halstead quattro gold lock-out problem

[chrised]

My Quattro gold boiler will start up, both HW and CH. After about 3-5 mins there is a soft clunk noise and the burner stops, green light goes off. Just like when it is up to temperature and no call for heat. Then after about 5-10 seconds the green light comes on, but no ignition, then it locks out. Pressing the ignition lock-out button after 15 secs results in ignition attempt, but no joy. After about 10 mins (when something has cooled down?) it will work again.
Help!!

 

[gas4you]

Can you tell if pump is running ok?

 

[chrised]

pump and fan both running fine

 

[gas4you]

When it is running for the 3-5mins are you getting proper hot water and/or heat to the rads?

 

[chrised]

Yes, all aspects of the system work OK. No evidence of overheat cut-off - no red light, no reset button popped out. ? ignition board??

 

[combiman001]

boiler cutting off in a few mins can be caused by a blockage in the fan venturie the pressure switch loses the variation in pressure.cure remove and wash out venturie