I have a Baxi 105e Instant combi. The heating is an underfloor system
run from this boiler.
The pressure on the boiler seems to have dropped to below 1/2 bar.
It has done this twice before, which led me to think it was a leak.
The underfloor heating circuits were tested for leaks during
installation and were fine - No leaks.
The second time this happened i thought it might be the fact the auto
bleed valve on the pump was left open. Is it ok to leave the auto
bleed valve open?
Anyway it's closed and the pressure still dropped!
There is also a squeal type noise when the boiler kicks in (either
from heating demand or hot tap). I think this may be the pump or
diverter valve. Would running the system at low pressure cause damage
to these devices?
There are no signs of leaks from the actual boiler itself, so i don't
think it is the expansion vessel.
The only thing that is a bit suspect is the UFH manifold.
I never checked this and there is (very) slight evidence of a leak
around one of the ports. I can't see how a 1bar pressure drop could
produce such little water?
Anyone have any advice (apart from calling a plumber!)