Water Leak.

[jgmgasservices]

Got called to a job, Baxi Duotech pressure dropping, checked expansion vessel and was flat, re-pressurised to 1bar disconnected prv and tested up to temp, all fine, no leaks on boiler. left at that.

Got a call back still dropping pressure, checked vessel again all ok, disconnected condensate to check heat ex all ok. Checked all rads all ok. No leak in boiler Pipes ran in concrete floors which had been dug up 6 months ago to fix CW pipe that was leaking.

My advise was to try leak sealer but they didnt want to as was convinced it was under concrete floor and said it must be guarenteed by guys who repaired CW pipe.

So they got a company with thermal cameras and loads of equipment around, who spent the full day there and came to the conclusion it was expansion vessel. Customer now very upset with me. So over the phone i got him to tie a bag round prv and turn heating on and ring me in a few hours. Called me said pressure didnt rise above 1.8 and bag bone dry, so I explained not EXP VES. when checked this morning pressure had dropped ( bag still dry).

Customer not convinced so went today with new vessel changed that and prv just to satisfy them, checked old vessel when removed which had 1 bar still.

So what I am am asking is any ideas what it could be?

Sorry for long winded question.

Cheers

 

[arran197]

Did you run the boiler with the condense pipe disconnected? I'm just wondering if the heat exchanger only leaks when warm and then it's going down the condense pipe. Sounds like a leak somewhere to me though. Thermal imaging can't be that food for this kind of thing surely? If it's trickling out it could be cold and it wouldn't get picked up.

 

[jgmgasservices]

Was thinking that about heat ex I've never had it only leaking when warm. So if this was fault how would i detect this as condense would be running anyway when warm.

 

[arran197]

Get the boiler warm then switch it off and isolate it from the flow and return. You could do that anyway to prove it's not the boiler. If the pressure doesn't drop then you know the boiler isn't the problem.

I'm guessing it's a leak somewhere as what you have done so far seems to be good and would almost eliminate the boiler anyway.

 

[goz666]

I would pressurise to 1 bar then isolate the flow and return under the boiler to prove one way or another whether the rads/pipework is leaking or the boiler and go from there. If its still dropping then as Arran says disconnect condense and try that. Also when the boiler is running is the pressure stable or going over to 3 bar ?