I have a Baxi Combi boiler about 18months old and has statred loosing pressure. When the heating is on the pressure is fine, but whn no heating on and the water on pre heat pressure bar is at 0, So I keep having to use the vlaves to increase the pressure about every 2 days? Does anyone know what could be the problem? does it sound serious?

Cheers in advance

Try this page..........

http://www.sheffieldforum.co.uk/showthread.php?t=127757&page=20

I have a Baxi Combi boiler about 18months old and has statred loosing pressure. When the heating is on the pressure is fine, but whn no heating on and the water on pre heat pressure bar is at 0, So I keep having to use the vlaves to increase the pressure about every 2 days? Does anyone know what could be the problem? does it sound serious?

Cheers in advance

The waters going (leaking) somewhere. Firstly, what are you increasing the pressure to? Should be set at 1.5bar when cold. If you fill it too high when the heating comes on the boiler will 'blow' it off through its pressure release valve ( a safety device).

Or the actual PRV is leaking due to a faulty seal. There will be a 15mm copper pipe exiting through the wall behind the boiler. Check to see if that is leaking water.

Or you have got a leak somewhere in the system, either in the boiler or the pipes/radiators. To check if its in the boiler isolate the flow and return pipes. Fill the boiler to 1.5 bar first. Both will have isolation valves, usually close them with a flat bladed screwdriver. Need to leave the boiler like this overnight. In the morning if the pressure has dropped - leak is in the boiler. If OK open the valves and if the pressure drops then leak is in the pipework/rads.

[QUOTE=Complete-Heat;2930034]The waters going (leaking) somewhere. Firstly, what are you increasing the pressure to? Should be set at 1.5bar when cold. If you fill it too high when the heating comes on the boiler will 'blow' it off through its pressure release valve ( a safety device).





sorry to hijack this but have been having a similar prob. and I have been topping boiler up to 2 bar and it drops to 0 and shuts off saying showing error F22 in digital disply. I was presuming I had a leek. we have checked but cant see any suspect damp patches...

boiler is valiant and only put in just over a year ago...

[QUOTE=Complete-Heat;2930034]The waters going (leaking) somewhere. Firstly, what are you increasing the pressure to? Should be set at 1.5bar when cold. If you fill it too high when the heating comes on the boiler will 'blow' it off through its pressure release valve ( a safety device).





sorry to hijack this but have been having a similar prob. and I have been topping boiler up to 2 bar and it drops to 0 and shuts off saying showing error F22 in digital disply. I was presuming I had a leek. we have checked but cant see any suspect damp patches...

boiler is valiant and only put in just over a year ago...


Chances are then (unfortunately), the leak is under the ground floor.

Loads of good advise (as usual).
MickyET from here loves Baxi's!!! I'm sure he could help.

AAA Ultimate Plumbing & Heating
01142692464 or 07990821857
www.aaaultimateplumbing.co.uk

Pressure relief valve faulty/expansion vessel needs re-chargeing

[QUOTE=Complete-Heat;2930034]The waters going (leaking) somewhere. Firstly, what are you increasing the pressure to? Should be set at 1.5bar when cold. If you fill it too high when the heating comes on the boiler will 'blow' it off through its pressure release valve ( a safety device).





sorry to hijack this but have been having a similar prob. and I have been topping boiler up to 2 bar and it drops to 0 and shuts off saying showing error F22 in digital disply. I was presuming I had a leek. we have checked but cant see any suspect damp patches...

boiler is valiant and only put in just over a year ago...

You are topping the boiler up too high!!. Water when heated expands. You boiler has a pressure releif valve and this will discharge the water if the pressure gets to 3 bar. Vaillants can 'blow' at 2.7bar ;)

When the boiler is cold, top it up to 1 bar.

Don't think its the expansion vessel if its only a year old. Also pressure releif valves aren't faulty, if they leak its because of a pressure fault.

Make sure your filling loop valves are properly closed. Put your heating on full and watch the pressure gauge - does it rise above 2 bar??

If everything above checks out then there is a leak somewhere in the system and you will have to start checking -rad valves, pipes etc. There is a way to check if the leak is at the boiler but do the above first.

PRV's can leak if dirt gets on the seating of the valve, however, this is unlikely as the system is not that old.
Also, is the system fitted with an auto bypass? If it isnt and all radiators are fitted with trv's and shut off then this can also cause the pressure to rise.
These are just a few more suggestions to the ones already posted.
Hope it helps.

As dan says I know my way round a Baxi. Although I'd say its more to do with your system than your boiler. ring me if you would like me to have a look.

Mine was doing the same, it was a tiny leak in a t-joint where the solder hadn't quite sealed. Luckily it was found before the floor went in!