Boiler dosen't turn on!

[NickAW]

Hi,

Sometimes, about three or four times a week, my boiler does not turn on when the room stat calls for heat. I have to switch the whole system off at the mains, wait a few seconds, and then turn it back on. All is then fine. It seems random, and not caused by any particular event.

It's a fully pumped open-vented system, Potterton boiler. The stat is the programmable type, so the heating timer is set to on all the time. HW is set to certain times, not 24-hours. The system uses a mid-position 3-port valve. There do not seem to be any other problems.

Any ideas what could be causing this?

TIA,

Nick.

 

[mrgas]

Suprima boiler?

 

[Slugbabydotcom]

Could be diverter valve not working a microswitch. As the call changes from CH and HW to just CH the motor moves right across. When it gets to the CH position it operates a microswitch that makes the orange wire go live.
While you're in that box of wires that the DV is wired into check the function of the programmer by testing that the orange wire goes live with a call for HW only and the white wire goes live with a call for CH.
Check out your cyl stat. Turn the stat down past the click. The gray wire on the DV should then go live. [HW satisfied]

After that you could be looking at a boiler fault of some sort. Its a Potterton what?

 

[NickAW]

Hi,

No, it's a Kingfisher MF. Knew I'd forget to include something!

Regards,

Nick.

 

[gavinda]

similar issue with these... pcbs are a bit dodgy plus somethimes the gas valve fails taking the pcb with it but also the pcb can fail taking the gas valve with it.

 

[NickAW]

similar issue with these... pcbs are a bit dodgy plus somethimes the gas valve fails taking the pcb with it but also the pcb can fail taking the gas valve with it.

This exact thing happened last year. New PCB and Gas Valve were fitted. This particular symptom was not apparent last year though.

Regards,

Nick.

 

[gavinda]

remember my 1st mf... 3 days old... ff said change pcb. went back next day fitted new pcb, same fault . phoned potterton
have you changed the gas valve as well

no it say its a pcb fault

ah well you need to change the gas valve as well with this one

ah cheers, you're paying for both board btw