Alpha CB24 Combo Boiler Pressure Problem

[AdrianB]

Hi all,

We have an Alpha CB24 Combo boiler in our flat. Since we moved in, in May we haven't used the heating just used it for water which its fine. The pressure shows as about 0.6 bar which is in between the red and the green. However I turned the heating on and it dropped straight into the red zone so I turned it off immediately and it went back to its usual 0.6 bar.

Can I raise the pressure myself considering I don't have any plumbing experience or am I going to have to get a plumber?

Also this might be a bit silly but do combo boilers use thermostats as in the things on the wall where you set the temperature. We have two very old looking ones right next to each other in the hall but they don't seem to do anything.

Thanks.

 

[Bahco]

It is normal for your pressure to rise when heating is on due to expansion.

Do not worry unless the pressure reading goes above 2.5 bar which will be excessive. At 3 bar your relief valve will open, letting out water.
Consult your boiler manual for the correct cold pressure.

With regard to your stats, you may have one for upstairs and one for down, which enables you to set temps for each zone.
Have them checked if you feel they are not working. If you set them at 18 degrees, they should cut off the supply to zone when room temp hits set temp.

 

[AdrianB]

The thing is the pressure falls when I turn the heating on. It falls into the red zone for low pressure.

I cant check the stats till the boilers sorted as I don't want to damage it running in the red zone but it just seems strange having them both next to each other.

 

[hobhead]

Check to see if water is coming out of the release pipe ( outside the property) when you put the heating on, are you topping the pressure ie filling the system up? If so then likely to be expansion vessel charge or needs replacing.

 

[Bahco]

He may be ok now!

 

[hobhead]

Oops!