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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Plumbing Questions >> Pressure Gauge on Baxi Condensing Boiler https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1127127939 Message started by CWall on Sep 19^th, 2005, 12:05pm

Title: Pressure Gauge on Baxi Condensing Boiler
Post by CWall on Sep 19^th, 2005, 12:05pm

Hi, I was wondering whether I could get some advice or tips regarding a small problem with our 5 month old Baxi Condensing Combi Boiler. We have noticed that recently the pressure gauge is sitting idol at 2.3 and when the hot water is turned on it shoots up to 2.5 or even 3! It says on the instructions that normal operating pressure is between 1 and 2.5 and anything over this indicates a fault. I've telephoned the installers who advised that this was ok and nothing to worry about, but I'm not too sure can anyone help ???

Title: Re: Pressure Gauge on Baxi Condensing Boiler
Post by HandyJon on Sep 19^th, 2005, 7:34pm

When water heats up it expands, so the pressure will go up a bit when the heating is on. Nothing to worry about. The boiler will have a pressure relief value if the pressure goes too high so it won't explode.

Title: Re: Pressure Gauge on Baxi Condensing Boiler
Post by thescruff on Sep 19^th, 2005, 10:53pm

Well it's certainly not normall to go that high and suggests a problem.

At about 3bar the boiler will discharge water, which could mean topping up when it cools.

2.3 bar cold is too high and should be lowered to 1-1.5 bar max, but how did it get that high in the first place, is the filler loop disconnected.

Another problem with larger system, and it will depend on the boiler model, but the expansion vessel is sized for about 130 litres anything over that will require an additional expansion vessel.

in other words more info on the system please.

Title: Re: Pressure Gauge on Baxi Condensing Boiler
Post by CWall on Sep 20^th, 2005, 6:06pm

I don't know why it's suddenly gone this high, we only noticed it a few days ago.

Should the filler loop be connected or disconnected? How would I find out? The boiler is servicing 9 radiators and the model number is: Baxi Combi 105 HE

How can I lower the pressure?

Sorry to sound ignorant, but I'm not overly familiar with this subject :)

Title: Re: Pressure Gauge on Baxi Condensing Boiler
Post by thescruff on Sep 20^th, 2005, 8:13pm

The filler loop should be disconnected (water regs)

Lower the pressure to 1.5 bar maximum when the boiler and rads are cold, then record the high pressure when the system is hot.

To lower the pressure simple drain some water out the draincock or air vent, it will not be much.

Title: Re: Pressure Gauge on Baxi Condensing Boiler
Post by CWall on Sep 22^nd, 2005, 1:24pm

:D Thanks very much for the advice, I'll try it this afternoon and let you know the results ;D