Hello,
We have had one of these ovens for about 10 years and have had the same fault. Not once, not twice.......... not, oh bugger it I forget how many time we have had engineers out to put it right. At least once every 12 - 18 months. Apparantly it is caused by; not enought air getting into the oven, too much air getting into the oven, the thermo cupling, the circuit board, the thermo cupling agian, a perished wire................bored now. After 5 call outs in 1 month this year, and the ignition still ticking, it was deemed uneconomical to repair any more. Thank god we had insurance, but there is another story there! We are now buying an electric oven!
I hope you don't have the same problems we have had.
Regards
Grant
P.S. When the 900gtf is working it is a great oven.
grant, November 2006