Potterton promax ultra 33erp not responding to thermostat

[Rick H]

Hi sorry if this has been asked before but does anyone know if its safe to use the de-aeration function of my boiler a few times to temporarily heat my system.
I'm waiting on a second technician visit tomorrow as one who visited didn't have experience with Myson thermostats.
My boiler works for hot water but setting either of the thermos doesn't trigger the heating I've tried soft and hard resets for both thermos and boiler with no effect and there's no error codes on display the pressure is correct,return flow and temps all ok so assuming pcb has got a problem or some receiver circuit issue.

I have run de-aeration a couple of times now to heat radiators but it sounds like it's pushing the boiler to the max doing this any suggestions to get it to bypass the thermostats temporarily any other way that's not going to wreck it would be greatly appreciated.

 

[CBW]

I think you possibly mean chimney sweep mode? It’s best not to keep doing this as it’s putting it into max burner rate every time. Which Myson thermostat is it? Does it take and or need (good alkaline) batteries? Are any clocks set to constant/timer?

 

[ianmcd]

That is service mode and over rides all the controls, it is your thermostat that is at fault, post a pic of your thermos and the front of the boiler