have you cleaned the venturi and checked you flue is unobstructed both inside and outside (check the terminal)
T
March 2008
if it works with the cover off it must be atmosphere problem. with cover on it lights up then goes out lights up then goes out. cover off it stays alight. all i can think of is blockage or aps. sorry i cant be any more definate. things are alot easier when they just dont work at all :-).