I recently moved into a house which has a really old natural gas fired hot water boiler (repco) The pressure on the gauge goes up to 40-50psi if I don’t manually let out some water from one of the zones.
The pressure relief valve seems to be blocked by the wall (maybe boiler moved closer to the wall over time?)
I recently replaced
- the pressure expansion tank,
- air vents
- pressure reducing valve
- pressure gauge on boiler
When I bleed the zones, the pressure drops to 12-15psi, but after 4-5 hours it goes up to 40-50psi.
If the pressure relief valve wasn’t blocked by the wall, I think there would be a constant flow of water coming out.
Does anyone know what would increase the pressure over time other than already replaced parts?
2 plumbers already looked at it but couldn’t figure it out.