Pressue drop in boiler since en-suite upgrade. Advice pls

[Ltnman]

Last July we had the en-suite room upgraded. Work included laying down a new hardboard floor which was to stop the floor flexing as we were having a stone floor laid. The en-suite radiator was replaced and fitted on the adjoining wall. In November I noticed the boiler pressure was at zero. After that it was losing half a bar every 2 days.

I checked all the rads and exposed pipe work and could not find any leaks.
The boiler was serviced and no leaks were found. 2 bottles of rad seal fixed the problem and the leak stopped.

I have noticed that the pressure is very slowly dropping again. I suspect that a nail has gone through the pipe and the nail is slowly rusting which is why the leak has started again.

In November I emailed the bathroom company who did all the work informing them that I suspected that the leak might be due to them as I have never had to top up the pressure before. I asked them to keep this information on file as I had no proof they had cuased the leak.

Should I live with this problem or should I have the ceiling taken down below the en-suit so the pipe work can be checked?

If I live with the problem until it shows a damp patch how long are they liable?

 

[ChrisR]

Don't wait, act asap.
Many of us use endoscopes for this sort of thing. A small hole, or a number of them, through a ceiling is/are easy to fill.

It might help to make the leak worse, so you can find it. You can put the pressure up, to say 2.25 or so. It'll rise half a bar or so ( watch it) when it gets hot and you don't want it going over 3.

It may be possible to isolate the en-suite pipework to test it by itself?
Don't use any more rad seal, some boilers don't like it. The floor is probably flexing a bit, rubbing any nail or wiggling a leaking joint.

If they really used hardboard to "stiffen " a floor, gawd help you!