do this - no
reply, so last week I rang them. They expressed no opinion whether it
should or shouldn't, but suggested catching the boiler when I heard it
running and pressing certain buttons to produce its reason for firing code.
Since then and trying to do that, I have had the cupboard door open to
better hear it fire, but not once have I heard it fire :/
I can force it to fire up briefly at anytime, by pressing the 'on'
button on the boiler. The resulting brief run, seems similar to the
ghost firing I am complaining about.

The person that fitted my Valliant forgot to remove the 24V link when
using mains ON.
This causes the boiler to cycle.
I had quite a hard time explaining the mistake to the "engineer" that
came to investigate the problem after I spotted the link still being in
place.
It would have been easier for me to have opened it up and looked myself
in the first place.

[Graham.]

Post by Harry Bloomfield
Some months ago, I had a new Vaillant ECOfit Pure 18Kw installed as a
replacement boiler, in a special cupboard for the purpose, in the
kitchen. Since when - during the day, with the timeclock set to allow
heating, but with no demand for heating, I would occasionally catch the
boiler firing up briefly or maybe doing a purge. It is set to bring the
HW tank up to temperature once per day, or on a push a button demand.
I emailed Vaillant to ask if it was maybe designed to do this - no
reply, so last week I rang them. They expressed no opinion whether it
should or shouldn't, but suggested catching the boiler when I heard it
running and pressing certain buttons to produce its reason for firing
code.
Since then and trying to do that, I have had the cupboard door open to
better hear it fire, but not once have I heard it fire :/
I can force it to fire up briefly at anytime, by pressing the 'on'
button on the boiler. The resulting brief run, seems similar to the
ghost firing I am complaining about.

Does the system have a wireless thermostat?

[Harry Bloomfield]

Post by Graham.
Does the system have a wireless thermostat?

A wireless room stat., yes..

[Graham.]

Post by Harry Bloomfield

Post by Graham.
Does the system have a wireless thermostat?

A wireless room stat., yes..

Consider the possibility that the receiver is picking up an ON command
occasionly from another device nearby.

My radiators came on mysteriously in the night on two occasions during
the recent heat wave The pairing was done via 8 bit DIP switches in
the stat and receiver, since I changed the code it seems to be OK.
The original setting was not the manufacturer default (all OFF) I
thought that would be asking for trouble.