Discussion:
Baxi Brazilia puzzle
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Tim+
2021-10-12 16:24:47 UTC
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We have a Baxi Brazilia heater.
https://www.wolseley.co.uk/product/baxi-brazilia-f8s-wall-heater-ng-oak/

Very basic. Wall mounted, room sealed, balanced flue, spark igniter, no
thermocouple, dead reliable.

Well that is until last week. I lit it, it ran for a while (maybe 10-20
minutes) and then went out. It repeated this on the next occasion.

Today, I took the outer cover off and it ran perfectly. The cover doesn’t
in any way affect the air supply to the burner as it’s room sealed but does
turn more of the radiant heat from the heater into convected heat. The
heater is noticeably warmer to be near with the cover off.

Could removing the cover be reducing the heat exchanger temperature enough
to alter its internal airflow and air supply to the burner?

Can’t think of another reason why removing the cover should have made a
difference.

If/when I can track down a new seal for the heat exchanger I might crack it
open to look at the burner but don’t want to disturb the seal before I have
a new one.

Tim
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Harry Bloomfield, Esq.
2021-10-12 17:58:57 UTC
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Post by Tim+
Can’t think of another reason why removing the cover should have made a
difference.
If/when I can track down a new seal for the heat exchanger I might crack it
open to look at the burner but don’t want to disturb the seal before I have
a new one.
Or it could be the thermocouple going a touch low in output, or poorly
aligned.
Tim+
2021-10-12 18:01:38 UTC
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Post by Harry Bloomfield, Esq.
Post by Tim+
Can’t think of another reason why removing the cover should have made a
difference.
If/when I can track down a new seal for the heat exchanger I might crack it
open to look at the burner but don’t want to disturb the seal before I have
a new one.
Or it could be the thermocouple going a touch low in output, or poorly
aligned.
“no thermocouple”
Tim
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alan_m
2021-10-12 18:32:31 UTC
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Post by Harry Bloomfield, Esq.
Post by Tim+
Can’t think of another reason why removing the cover should have made a
difference.
If/when I can track down a new seal for the heat exchanger I might crack it
open to look at the burner but don’t want to disturb the seal before I have
a new one.
Or it could be the thermocouple going a touch low in output, or poorly
aligned.
“no thermocouple”
Tim
The manual at
https://www.wolseley.co.uk/product/baxi-brazilia-f8s-wall-heater-ng-oak/

Page 12 shows a thermocouple
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Owain Lastname
2021-10-12 18:57:28 UTC
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Post by alan_m
Post by Harry Bloomfield, Esq.
“no thermocouple”
The manual at
https://www.wolseley.co.uk/product/baxi-brazilia-f8s-wall-heater-ng-oak/
Page 12 shows a thermocouple
Maybe newer ones have a thermocouple as a flame failure device, and olderones don't?

Owain
Harry Bloomfield, Esq.
2021-10-13 09:56:10 UTC
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Post by Owain Lastname
Maybe newer ones have a thermocouple as a flame failure device, and olderones don't?
As an alternative to a thermocouple to sense the flame, they can use an
electronic system, with a probe in the flame.
Owain Lastname
2021-10-13 10:42:52 UTC
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Post by Harry Bloomfield, Esq.
As an alternative to a thermocouple to sense the flame, they can use an
electronic system, with a probe in the flame.
One of the attractions of that sort of heater is they don't need any electricity, which makes them useful in caravans and site huts etc.

Owain
Fredxx
2021-10-12 19:10:26 UTC
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Post by alan_m
Post by Harry Bloomfield, Esq.
Post by Tim+
Can’t think of another reason why removing the cover should have made a
difference.
If/when I can track down a new seal for the heat exchanger I might crack it
open to look at the burner but don’t want to disturb the seal before I have
a new one.
Or it could be the thermocouple going a touch low in output, or poorly
aligned.
“no thermocouple”
Tim
The manual at
https://www.wolseley.co.uk/product/baxi-brazilia-f8s-wall-heater-ng-oak/
Page 12 shows a thermocouple
The Wolsey site seems broken and for me the manual there is for a
completely different appliance.

However:

https://www.valor.co.uk/sites/default/files/assets//048_Brazilia_Installation_Instructions_Issue_3.pdf

does show a thermocouple on page 12.
Tim+
2021-10-12 19:42:50 UTC
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Post by Fredxx
Post by alan_m
Post by Harry Bloomfield, Esq.
Post by Tim+
Can’t think of another reason why removing the cover should have made a
difference.
If/when I can track down a new seal for the heat exchanger I might crack it
open to look at the burner but don’t want to disturb the seal before I have
a new one.
Or it could be the thermocouple going a touch low in output, or poorly
aligned.
“no thermocouple”
Tim
The manual at
https://www.wolseley.co.uk/product/baxi-brazilia-f8s-wall-heater-ng-oak/
Page 12 shows a thermocouple
The Wolsey site seems broken and for me the manual there is for a
completely different appliance.
https://www.valor.co.uk/sites/default/files/assets//048_Brazilia_Installation_Instructions_Issue_3.pdf
does show a thermocouple on page 12.
Mine is about 30 years old and has no thermocouple. It lights instantly
with no need to hold the knob in. Nor does the gas shut off if the flame
fails.

