if u dont feel the coil enerjise say or hear the click

have u wired it up right ie the 2 oposite spades not the top as thats earth

and a good 24v suply

if it clicks and then u put gas in and it does not fire then thats another fault

and is it a 5404 ? burkert
or a cheap one it should say on it look at woodys page http://www.teamonslaught.fsnet.co.uk/co2_info.htm#valve