HI,
I have a furnace that won't stay in. The blower keeps blowing, but the heat cuts out because the flames get shut off every two minutes or so.

Over the summer, we remodeled and streamlined the duct work. We eliminated lots of big runs that absorbed all the heat. Now, though, I think we do not have enough. We have one small duct run blowing directly into an open auditorium (its for a church. We don't keep the heat on constantly, but instead need to be able to heat the room quickly when the building is used. Could the problem be from this--not enough returns or vents?

Secondly, I'm not sure if the gas is open all the way. We shut it off this summer, and there is an old valve. The flow through the lines is weak. Someone said that is how gas lines are supposed to be. Someone else said it should have more pressure. Would that cause it to keep turning off the heat?

The unit did survive a flood. Don't know if that could have blown something either. Thanks for your help