Post by alan_m Post by Tim+
We have a Baxi Brazilia heater.
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
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.
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
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.
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.
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.
Please don't feed the trolls