Central heating issue

[terryplumb]

Are you certain that you are checking the actual PRV and condensate pipework ,show us pictures of those 2 pipes.
Something is amiss here ,if you are losing 0.5 bar pressure continually, hourly ,water has to be going somewhere .

 

[Langers_2011]

If you are losing pressure when the boiler isn't being used ,and nothing is coming out the boiler,it's condensate pipe,or the PRV's discharge pipe, that's indicative of a leak on the system. Is there any heating pipework buried in concrete flooring ,or a void under the ground floor?

I’ve filled it around 6 times now and pipework in the walls/ceilings would be very obvious. It’s a Maisonette too, so I don’t have pipes in the ground. Boiler is on the 1st floor.

Are you certain that you are checking the actual PRV and condensate pipework ,show us pictures of those 2 pipes.
Something is amiss here ,if you are losing 0.5 bar pressure continually, hourly ,water has to be going somewhere .

absolutely certain. I can see the condensate pipe at the bottom of the boiler, it goes straight out the wall underneath and that’s an outer wall. Same as the prv, which I’ve replaced.
There must be some old pipe that’s connected to the system somewhere doing something is my only guess. I had a leaking prv and bottle trap, replaced both of those and the pressure was holding. Now it’s worse than ever.
If I can’t find water, which I still haven’t, I’ll blank off the last two rads on old pipework at the boiler and just run fresh instead. Just baffling there isn’t any water anywhere.

 

[Langers_2011]

 

[Langers_2011]

I do have this pressure valve also. But I can’t unless I’m being stupid see how if this had failed I’d be dropping pressure like I am.

 

[CountryFan]

I do have this pressure valve also. But I can’t unless I’m being stupid see how if this had failed I’d be dropping pressure like I am.
View attachment 414532

No, that's a bypass valve

 

[CountryFan]

Have you checked at the prv before any pipework discharge?

 

[Langers_2011]

No, that's a bypass valve

Yes I thought that wouldn’t be the culprit, but best to ask

 

[Langers_2011]

Have you checked at the prv before any pipework discharge?

There is nothing from the prv. Was a small trickle before I replaced it.