Furnace Wiring short (blown fuse in thermostat)

JimS

Member
We just had a service call on our four month old 2016 26LRSS as the furnace wouldn't start on a below-freezing morning. The symptom we saw was a blown fuse in the thermostat each time we tried to turn the furnace on. Our technician said there are two wires going from the thermostat to the furnace but only one is used. The other is live and was left just hanging above the furnace compartment. It was uncapped and fell down to contact the metal case causing a short. If that is standard practice Heartland needs to better secure live wires.

He was also concerned that the copper tubing where the propane connects to the furnace has too tight of a turn under the black pipe that runs above it. It looked crimped and could eventually leak. He said it should be replaced by a flexible gas line.
 

danemayer

Well-known member
We just had a service call on our four month old 2016 26LRSS as the furnace wouldn't start on a below-freezing morning. The symptom we saw was a blown fuse in the thermostat each time we tried to turn the furnace on. Our technician said there are two wires going from the thermostat to the furnace but only one is used. The other is live and was left just hanging above the furnace compartment. It was uncapped and fell down to contact the metal case causing a short. If that is standard practice Heartland needs to better secure live wires.

He was also concerned that the copper tubing where the propane connects to the furnace has too tight of a turn under the black pipe that runs above it. It looked crimped and could eventually leak. He said it should be replaced by a flexible gas line.

A loose wire might have been the cause of your failure, but I think both thermostat wires are normally connected. The Suburban wiring diagram shows one wire goes directly to the circuit board and the other goes to the limit switch and sail switch, then on to the circuit board. If you never used the furnace before, perhaps it was like that from the factory. But if it's worked before, it's likely that when the furnace was opened for service, a wire was pulled loose. Don't ask me how I know.

RVIA codes dictate what type of gas piping is used on RVs. Your tech may have a good idea, but the current setup complies with RVIA codes. Not sure if a flexible line would.

Glad you got it fixed.
 
Top