Honeywell S8610M Ignition Control not sensing flame every third time.

8ttam2

I've got a Mini Gas boiler that heats my house and noticed that the flame sensor will go into reset mode about every third time. Two out of three times it will spark, sense the flame, and the burner will fire up. On the third time, it will trial for spark for 15 seconds and then shut off without kicking on the burner. The led light will flashes 4 times.

After 5 minutes, the controller will reset and the burner will usually kick on the second time. By this time the water temperature is under 120 degrees. On the next cycle the igniter senses the flame and the burner will fire up as normal.

I pulled out and cleaned the igniter rod and it did not solve the problem. The ignition control manual says to replace the gas valve and if the problem persists to replace the controller. I can see the pilot flame and it looks ok, so I don't think the gas valve is the problem.

Is there anything else I should test/check before replacing the ignition control module?

JUGHNE

Is the igniter rod a hot surface igniter, (glowing red hot) or a sparker.
Do you have a separate flame sensor rod?

And always a good clean ground connection from the burner to the module is necessary. Pull and reseat any terminals.