My Lennox G 20 furnace starts up well but the gas valve doesn''t open. A repairman said there was voltage to the gas valve but insufficient to open it. He suggested the ignition module. As both of these parts are expensive and only one is faulty, I am wondering if this diagnosis sounds plausible. Would an ignition module sent electricity to the gas valve in an insuffient amount? It is a low voltage gas valve (24v) Isn't it just as likely something is blown or jammed in the gas valve?

Ideas?

BW

Would an ignition module sent electricity to the gas valve in an insuffient amount

Yes it is possible.

It is a low voltage gas valve (24v) Isn't it just as likely something is blown or jammed in the gas valve?

Yes it is operated by 24 volts. It is possible the gas valve is defective.

Both are possible but I feel unlikely that both items would be defective at the same time. Looks like someone wants to sell a new furnace or rack you with a big repair bill. Call another company and get there opinion if you do not like the opinion of the first.