if it does not light in 7 seconds the red light comes on, I had this problem and it was due to a sticky gas valve from the ethylene glycol transco put in the gas supply.
I fixed it in five minutes by putting a hair dryer on the metal body of the gas valve to get it hot and turn the glycol wax into vapour then run the boiler to fluch it out. It worked great after that and I fixed a problem that an expensive plumber had not been able to fix.
Paul, April 2009