Got E: 140 heat exchanger overheating. The propane company came out and replaced the internal circulator 2 weeks ago. Last night same error. they replaced it again but it still didn't work and they said I needed an external circulator as well. They left for the shop and now they're telling me the whole thing is piped wrong (they didn't install it but they inspected the install). I don't know what it'll cost but it's supposed to be 14 degrees tonight so I told them to get the heat going and give me a price on repiping but I think they're selling a load of nonsense. It has already cost me $1400+ for the nonworking "new" circulator so I'm hesitant to keep throwing money at this based solely on their say. I no less than nothing about these systems, I need some help please.