EcoTec Plus F75 fault what to do first?

[ericom]

We increasingly experience F75 fault code. Initially this only occurred when we had left the house for a week on holiday and was reset by simply re-booting.

When this didn't work, on one occasion I found that bleeding a little air out of a radiator changed the pressure sufficiently to clear the fault on re-boot.

Now the fault is occurring more frequently and once even when the boiler had just sat overnight. It is summer so we are not using heating at present.

So far I have found that a small top up of water pressure to the CH system using the flexi hose will clear the fault on re-boot. I should say that the pressure in the CH system seems to hold up okay.

Because a slight pressure change appears to help, I have assumed that the sensor may be sticking and requires replacement.

Is this a fair assumption? If not what?

Thank you!

 

[picasso]

The pressure sensor would be my first check, they are about £20 so worth doing first.

 

[Dan Robinson]

Which of course means opening the combustion chamber, so rgi territory.

 

[picasso]

Would you class taking the front casing off as opening the combustion chamber?

the water pressure sensor is in front of the canoe filter.(as I am sure you know)

 

[Dan Robinson]

I know what you're thinking. .. but in this case (arf) yes.

All sorts in there to get nudged


*edit


Or if the case isn't put back correctly and the last service man had his fga set to Lpg by mistake ... The combustion could be all over the place