Vaillant Combi condesing boiler losing pressure daily no sign of leak

bambibashercol

You only need a foot pump like you would use on a car tyre.
The chances are that if the expansion vessel is ok and just needs repressurisng that you may still need to change the prv. These let water pass at 3 bar to stop the system over pressurising but once they have operated tend to still leak if there is any dirt in the system.

Lady_K

Going to get a relative to check the vessel as I wont be able get to it myself.

Can I just ask does the system need to be drained at all in order to recharge the vessel if the valve is ok? as I'm hoping it wont because new floors were put down a year ago

bambibashercol

nah its a straight forward job. If i remember the expansion vessel is in the right hand corner when the case comes off. If you get stuck then pop back.

EliteHeat

I hate to disagree but .......

Yes it does, but not completely. You can isolate the flow and return pipe-work under the boiler and use the boilers drain-off - not the pressure relief valve to zero the pressure.

When you pump it up, do it very slowly, really, really slowly until you get to about 10lbs of pressure on the foot pump gauge. Remember, the boilers pressure gauge will remain at zero.

Un-isolate the boiler and re-pressurise and you should be OK.

If you do not re-pressurise the EV whilst it is empty, you will have no idea how much pressure you are adding.

bambibashercol

sorry but i was presumed that it was 3 parts the way drained as it was blowing out the prv.
You need to take the top off the expassion vessle and if water comes out when you push in the valve then don't go any further as it will need replacing.

Lady_K

Or maybe its better doing it in the morning when its showing the f22 or f75 as wouldnt that be empty enough anyway?

bambibashercol

I got the manual knocking about somewhere in pdf. Let me have a look around and i will try and post the relevant bits for you.

C_Mababejive

Your location might be useful.

If you need to get a man/or woman in ...make sure you get a good one as you dont want just anyone spannering your nice Vaillant boiler. There are a lot of butchers out there you know.

Lady_K

Relatives coming to check in the morning so will find out if it can be recharged or needs a replacement pvr or whole vessel then, if it needs recharging he will want to do it then as he cant come back again

As far as cowboys are concerned I know by experience and vaillant are good boilers. I would want someone who has experience of them. A lot think they do know but they don't. I've had 4 plumbers round already that have just said its got to be a leak in the system and until I know where it is they can't do anything. Its also been serviced twice and those times I've told them about the regular topping up and they also didnt say anything other than it must be a leak. My previous boiler was a vaillant, I had it for 18 years and it needed topping up every 18 months so I kinow it shouldnt be like this

Oh yes and I'm in Nottingham area

thursday

I installed Vaillant last year by the plumber listed on their web site for my area (Central London). I think this is about the only way to stay clear of cowboys :eek:; ended up having rather nice straightforward guy who knew what he was doing rather well...