Hello, my name is Tommy. I have recently obtained a 1978 Sunline 18' towable trailer. The problem I am having is with my furnace. If I use the trailer's LP tanks the furnace will not work, but if I connect a rubber hose to the furnace and then to a LP tank the furnace works. All of the other LP appliances in the trailer work fine with the trailer's tanks (stove, fridge, hot water heater). I am very new to RVing and I am boggled by this. If I disconnect the trailer's line from the furnace while the propane is on I can here the gas so I know it isnt a kinked line. Can it be a bad regulator on my tanks? What should my LP pressure be?? Someone please help!! The winter is coming and I'm excited to go camping.