Hi everyone. This is my first post here so hopefully someone can help.

My oil-fired boiler has developed a problem which is becoming more and more frequent. For information the boiler is fitted with an Ecoflam Monoflame Minor 1 burner.

When the burner starts it is supposd to run the motor and fan for a few seconds to pre-purge the systm before trying to ignite it. Sometimes this is not happening. What happens instead is that the burner just sits there making a buzzing noise. No motor run, no fan - nothing apart from the buzzing. After about ten seconds of this the burner goes into lockout because it has not seen any ignition.

I have found that if I hit the burner assembly fairly hard with my fist I can usually get it to start running.

Also, I've only just really started experimenting but it would appear that the problem is temperature-related. For example, the boiler has been playing up all weekend but tonight I started running it at setting 3 on the boiler thermostat with the front panel off and it hasn't missed a beat. I have (literally) just turned it up to 6 (maximum setting) and left the front panel off and so far all appears to be OK.

I have done a bit of research myself and the prime suspects seem to be either the motor or the motor capacitor. The fact that the motor won't start makes me think it is the capacitor, but the fact that I can fix it by hitting it makes me think it is the motor getting stuck!

Any thoughts from someone who really knows their stuff?

Thanks in advance.