Midas, Myson BF Combi - Burner not lighting when C.H. on ...

[gerrard]

Combi boiler Potterton Midas , Myson BF ( 1993 - ALAH336).

Problem,
HW works ok, but CH does not. Pilot is lit up but main burner does not light.

Observations:
- Programmer´s internal battery is gone. I disconnected the prog.
- The pilot light ( should be on all the time) goes off after a day or two.
- System has been shut off for 3 years.
- I purged the radiators.
- Only device calling for heat is the electromechanical clock. ( that i can see)

Troubleshooting guide instructs to check 240V at external supply, timer and external control fault.

Here is my question. Do I need to have a working programmer ( external control fault?) for signal or is the electromechanical clock enough for the HC. It saves me from buying one and testing it to see if this is the root cause. Thanks...

 

[gas4you]

As long as you can present the boiler terminal with 230V as a call for heat I can't think it will make any difference as far as testing goes.

 

[namsag]

If it`s not been on for 3 years there is a good chance the heating pump has jammed, there is two pumps on this boiler.. If the power is coming out the mechanical clock to the programer then yes this needs to be working to complete the circuit back to boiler or bypass it some how if its bust

 

[gerrard]

If it`s not been on for 3 years there is a good chance the heating pump has jammed, there is two pumps on this boiler.. If the power is coming out the mechanical clock to the programer then yes this needs to be working to complete the circuit back to boiler or bypass it some how if its bust

namsag. I think I´ll get one and hook it up - although I can´t tell whether the clock is connected to the faulty timer. Thanks for the tip as well to look for a pump failure. If this does not work I guess I will check if the clock is at fault as well and check the 240V.

Thank you.