glowworm ultimate 100FF boiler re-fire every 30 seconds.

[mazkhan]

I have a Glowworm ultimate 70FF 70000btu boiler about 6yrs old. It fires up ok initially but keeps cutting out and re-firing about every 30 seconds and continues to do this until I shut it down. The fan appears to be running ok and flue is clear. Removing the front cover allows it to run continuously most times. Advice would be gratefully received. I hate not to be able to fix something myself!. Neon light 4 keeps going on and off every 30 seconds. Checked pcb, air pressure switch, fan and all are fine.

 

[gavinda]

for starters , please dont leave that cover off. it sounds pressure related, are the actual tubes ok to the aps. and is the flue outlet clear... ie. notheing groeing over or obstructing it?