Boiler Pressure is falling after top-up

[inod]

I have just completed a small piece of work as follows.

1. Turned off boiler
2. Turned off gas
3. Turned off mains
4. Drained down system
5. Addded a new radiator to the system
6. Turned on mains
7. Topped up system (and bled radiators) to 1.25 bar.

I left the system without gas, with eletric turned off, and mains turned off overnight. I have just checked and seen that the pressure is 1 bar.

This has happened two nights in a row.

There does not appear to be any leaks anywhere (floorboards are currently up, and the new radiator I installed seems sound).

Does anyone know what the problem might be?

 

[gas4you]

Could just be air in new water escaping via auto air vent in boiler or elswhere if they are fitted. Any drips out of prv pipe? You didn't drain down via prv did you?

 

[inod]

Hi Dave

I'm not sure what prv means is it the overflow pipe from the combi?

I actually drained down from one of the ground floor radiators which has a special connector, to which I could attach a hose pipe to, then I turned the square nut to release the water.

I thought that there might be air in it, but last night I bled all of the radiators, and water did seem to immediately want to come out when I tried to bleed each of them.

 

[inod]

P.S. I assume that it doesn't matter that the electric or gas isn't on (My sparky has curerently disconnected the switch, cos it is moving a few inches, and I am awaiting hios return this weekend).

 

[gas4you]

Yes the prv is the pressure relief valve. This terminates outside in the 15mm copper pipe. It is not an overflow and should never drip.

The air wouldn't necessarily be in the rads.

I think you may be a little premature in worrying about this. Wait until the electric is back on and the combi has circulated the water trhought he system and been heated for a couple of hours or more. It could just be settling down. Worst ones I've had ahve lost entire pressure over weekend and no leaks present. Just need topping up and all was well again

 

[inod]

Thanks Dave

I'll wait until the eletric is back on and keep my fingers crossed.

Thanks for your help.