Central heating pressure loss problem

[eloise612]

My grandparents are having a major headache with their heating. They bought the bungalow recently and have had the following work done:

The previous system was removed - the CF wall boiler, flue, cylinder, expansion tank and pipes not in use, lounge radiator rear the kitchen and capped pipes close to the floor.

New Worcester Greenstar 25si combi boiler installed on 11 July.
Power flush 14 July.
Checked 25 August
Boiler topped up (repressurised) 1 September as pressure dropped
Pressure dropped 7 September - heating engineer called and they suggested there may be a leak
Pressure down to zero 16 September
Heating engineer isolated boiler, left on 1.5bar 19 September
Boiler remains 1.5 bar 20 September
Heating engineer checked on 23 September, no change in pressure, advised not boiler problem.

Trace and Access specialist (ADI Leak Detection) - repressurised boiler, traced pipework using thermal camera, no problems detected. Drained system and pressurised with tracer gases at 2.5 bar for over an hour. Found no drop in pressure. Checked radiators and found most loose and new radiator very loose on fittings so they tightened them. Refilled system. Inhibitor and Leak seal re-added to system.

30 September Worcester Bosch engineer - switched off central heating section, to check pressure - isolated boiler, pressure did not drop over 3 days. Unable to check entire boiler as part of kitchen needed to be removed for access.
Worcester engineer revisted 4 October - fitted new heat cell to eliminate boiler from pressure loss on system, had boiler on test for 4 days, no drop. Checked expansion vessel and P.R.V all ok. Pressure left at 1.5 bar.
By 5 October the pressure had dropped right down to the red section, by 6 October it was back at zero (previously pressure dropping over 3/4 days).

Does anyone have any ideas please as we're running out of ideas and this has been going on a long time now?! There are no obvious damp areas or leaks but all the pipes are beneath the concrete screed floors. Shouldn't the leak detection have found any leak if there was one and it was done properly? Has anyone got any experience of the company used (www.adileakdetection.co.uk)?
There were a couple of replacement radiators installed with the new boiler but 5 existing ones remain.

Thanks in advance!

 

[DeltaT2]

My heart goes out to your grandparents, people of that age shouldn't have the grief.

I'd first look at the old radiators & old radiator valves, sometimes you can get microleaks, small leaks that just evaporate. It does sound as if you have eliminated the boiler as being the problem though.

If all else fails; Roger Servotech can put some milk in it.............Sorry, that's just a wee private joke.

Sort of golden rule with sealed systems;
Quick drop in pressure, easy to find leak.
Slow drop in pressure, hard to find leak.
Double check these radiator valves.

 

[blueagle78]

Trace and Access specialist (ADI Leak Detection) - repressurised boiler, traced pipework using thermal camera, no problems detected. Drained system and pressurised with tracer gases at 2.5 bar for over an hour. Found no drop in pressure. Checked radiators and found most loose and new radiator very loose on fittings so they tightened them. Refilled system. Inhibitor and Leak seal re-added to system.

Its an old post but I just want to share my experience with ADI. Not much different than this one. I personally think they're useless and one should avoid them. I've got major leakage but they didn't find anything the first time. Told me it could be my boiler so got boiler checked and as expected boiler wasn't an issue. Called them and they gave me a lot of grief before they sent the guy out again. He found the leakage only because it was evident from wall being damp. I paid them for leakage detection and fixing but they refused to repair stating they had to send leakage detection guy out twice so they'll charge extra for repair.

 

[Nishikigoi]

Issue with www.adileakdetection.co.uk seem to be pretty common, particularly not finding the leak and using leak seal.

We have a customer in Thame who had these issues and ADI Leak Detection used leak seal and ruined a new boiler, refused to come back and had pretty much the same situation as Blueagle78. He though it was old in 2011 and it's nearly 2015 and the problem is just the same!

Google them and I cannot find an address that matches company house and all the addresses are PO boxes in business centres or a 'towns' not street addresses as they should be.

Might be an idea if a few people find their Google map spam addresses and click the 'report a problem' button, I know you can also leave reviews on google too and that might warn others off!