Boiler pressure drops to 0 over a couple of days!

[timbeam]

Hi,

I have just recently bought a house which came with a Vokera Linea combi boiler already installed. Best I can tell it is about 10 years old.

The problem I have is that if I top the boiler pressure up to 1 bar, within 2-3 days the boiler will drop back down to 0!

I thought initially that this might be the PRV but after topping up and running the CH for 30mins or so the boiler only reached 1.5 bar and remained constant at that.

What confused me even more is that last weekend I went away for a few days and before I went I topped the boiler up to 1 bar. On my return the pressure was back down to 0! The heating was turned off and obviously no hot water was used either.

I just don't know where to go from here??? I'd rather not get an engineer out just yet if there are further investigations I can do first.

Surely I would notice if this amount of water was leaking from somewhere wouldn't I?

Thanks in advance for your help!

 

[doitall]

If the PRV isn't leaking outside then you have a leak.

Top the pressure up to 1.3 bar, then check all the radiator valves and any compression fitting for wet.

Pull the caps off the lockshield valves and check the packing glands.

 

[timbeam]

Thanks, I'll try that.

But like I said above, would I not notice a leak sufficient enough to reduce the boiler pressure to 0 in just 2 days?

 

[doitall]

May be running down a pipe, you don't have a big leak.

 

[timbeam]

Hi Guys,

Right, I thought I'd post an update after having followed doitall's advice.

The PRV isn't leaking, neither are any of the radiators. It would appear that the leak is coming from the boiler itself, evidenced by a dried water mark under the boiler!

Having said that, it no longer seems to be nearly as bad as I originally said above. It is lasting much longer now before it loses all of its pressure, in excess of 2 weeks.

I realise that it is extremely difficult to distance diagnose a fault like this but for those of you who are familiar with the Vokera Linea range of boilers, any ideas what could be the likely cause? Leak from the heat exchanger? Rough costings for repair?

I realise I'm asking a lot but I would really appreciate all your opinions before getting someone in. It's always difficult to know who to trust and I'm trying to work out whether this boiler with all its recognised faults is worth repairing or if I should just cut my losses and replace it.

If you think it's a good idea just to cut my losses, any suggestions on a good replacement for a Vokera Linea 24?

Cheers all!

 

[timbeam]

Any more advice?

Is it worth adding some Fernox leak sealer?

Please help!

Thanks.

 

[ChrisOxford]

There are loads of places in any boiler which could leak. Some would be extremely expensive and hard to fix, others dirt cheap and take about 10 minutes.

Apart from the pressure relief valve (PRV) which you've checked, another "classic" potential leak point in a sealed system is the automatic air vent (AAV), and I would check that first. They look like this, usually: http://199.253.127.83/ProductPages/97_vent.jpg

Have you got the manufacturer's instructions?

Note that lots of boiler repairs CAN be done as DIY in your own home, but ask advice here if uncertain.

C.

 

[timbeam]

Hi Chris,

Thanks for the suggestion.

I do have the instruction & installation manuals which is handy. I've been putting off taking the cover off of the boiler and having a look but I think that is the next logical step.

Once I've done this I will post back with any extra info I find.

Thanks again!

 

[ChrisOxford]

Disconnect the mains power before you do.

Don't mess with anything that's not related to the fault, and make sure everything goes back EXACTLY the way you found it. If you have leftover screws or are in any doubt, you MUST call a RGI out to help.

It's also strongly advised that you do NOT take off the combustion chamber cover.

A torch will be very helpful.

Let us know how you get on.

 

[timbeam]

I've not had chance to take the cover off of the boiler yet but I have had some additional problems since last posting.

For some reason, when the boiler is heating the hot water, it also warms the radiators - odd but not alarming. More worrying was last night. First time the CH has been used in a while. It was set to come on using the integrated timer in the boiler. All worked as expected until it came to going to bed. Even though the boiler should have turned itself off, I noticed that it was still making a lot of noise and upon inspection the boiler was still running, appearing to heat the water. But the display was showing a water temp. of over 90 degrees!?!?

I assume all these problems aren't related?

I think I already know the answer but do you think I should just get rid and install a new boiler?

Someone I've used before is recommending a Worcester Bosch as a replacement with a 7 year warranty. Is that a good option?

Thanks for all your help, this has been quite a saga!

 

[ChrisOxford]

I think I already know the answer but do you think I should just get rid and install a new boiler?

No, I would get a proper heating engineer to look at it first. It could save you an absolute fortune.

A lot of "really bad" symptoms can be caused by simple faults, and vice versa of course.

 

[timbeam]

I know what you mean Chris and I will of course get someone to have a look and quote for fixing it before resorting to a new boiler but after reading some of the horror stories on here re the Vokera Linea boilers I don't want to just waste money on a poor boiler.

 

[ChrisOxford]

True. I'm no expert on boilers, so your fears may well be justified.

 

[Agile]

I dont know why you are so fearful of calling an engineer. Those TV programs are just actors making something for entertainment purposes only.

As it does seem to have a fault as well as a leak then it might cost about £150-£250 to fix it.

A replacement boiler could be £1200-£1800 !

The Linea is a fairly modern boiler and properly installed and maintained they are reasonably reliable.

Tony

 

[kevindgas]

first thing to do is go back to the very basic test!.

if you can leave the boiler for a day then great, top up pressure to 1 bar+ remembering what figure you stop at. then turn off the radiator circuit isolation valves under the boiler. if pressure remains stable then the leak is in the system. if it drops then the leak is in the boiler.