Intergas 36 / 30 low central heating pressure.

[Bobjrc]

Hi I have an intergas 36/30 HRE that is showing low pressure but not all the time?
Had a problem with it that was diagnosed as a blocked pipe into the pressure chamber at the back of the boiler, the PRV valve was blowing off due to high pressure when the heating was running. This was cured by fitting an enternal pressure tank when the system was serviced. However, low pressure is now flashing again but only when the temperature rises?
First thing in the morning it is showing 3.1 bar this drops by min afternoon to 0.3 bar then rises again as the day cools down? I have checked the pressure at the expansion tank (with a tyre pressure gauge, air pressure above the tank) and this is always 1.5 bar. Does anyone know what the resistance should be for a given temperature at the pressure sensor? I think it is a faulty pressure sensor but it could be a fault with the PCB so that is why I am asking if anyone knows what the resistance of the pressure sensor should be.
Thanks Bob J.

 

[Razor900]

Cheapest thing to do is to install a filling loop with a guage built in and unplug the internal one

 

[Bobjrc]

Ok, will the central heating system run ok with the sensor disconnect?

 

[ianmcd]

Ok, will the central heating system run ok with the sensor disconnect?

yes it will, I have had some success removing and cleaning the existing sensor, depends how dirty the system water is

 

[Bobjrc]

Thanks for the advise. Fitted a filling loop with a gauge, disconnected the pressure sensor, ran the central heating up at full power ( house got a bit hot) pressure stayed constant.
Re checked the pressure this morning, pressure still reading the same.
Thanks again for the advise.