Condensing furnace will freeze.

thp_8

If you look into most furnace manufactures info. they also state that the units return air temp. should not fall below 55*F on most new models. This is to prevent condensate from starting before the recoup coil.

HT in Pa

Condensing furnace trap will freeze up.

I've installed a 92% efficient Ducane gas furnace in a camp in northeastern USA where the electric goes off sometimes for a week at a time! The owner wants to keep the thermostat set at 40 deg. F during the week when he's not there. He always winterizes the water lines, but the problem is the internal condensate trap will surely freeze up when the power goes off. There's a vacume hose attached to the trap that will not allow the furnace to operate again when power is regained, if the trap is froze up. I've thought about putting heat tape on the trap which would melt the ice when power comes back on, then allowing the furnace to operate again. I've also heard of an antifreeze drip system, but don't know if that would work. Also, will the PVC trap break when it freezes, complicating the problem? Anyone ever deal with this problem? I'd appreciate any suggestions. Thank you.

jim lockard

90 plus

I have found several 90 plus furnaces in both attics and crawls, frozen over the years.
If no one is going to be at camp and the water is shut off I would shut down the furnace and clear the trap of water. In occupied building I have built tents with insulation and opened the duct to blow a little warm air to keep furnaces from freezing. The easy way is to not use a condensing furnace in unheated space. Best Wishes J.Lockard