Advice would be appreciated

[Davidtheg]

Update this morning.....

Last night i pressurised the system with all but the rad in the bathroom shut, I then went round all the radiators in the house one by one opening and running the heating and the closing the valves until I had down all the rads and the pressure stayed in the system. Confident with this I then opened all the rads and left running on timer overnight but I’ve just got up and it’s lost the pressure. I don’t understand why the system would hold pressure with each radiator opened individually but then lose the pressure with all rads opened??

 

[terryplumb]

Maybe its a slow weep ,exacerbated with expansion / contraction of pipework. Do you find you have to bleed a lot of air out of rads when pressure drops ?

 

[Davidtheg]

Yeah there usually is more air in system after it’s dropped.