Tim
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Please don't feed the trolls
Tim+
2021-10-12 19:42:50 UTC
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Post by alan_m
Post by Harry Bloomfield, Esq.
Post by Tim+
Can’t think of another reason why removing the cover should have made a
difference.
If/when I can track down a new seal for the heat exchanger I might crack it
open to look at the burner but don’t want to disturb the seal before I have
a new one.
Or it could be the thermocouple going a touch low in output, or poorly
aligned.
“no thermocouple”
Tim
The manual at
https://www.wolseley.co.uk/product/baxi-brazilia-f8s-wall-heater-ng-oak/
Page 12 shows a thermocouple
Mine predates that. That was just the first similar model I found on line.
My mistake. Mine *definitely* has no thermocouple.

Tim
--
Please don't feed the trolls
alan_m
2021-10-13 11:45:04 UTC
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Post by Tim+
We have a Baxi Brazilia heater.
https://www.wolseley.co.uk/product/baxi-brazilia-f8s-wall-heater-ng-oak/
Very basic. Wall mounted, room sealed, balanced flue, spark igniter, no
thermocouple, dead reliable.
Well that is until last week. I lit it, it ran for a while (maybe 10-20
minutes) and then went out. It repeated this on the next occasion.
Today, I took the outer cover off and it ran perfectly. The cover doesn’t
in any way affect the air supply to the burner as it’s room sealed but does
turn more of the radiant heat from the heater into convected heat. The
heater is noticeably warmer to be near with the cover off.
Could removing the cover be reducing the heat exchanger temperature enough
to alter its internal airflow and air supply to the burner?
Can’t think of another reason why removing the cover should have made a
difference.
If/when I can track down a new seal for the heat exchanger I might crack it
open to look at the burner but don’t want to disturb the seal before I have
a new one.
Tim
Is there a metal gauze filter associated with the burner that has been
clogged with dust and is restricting air flow? Again, the wrong
instruction manual shows a burner gauze which will be an easily blocked
fine metal mesh.

Pages 12 and 14 of
https://www.valor.co.uk/sites/default/files/assets//048_Brazilia_Installation_Instructions_Issue_3.pdf
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Tim+
2021-10-13 16:05:29 UTC
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Post by alan_m
Post by Tim+
We have a Baxi Brazilia heater.
https://www.wolseley.co.uk/product/baxi-brazilia-f8s-wall-heater-ng-oak/
Very basic. Wall mounted, room sealed, balanced flue, spark igniter, no
thermocouple, dead reliable.
Well that is until last week. I lit it, it ran for a while (maybe 10-20
minutes) and then went out. It repeated this on the next occasion.
Today, I took the outer cover off and it ran perfectly. The cover doesn’t
in any way affect the air supply to the burner as it’s room sealed but does
turn more of the radiant heat from the heater into convected heat. The
heater is noticeably warmer to be near with the cover off.
Could removing the cover be reducing the heat exchanger temperature enough
to alter its internal airflow and air supply to the burner?
Can’t think of another reason why removing the cover should have made a
difference.
If/when I can track down a new seal for the heat exchanger I might crack it
open to look at the burner but don’t want to disturb the seal before I have
a new one.
Tim
Is there a metal gauze filter associated with the burner that has been
clogged with dust and is restricting air flow? Again, the wrong
instruction manual shows a burner gauze which will be an easily blocked
fine metal mesh.
Pages 12 and 14 of
https://www.valor.co.uk/sites/default/files/assets//048_Brazilia_Installation_Instructions_Issue_3.pdf
It’s actually a pretty coarse mesh and it wasn’t blocked. If there was any
blockage then I would expect yellow tips to the flames or soot formation
(of which there was none).

For the doubting Thomas’s here, https://photos.app.goo.gl/rtuwZehrEAoMuUe27

There is no thermocouple!

The burner was clean and whilst there were a few dead insects in the bottom
of the fresh air inlet, there was nothing significant.

https://photos.app.goo.gl/c4BZHH4oDWKYTuf37

The only thing of possible significance that I fished out of the air inlet
from the outside was a ball of what looks like old cobweb.

https://photos.app.goo.gl/BdZZiA8odVsTeJSX6

Whether this would have restricted airflow enough to starve the burner of
enough oxygen to extinguish the flame I don’t know. If that was the
mechanism of failure though, again I would have expected soot formation in
the heat exchanger.

