Boiler pressure help

[Simba-ali34]

Hello,

My boiler is a potterton pro max Combi boiler

The boiler pressure starts at 1 - 1.5 when the heating is not on. When the heating is switch on the pressure will drop to to 0.5 - 1 and slowly climb until it reaches just outside the 1 on the gauge.

Can anyone point me in the direction of what could cause the pressure to drop with the heating on as I would of expected it to rise.

It's probably worth mentioning that I've lost probably 0.2 bar of pressure over a 2 month period.

 

[Riley]

You will require a gas safe engineer to come out and take a look at your boiler it sounds like a couple of parts of it may need looking at and potentially setting correctly

 

[Simba-ali34]

Thank you for the quick response

I will organise a visit by a gas safe engineer.

To make sure I am getting the correct service from them, are there any certain parts or clues from what I've memtioned that i should make sure he is looking into correctly?

Regards

 

[Millsy 82]

I believe the pressure guage goes in on the negative side of the pump which is why your pressure drops when you turn the heating on. So I think it's fairly normal.

You may have a slight leak somewhere on your system/ boiler but trying to find .2 bar over 2 months will be like finding a needle in a haystack.

 

[Riley]

If you do need an engineer just explain what you’ve told us.

 

[Simba-ali34]

Strangely I have 2 thermostats on different floors of the house which can switch on the heating independently of each other

The situation I just described is using only the bottom floor central heating. If I switch on both sets of heating the pressure will increase to the same as when the heating is off (1-1.5)

I'll keep an eye on the decrease on the gauge and mention it to the engineer

 

[Millsy 82]

If your concerned about a pressure problem it should be fairly easy to check the main bits for a competent engineer will give you peace of mind.

 

[Avo]

Did you find out what this was

 

[Riley]

Did you find out what this was

No as the OP isn’t gas safe