Combi Boiler Pressure Up and Down

[GonisDowr]

The pressure in my combi boiler (oil fired) seems to vary hugely.

When the heating is on it is at about 1 bar.

When the heating is off it can be as low a zero but then rises to 1 bar a few minutes after the heating comes on.

Other than this everything seems to be fine; both the heating and hot water are working well.

Should I top-up the pressure?

Cheers.

 

[exedon2]

Yes top up pressure
Pressure will always rise when boiler is on water expands when heated.

 

[Philip Morgan]

hello everyone, I'm having the same problem and not sure if the boiler is working as it should. I've not had a combi boiler before but it doesn't seem right to me. When the central heating is on the boiler pressure is up to just over 2.0 bar when hot water tap is turned on pressure drop a little then goes back up to where it was. This I know is normal but when heating is turned off the pressure drops to about 0.3 bar, if I then turn on hot water tap the pressure drops further. If I top up the pressure when heating is off to where it should be, turning on the central heating will increase the pressure into the red.
Hope this isn't long winded and you can understand what I'm on about, I've checked for leeks and all OK, boiler is a Worcester Bosch Greenstar. Any advice would be appreciated, Thank you.
Kind regards, Phil

 

[cjg]

you need to check your expansion vessel, poss needs recharge.

 

[Philip Morgan]

Sorry for the delay but thank you for your reply, will need a service probably as pressure is not right. Thanks

you need to check your expansion vessel, poss needs recharge.

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