The mystery remains. I’ve put it together again and it seems to be
behaving but until I leave it running for some time I can’t be sure.

Tim
--
Please don't feed the trolls
Harry Bloomfield, Esq.
2021-10-13 18:45:03 UTC
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Post by Tim+
It’s actually a pretty coarse mesh and it wasn’t blocked. If there was any
blockage then I would expect yellow tips to the flames or soot formation
(of which there was none).
For the doubting Thomas’s here, https://photos.app.goo.gl/rtuwZehrEAoMuUe27
Another possibility, is that the flame is simply lifting off the
burner, due to too much air flow draft. Once it is lifted high enough,
it can go out.
Tim+
2021-10-13 18:56:20 UTC
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Post by Harry Bloomfield, Esq.
Post by Tim+
It’s actually a pretty coarse mesh and it wasn’t blocked. If there was any
blockage then I would expect yellow tips to the flames or soot formation
(of which there was none).
For the doubting Thomas’s here, https://photos.app.goo.gl/rtuwZehrEAoMuUe27
Another possibility, is that the flame is simply lifting off the
burner, due to too much air flow draft. Once it is lifted high enough,
it can go out.
It’s never gone out before. Hard to see why the airflow should be higher
than normal when it’s a passive balanced flue setup.

Tim
--
Please don't feed the trolls
Fredxx
2021-10-13 19:26:04 UTC
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Permalink
Post by Tim+
Post by Harry Bloomfield, Esq.
Post by Tim+
It’s actually a pretty coarse mesh and it wasn’t blocked. If there was any
blockage then I would expect yellow tips to the flames or soot formation
(of which there was none).
For the doubting Thomas’s here, https://photos.app.goo.gl/rtuwZehrEAoMuUe27
Another possibility, is that the flame is simply lifting off the
burner, due to too much air flow draft. Once it is lifted high enough,
it can go out.
It’s never gone out before. Hard to see why the airflow should be higher
than normal when it’s a passive balanced flue setup.
Wind, external drafts. Has anything changed outside by the flue?
Tim+
2021-10-13 19:51:40 UTC
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Post by Fredxx
Post by Tim+
Post by Harry Bloomfield, Esq.
Post by Tim+
It’s actually a pretty coarse mesh and it wasn’t blocked. If there was any
blockage then I would expect yellow tips to the flames or soot formation
(of which there was none).
For the doubting Thomas’s here, https://photos.app.goo.gl/rtuwZehrEAoMuUe27
Another possibility, is that the flame is simply lifting off the
burner, due to too much air flow draft. Once it is lifted high enough,
it can go out.
It’s never gone out before. Hard to see why the airflow should be higher
than normal when it’s a passive balanced flue setup.
Wind, external drafts. Has anything changed outside by the flue?
Nope, no changes to the flue. Of course wind is a variable and it’s just
possible gusty wind was responsible. Just odd that it’s never happened
before. Must be global warming. ;-)

Tim
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Please don't feed the trolls
jkn
2021-10-13 16:25:14 UTC
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Post by alan_m
Post by Tim+
We have a Baxi Brazilia heater.
https://www.wolseley.co.uk/product/baxi-brazilia-f8s-wall-heater-ng-oak/
Very basic. Wall mounted, room sealed, balanced flue, spark igniter, no
thermocouple, dead reliable.
Well that is until last week. I lit it, it ran for a while (maybe 10-20
minutes) and then went out. It repeated this on the next occasion.
Today, I took the outer cover off and it ran perfectly. The cover doesn’t
in any way affect the air supply to the burner as it’s room sealed but does
turn more of the radiant heat from the heater into convected heat. The
heater is noticeably warmer to be near with the cover off.
Could removing the cover be reducing the heat exchanger temperature enough
to alter its internal airflow and air supply to the burner?
Can’t think of another reason why removing the cover should have made a
difference.
If/when I can track down a new seal for the heat exchanger I might crack it
open to look at the burner but don’t want to disturb the seal before I have
a new one.
Tim
Is there a metal gauze filter associated with the burner that has been
clogged with dust and is restricting air flow? Again, the wrong
instruction manual shows a burner gauze which will be an easily blocked
fine metal mesh.
Pages 12 and 14 of
https://www.valor.co.uk/sites/default/files/assets//048_Brazilia_Installation_Instructions_Issue_3.pdf
--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk
aka 'lint arrester'. The name game me visions of being something
complicated - when I finally realised what it actually was, and how
crude a 'device', I had to laugh...
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