Gradual Leak on Heating System

NickJohn1911

Leak in heating system. Pressure over approx. 2 weeks will drop from 2 bar down under 1 bar necessitating the re-introduction of water into the system. I think I have isolated the zone where the problem is - downstairs radiators / pipework. As a FYI the other zones are Hot Water, Under Floor Heating in an extension, Upstairs Radiators. As I say I think problem is with downstair radiators / pipework. So far have spent quite a bit to try and isolate and fix problem:

1. One plumber convinced me to replace boiler. Cost approx. 8000 euros.
2. A guy who (allegedly) specialized in leak detection pumped gas into the system, came back next day and literally ran around the house with a gas "wand" and could not detect anything. He claimed that because leak is so gradual his system would find it difficult to pickup. Cost 500 euros.
3. Sealer introduced into system twice before new boiler - no joy. Cost 100 euros.
4. I purchased an inspection camera and have tried to detect leaks by inserting camera into a series of inspection holes - no joy.

Unfortunately, pipework in this part of the house is under solid oak flooring. For the most part there is a cavity and the pipes run in this space. It would very expensive to remove the whole floor.

Any suggestions on what else I could do?

Thanks

JamBur

I had a similar issue. It started as a very a gradual leak like yours. I went through multiple different leak sealers (Repa R 200 was the best of the bunch), but they were just a plaster on the problem. After a few years, the leak suddenly became a total loss of pressure within 15 minutes. No sign of damp anywhere, so it was fairly obvious that it was under my tiled solid downstairs floor.

I had a detection company come in and dig two exploratory holes. They were a useless waste of money tbh. They claimed that my pipes were buried too deep to detect a leak. This combined with the fact that even if they found a leak and repaired it, my downstairs loop was now full of crap whuch could mean other failures in due course. My only choice was to replumb my downstairs area. I decided not to dig up and lay new pipes, but instead to have some external pipes. Its very discrete, and nicely done.

Lenar3556

https://www.boards.ie/discussion/2058271313/gradual-leak-on-heating-system

No doubt you have looked into this already, but has an expansion issue totally been ruled out?

How many and what size expansion vessels do you have?

A system which doesn’t have sufficient expansion (because of faulty or undersized vessel(s) will discharge water via the PRV as the pressure rises - Sometimes this discharge is small and gradual enough that it not noticeable especially where the PRV is piped to outside.

Doolittle51

Good call on the PRV. One trick is to tie a ziplock bag around the discharge pipe for a while and see if any water collects in the bag.

But €8000 for a boiler replacement? wow

NickJohn1911

Thanks, will try the zip lock bag on the PRV on the boiler. There is a separate expansion vessel in the hot press apart from the one incorporated into the boiler. I assume the expansion vessel is okay in the new boiler. In general, is there a separate PRV for each expansion vessel?