Baxi Combi Boiler 105HE Losing Pressure

fonzyg50

Hi all

hope you all had a good xmas and new year, i have a problem and need some advice with my combi boiler baxi 105he.

The pressure gauge on boiler was showing 0, so i filled it up to 1.5 using the filling loop, next day the pressure dropped to 0 and again i filled it up.

I went round all radiators to bleed the air out and found out that my bedroom, baby bedroom and downstairs kitchen had air in them.

anyway once i bled the radiators i filled it up again to 1.5 only to drop again next day.

n power engineer came round and cannot find a problem, PRV LOOKED FINE AND NO LEAKS from outlet, PRESSURE VESSEL SEEMS GOOD AS HE DONE A TEST ON THIS ( he whacked up the heating to see if it rise to 3 on the gauge) , So he reckons it must be a leak on the central heating system, i took up floorboards checked all pipes and no leaks anywhere, this is really puzzling me,

hope some of you can help me

thankyou so much

macman

The engineer is correct. Those are the 3 main suspects, and the first two appear to have been eliminated. The problem with small CH circuit leaks is that, with then heating on, the water will often evaporate before it can be detected.

southcoastrgi

there is another one that it could be, re-pressurise the boiler then isolate it by turning off the flow & return connections (although these may start leaking) leave it for 24hrs (not working of course), & see if the pressure drops ? tape a plastic bag over the prv pipe outside & see if you get water in it (a visual inspection sometimes isn't good enough), if no water in the bag, no water inside the boiler & the pressure still drops it could be a knackered heat exchanger

fonzyg50

All fixed, it was the secondary heat exchange unit