Update: 8Pm- I fixed it! Took it all apart... Used air... Blew out thermo with air too...reseated connectors on and on ... Still would not light... Kept getting the,3 red blinking lights... Was about to give up when I read online about a guy that had the exact same issues...,it tuned out to be his propain tank (even tho just like me the stove works fine) so I went to my tanks and shut off the tank.... Then SLOWLY opened the valve... Tried the furnace and it started right up. Technically I have no idea what was going on but I can tell you the furnace has not worked in 3 years. Could it be some sort of air bubble, or blockage in the propain lines? Don't know but it's working now. Thanks for all the input. CWT
The furnace is a real gas hog......stove not so much.
When you quickly open the valve on propane cylinder there is a ball bearing check valve inside the pigtail hose nut. It limits the amount of flow that can go thru pigtail....it should fully open when pressure on both sides equalize. Sometimes they don't and closing propane valve then slowly opening it can allow that ball bearing to move fully open. (They are excess flow valves designed to close if there is a sudden increase in flow)
How old are the pigtails on your cylinders? The 'check valve' may be sticking due to moisture/oily residue from propane.
