Gas boiler intermitent ignition

[Raynard]

Ideal Elan2 gas boiler sparks up, runs for a few minutes then cuts out and won't restart until a few hours. Switching off/on at wall socket CH & HW lights on programmer are on, No indicator light showing on the on/off boiler switch next to Hi/ low switch. No pilot light, no ignition spark.
New PCB (6 months old), previous contact switch on PCB burnt out.
Pump spindle is rotating when boiler does fire up.
Can anyone tell me What do I check next?

Thanks in anticipation of your response

 

[kevplumb]

is the heating / hot water warming up at all

 

[Raynard]

Room stat set to max, digital programmer CH set on constant,CH light on programmer but boiler won't light. Set HW on programmer to constant boiler fires up (but only for a few minutes) So I guess I have hot water but only for a few minutes
System bled, no air locks.....

 

[kevplumb]

water aint going round either the pump is b***ered or the three port valve is of the motorised type and is stuck

 

[Raynard]

Thanks Kev,
I had tried the Motorised Valve before by moving the lever by hand it was moving across ok and returning back to auto, so had discounted this.
I have now secured this in the manual position turned boiler on, no ignition when prog set to constant calling for CH. Boiler comes on when set for HW.... rads now getting hot....
Slower than usual. Would that indicate both the pump and the MV have problems?

 

[kevplumb]

take the actuator off the valve and make sure it moves when you select hw only or ch only the lever locks it mid position so its splitting the load

 

[Raynard]

I removed actuator from 3 port MV, this does not move when CH or HW selected but does move manually.

 

[kevplumb]

would think youve found your problem it should motor to position depending what you have on ie water /heat/or both

 

[Raynard]

Cheers, all sorted so we have got heating again. It was the MV, hard to operate. Replaced both MV and actuator.

Thanks for the advice Kevplumb

 

[kevplumb]

no probs

 

[namsag]

You psychic then kev without original post mentioning it you guess it has a 3 port motorised valve (2 two ports more common) with a removable actuator . and the response from a diyer is not to ask what an actuator is but to remove it staight away and start using a term like MV which the pro`s use . also 3 answers within a couple of mins 0f question being asked . surely my suspisions are wrong and your not feeding questions to your self

 

[kevplumb]

well off the mark m8 3 port more common up here
never took that much notice

add the fact that it wouldnt be the first time id dived in and regretted it

 

[Raynard]

Kev

The next question will cost more £...

Can I have that fiver now

 

[kevplumb]

cheque is in the post m8