Heat Pumps and Electric Heating - Tempering heat pump defrost cycle....

I know that electric strips can temper air temps during a heat pump defrost cycle. Can this also be done with a natural gas furnace? I thought it was not a good idea to blast furnace heated air onto an operating heat pump coil?

Huh my dual fuel kit for my heat pump and gas furnace worked exactly that way when it was installed. When it worked it was great - no cold air blowing into the house.

However....The problem I ran into was that if I had a short defrost cycle the furnace would not have enough time to fire up because of the delays starting up the power vent and such before the defrost cycle ended and the heat pump came back on again canceling the heat call to the furnace. This confused the logic board in the furnace and caused it to lock out the gas heat permanently until it was manually reset.

I suppose I could have added a time delay relay or something, but it was easier just to pull off the wire for that feature.

-doug

The discussion here might help

Dual Fuel HP Defrost Question (Link removed)

not sure I would send any innocent DIYer's to the xxx site without the proper warnings. Listen to me people!!! there are some real mean spirited people (flamers) over there that really do not like DIY. The site is geared towards professional members.

I know that electric strips can temper air temps during a heat pump defrost cycle. Can this also be done with a natural gas furnace? I thought it was not a good idea to blast furnace heated air onto an operating heat pump coil?

Yes, it can be done with lot of the newer gas furnace.. I would not advise it on oil system since the air is much hotter.. But then on some of the older system. it takes a while to get the heavy heat exchanger to get up to temp.