Saunier duval exon....

[actualandy]

Hi, Had a call out today to a saunier duval exon. Besides a few horrific gas errors on install i have a wee problem. Boiler will not light, fan ok, pump and controls are all behaving.
Ignition clicks and solenoid seems to clunk! The APS is fine and venturi is clean. I have not worked on one of these before and i am suspecting a gas valve failure! any suggestions!? No gas at valve so can this be the board....cannot see a way to test the gas valve.
Any info would be appreciated.
Andy

 

[Gambino]

Does the pilot light ? If not, check the injector at the pilot is clear, two small holes can be cleared with small pin.
You say no gas at value, I take it you have a standing pressure, working pressure will not show until burner lights as first it only allows gas to pilot to prove rectification then opens valve to main burner.
The xeon is a Glowworm ultimate, download the fault finding for that boiler to follow, it may help you more.