How long should it take to bleed a propane furnace after the gas has been turned off? We have a plumber here now. He has been here for 2 hours and says it is going to take another 2 hours or so to bleed the propane gas line to our furnace. Seems like a long time and a LOT of money...

Insane. My line is 200' feet from the house and it took the delivery guy 10 minutes, including getting the covers off the furnace. (When I ran out of propane once)
Why didn't you have the propane company do this? Ask the 'plumber' for his license number and check it online.
You had the tank filled, right?

Am I missing something here, all you real plumbers?

Last time I did mine, I added another tank, 80 ft., it took less than 5 minutes. How far is the tank and how many regulators?

He is bleeding your wallet not your furnace. How is he bleeding the line, where are his hands?

I agree, 5 or 10 minutes, beyond that he either does not know what he is doing (dangerous) or he is cheating you.