Volkera Excell 80SP

[RJW]

I have recently moved into an old property with a central heating system containing this "quality" boiler.

I found a few TRV's leaking and bleed valves so I changed them all out, and now I have heat again with no air in the radiators.

The boiler is still dropping pressure.

If I pump it to 1.5 bar it will be down to 0.5 bar within 48 hours. There are no obvious signs of any leaks, so I'm not sure what to do now to resolve.

Anyone any ideas???

 

[kevplumb]

check the prv

I have recently moved into an old property with a central heating system containing this "quality" boiler.

dont let DP hear you

 

[RJW]

Thank you for the advice.

I'll put a bag over the end of the pipe that goes to outside, and pump it back to to 1.5 bar again, and see if I get a bag of water.

I'll let you know.

 

[RJW]

kevplumb: i'm back...... update.

No water coming out of PRV that I can see. The bag was not full, anyway.

"Kettling" noises have started now. So im gonna have to flush it.

Its loosing half a bar every 24hrs.

Any other suggestions??

 

[nickso]

heat exchanger could be leaking. you wouldnt see any water, not until it bursts that is.

 

[superdupergasman]

The Heat exchagers tend to leak on either end inside the combustion area. If you look through the window upwards when boiler running and the OUTER WHITE case is off (NOT THE INSIDE ONE) you may see black soot forming, early sign of a leak.

Have you checked all external pipework.....defo no leaks under floor....and also drain point for system is not dripping??

For the Heat Ex you will need to get a suitably qualified man to do the job.

 

[DP]

'Black soot' forms on left hand side and to lesser extent, right hand side, (along with dust settlement and eventual blockage) due to primary return being a lot ccoler (hence condensation of POC). I have never seen this black deposit where water exits the heat exchanger.

I would be checking for leaks at the heat exchager unions and examining the insulation panels (evidence of leaks) for signs of leaks. But this is CORGI area so keep out. Union seals leak because people keep turning the power selector to OFF while pilot stays ON

 

[RJW]

Thanks for your help guys!!!

I forgot to mention that I have isolated the flow and return on the pipework that I can't see (under the living room floor), to see if the problem goes away. Isolation ball valves are great!!!

Therefore, by a process of elimination, the leak is coming from inside the boiler somewhere. I'd better call a CORGI man in to be on the safe side. Excluding labour, does anyone know a rough cost??? Considering the boiler is worth about 3p.

It would not surprize me if the thing is full of soot. The property came without any loft insulation, and most of the loft was covered in the stuff. About an inch think. I looked like a chimney sweep after an hour.

 

[nickso]

vokera h/e's are easy to change. shouldnt take an experienced guy anymore than 40mins.

 

[RJW]

Hi

The heat exchanger is dry, and looks OK apart from the muck and fluff.

I've put some cleaner in the system, which has stopped the kettling noises, and capped the auto air vent (last resort).

I thought I would still be able to bleed through the upstairs radiators?

The problem has suddently vanished.

Is it possible that the auto air vent is faulty, allowing water to leak onto the exchanger and evaporating??

 

[gas4you]

Yes, AAV's are notorious for leaking in any make of boiler and should always be one of the first things to check if the pressure drops consistently.

 

[superdupergasman]

or the leaking water has become crusted up and plugged the leak.

the AAV should be replaced which is an easy job and the cap left open or you'll get bother with the pump failing next!