Boiler pressure

[Rover7895]

Hi people.

I've just moved in to a rental and the boiler pressure is too high (2.5 bar normal and 3.5 when heating on).

I've tried to bleed the radiators but hasn't really helped matters.

I got in touch with the letting agency and they just said the landlord assures them that the boiler passed the safety checks.

I'm a total novice and I don't know what I'm doing here but I don't dare put the heating on.

Any help would be appreciated.

[Someone-Else]

The pressure gauge shows the system pressure, so as you have said you should bleed the radiators, but you actually let water out not just air. Have a mug and cloth to hand. But do keep an eye on the pressure gauge, you don't want it to drop too much.

[ayjay]

so as you have said you should bleed the radiators, but you actually let water out not just air.

......boiler/pump, turned off whilst bleeding.

[Rover7895]

so as you have said you should bleed the radiators, but you actually let water out not just air.

......boiler/pump, turned off whilst bleeding.

Which one is the pump?

[PLB]

In your case if you turn the boiler off (Function Switch Set To 0) the pump will not run as it’s inside the boiler.

Set to 1.5 bar when cold.

The following is from the manual.

12.7 When the system is bled of any air it must be refilled until the pressure shown on the display gauge indicates a system pressure of 1.5 bar.

12.8 If the pressure shown on the gauge exceeds 1.5 bar discharge the excess pressure from the system via a radiator valve or pipe connection. Do not use the safety discharge valve as the valve seat may become contaminated with debris and fail to re-seal.

[Rover7895]

Ok I've bled each radiator and the pressure hasn't gone down. Still sat on 2.5 bar.

[Someone-Else]

Ok I've bled each radiator and the pressure hasn't gone down. Still sat on 2.5 bar.

bleed the radiators, but you actually let water out not just air.

[PLB]

Temporarily turn off the mains cold water feed valve underneath the boiler.
The one with the blue handle just to the right of the yellow valve.
Bleed a radiator, does the pressure now drop?
Report back to us.

[Someone-Else]

If you are thinking what I think you are thinking, would it not be better to remove the filling loop?
Also, would it not be a case of if you are right, would the pressure always be increasing?

I can not help but wonder has the OP let any water out? (other than the odd drip)

[PLB]

Sorry,
I should have explained.
I believe that a situation like this could be caused by a pinholed heat exchanger?
So therefore yes, filling loop valves passing was my next thought.
Re pressure increasing. It would increase and settle at whatever the property supplied mains water pressure happens to be. So that could be 2.5 bar in the op case.

[Rover7895]

Ok I've bled each radiator and the pressure hasn't gone down. Still sat on 2.5 bar.

bleed the radiators, but you actually let water out not just air.

7 radiators and filled half a bucket before I gave up as the pressure wasn't going down.

[Someone-Else]

Try it again, but turn the house water supply off first.