Vaillant ecoMax 800

[papasam]

Got a slow depressurising leak. The drop from 1.5 bar to 0.5 took about 6 to 8 hours. Valliant engineer has found no leak on boiler and claims its in the pipework. I am not sure how he could detect a "no drop" in about half an hour when its so slow.
Trouble is its so slow that any water will evaporate on hot pipes as soon as it appears. I thought I could feel a bit of water around the PRV but he said it was from the condensate drip which is a load of fanny as its alongside and not below it. Anyway he claims to have replaced the PRV and washer but he still recorded a No fault Found which means that the insurance wont cover it of course.
The fact that the drop is slower when hot would seem to suggest an expansion differential eg copper against steel or brass and logically at the rads or taps and not soldered joints.
How does one check every joint in the house for a very slow leak. Its driving me mad.

 

[kevplumb]

stick the pressure on 2 2/ 1/2 bar

that should find it no higher tho

you could also try closing the isolaters under the boiler for a couple of hours

no drop it aint the boiler

when you open them if it drops its the pipework etc

 

[doitall]

Pull the caps off the rad valves and wipe your finger around the joints when the system is cold.

 

[mickyg]

you could also try closing the isolaters under the boiler for a couple of hours

i wouldnt recommend that on this particular boiler. Possible you might find yourself an increase in pressure loss afterwards

Stick a bag over the PRV pipe just to be sure about this. After 1bar loss you should have a decent amount of water in there.

 

[papasam]

Thanks all you sad bast**** with nothing better to do on a weekend. I appreciate it guys. Being an old retired engineer and general smartass who had been working with hydraulic valves and pipework before the Gas Safe wizard who checked my boiler was born ,I was pretty sure it was the PRV but he wouldnt have it. This afternoon in a mixture of frustration and intuition ,I gave the prv knob a fairly brutal tweak and release. It snapped shut smartly and bingo. So far so good the pressure has now been stable for 14 hours. Thank God I dont now have to check all my pipework. I appreciate all the helpful advice though guys ,this is a bonzer forum.

 

[kevplumb]

i wouldnt recommend that on this particular boiler. Possible you might find yourself an increase in pressure loss afterwards icon_wink.gif

crap valves mickey

 

[mickyg]

crap valves mickey

damn right. Not WB awful, but certainly the worst that ever came out of the vaillant factory.