I've had a whole new central heating system installed, with an unvented hot water cylinder and underfloor heating, and ever since installation, boiler pressure has been dropping. The installer got through the guarantee period by telling me that it was air in the system, plus in the summer when the CH is off, it can hold for months at a time, but when the system is being used a lot the pressure drops by 0.5 bar over a few days and then the boiler switches off.
Over the past couple of years I've had various people look at it (original installers, UFH leak specialist with gas tracing) and I've been told by everyone that there might be a leak somewhere as there is nothing coming out of the external overflow outside the property and the water has to be going somewhere. But no one has been able to locate a leak.
Some tiles started lifting up on the ground floor and I thought that must be it but then when I had someone in with gas leak detection kit in he pulled up the tiles and broke up the screed, but the underfloor pipes seemed to be intact. So the floor was all messed up, water everywhere, but no leak to be found. I then identified a leak in a shower (behind the wall tiles) that was likely responsible for most or all of the water that caused the tiles to lift. The only *other* place that I could see any water coming out of anything else was the air release valve on the hot water cylinder, but I thought that the cylinder was for the dhw not the ch, so didn't think this could be related.
So I was stumped for another 6 months or so.
Eventually I came across some forum posts suggesting that some folks had put dye in their CH water to identify leaks. So I got some non toxic UV dye and put it into the filling loop when I (again) had to top up the CH pressure.
Suddenly I found to my surprise that there was indeed CH water coming out of the automatic air release valve on the cylinder - and there was a lot of it!
(Note the pink droplet on the top of the auto air separator and another one hanging off of the side of it - which may have leaked separately - and also all the pink below. The toilet roll that was down there had been drenched in pink CH water!)
I'm not sure why that would happen, but now I know, I'm also not sure how to go about fixing it. Should the CH water be there in the first place? Do I just need to get my air release valve replaced or is this a symptom of a bigger problem?
Many thanks for any advice
James
Over the past couple of years I've had various people look at it (original installers, UFH leak specialist with gas tracing) and I've been told by everyone that there might be a leak somewhere as there is nothing coming out of the external overflow outside the property and the water has to be going somewhere. But no one has been able to locate a leak.
Some tiles started lifting up on the ground floor and I thought that must be it but then when I had someone in with gas leak detection kit in he pulled up the tiles and broke up the screed, but the underfloor pipes seemed to be intact. So the floor was all messed up, water everywhere, but no leak to be found. I then identified a leak in a shower (behind the wall tiles) that was likely responsible for most or all of the water that caused the tiles to lift. The only *other* place that I could see any water coming out of anything else was the air release valve on the hot water cylinder, but I thought that the cylinder was for the dhw not the ch, so didn't think this could be related.
So I was stumped for another 6 months or so.
Eventually I came across some forum posts suggesting that some folks had put dye in their CH water to identify leaks. So I got some non toxic UV dye and put it into the filling loop when I (again) had to top up the CH pressure.
Suddenly I found to my surprise that there was indeed CH water coming out of the automatic air release valve on the cylinder - and there was a lot of it!
(Note the pink droplet on the top of the auto air separator and another one hanging off of the side of it - which may have leaked separately - and also all the pink below. The toilet roll that was down there had been drenched in pink CH water!)
I'm not sure why that would happen, but now I know, I'm also not sure how to go about fixing it. Should the CH water be there in the first place? Do I just need to get my air release valve replaced or is this a symptom of a bigger problem?
Many thanks for any advice
James
