7 year old Ariston combi-evo boiler; never had any problems so far with it.
Had a boiler service / gas safety check in April, all fine and dandy, didn’t turn the CH on until yesterday. Boiler sounds fine, no errors or new sounds, all rads piping hot. I bled the rads before hand, no trapped air. Refilled the pressure back to 1.5 bar; it’s been 1.5 bar since the boiler service, hasn’t dropped at all in 7 months.
Put the heating on for an hour to test it, pressure went up over 3 bar (red line) which was concerning. Next morning, pressure was down to 1 bar so .5 bar dropped. Bled rads again (no air), refilled to 1.5 bar and did another hour of CH, exact same pressure drop.
I had a look outside whilst the heating was on at the small old copper pipe on the wall thinking it was the PRV pipe but not a drop coming out (it looks decommissioned). The water coming out of the condensate pipe into the gutter however looks a lot more than usual, but I could be mistaken. Does anybody know if the PRV could be draining into the condensate pipe instead?
There’s no obvious plumbing leaks anywhere, pipework seems sound, and given how much water I’ve had to refill, I think I’d see a damp patch by now (I even used my heat FLIR cam on the ceilings and no damp / cold areas at all).
I put a nail in a pipe years ago and the pressure dropped to 0 bar within 10 minutes even though it was a tiny hole so I doubt it’s a pipe leak issue. Boiler pressure only drops again after central heating is used, showers and taps running hot with no effect on pressure.
Sorry it’s a long post, just wanted to pre-empt any questions I might get asked. Getting the boiler guy back out this week, just wondering if anybody can add any suggestions I haven’t thought of yet?
Cheers 🙏