Boiler constantly firing

[nzmanc]

I have a glow worm boiler that suddenly is firing every few mins then going out. Ive looked at the pump and that is not working either. Unless im mistaken the boiler will switch off if there is no flow via the pump but why is it firing up in the first place. There is no demand for either CH or HW from the programmer.

 

[stevetheplumber]

I have a glow worm boiler that suddenly is firing every few mins then going out. Ive looked at the pump and that is not working either. Unless im mistaken the boiler will switch off if there is no flow via the pump but why is it firing up in the first place. There is no demand for either CH or HW from the programmer.[/
combi?

 

[nzmanc]

Sorry no its not a combi, regular boiler. When I switch in off then on again it fires up straight away, pump isnt running, even if i do give it a demand

One thing that may be connected. The two port valve to the CH is stuck in the open position

 

[stevetheplumber]

Sorry no its not a combi, regular boiler. When I switch in off then on again it fires up straight away, pump isnt running, even if i do give it a demand

One thing that may be connected. The two port valve to the CH is stuck in the open position

youve probably answered your own question change the valve see if that clears the fault

 

[REDSAW]

just change the stepper motor on the port.
screwfix if not local for about a £10er

 

[nzmanc]

stepper motor?? Do you mean the synchron motor. Ive checked that and there is resistance there which suggests that its ok. Im assuming if the valve is stuck open that will create a demand but the pump will not run??
Thanks all

 

[david williams]

motor valve jammed open aux switch in motor valve calling for heat, pump should cut in but is not ,boiler fires cant loose heat reaches set temp turns off ,check the wiring system

 

[nzmanc]

Thanks David. The wiring has been in place for a long time and no probs. The permanent live to the board is in via the clock which is unusual. Ive had it switched off overnight and turned it on this morning and all seems fine. If its a longer term issue i will replace the valve in full but that will be an issue in itself as it has been soldered onto the pipe into two tees unbelievably and access is difficult. Nothings ever straightforward 😕