Combi pressure query

Grampus8

Morning,

I had a new combi boiler installed in May. Had the heating on to test it at the time but hasn't been on since. Pressure was initially set at 1.5

Have been checking it periodically and it is currently at 1.1

As I said, we've only been using the hot water, not the heating; would this type of pressure fall be of any worry or is it relatively normal?

I had pressure issues with the last boiler hence the worry!

If someone could set my mind at rest (or not) that would be great.

Ta

Andy_WSM

This could be air settling out of the system (normal) or just the fact that the water around the system is cooler now, so the pressure has reduced. You will find the pressure fluctuates depending on the temperature of the system. It is designed to do this a pressure vessel is fitted to allow for expansion.

Grampus8

Thanks Andy, so nothing to worry out?

societys_child

No, sounds normal.

You could top it back up to 1.5 whilst the systems cold if you wish.

Andy_WSM

Grampus8 wrote: »

Thanks Andy, so nothing to worry out?

Nothing at all to worry about. You'll probably find the manual says pressure should be set at between 1 & 1.5 bar. In which case I'd have to disagree with societys child and not top up - problem is if you top up to 1.5 bar now it's colder, it could well reach 2 bar + when it's hot.

Grampus8

Splendid. Thanks all.

societys_child

Andy_WSM wrote: »

- problem is if you top up to 1.5 bar now it's colder, it could well reach 2 bar + when it's hot.

Yes, the instruction booklet should be consulted, only suggested topping back up to what it was originally set at by the installer

If it drops too low, it' could lock-out (mine states 1.5 and won't work when it drops below 0.5 bar)

Andy_WSM

societys_child wrote: »

Yes, the instruction booklet should be consulted, only suggested topping back up to what it was originally set at by the installer

If it drops too low, it' could lock-out (mine states 1.5 and won't work when it drops below 0.5 bar)

That's a fair point, but I have learnt over the years to never trust the "expert".

Always refer to manual. It's not normally wrong.