[Austin1983]

Today our electric heater began blowing cold air during one of the cycles. It has been around 30* all day outside and we have kept the heater at 70*. The heater had been running about 7 min. when I noticed cold air blowing so I switched to emergency heat and the air felt slightly warmer but still very cool. I turned it back to the normal heat setting and the furnace turned off, and the thermostat showed "wait" and it was off for a minute or so and it came back on blowing hot air. We are fairly new in this home so I am very unfamiliar with electric heaters and heat pumps. I had the heater checked recently and everything was fine. Im just concerned if the blower would have kept blowing cold air until someone jacked with the thermostat, and i know a tech would be unable to diagnose anything if it is working properly while he is here. It has been working normally since then. Any help would be greatly appreciated.

 

[Marty S.]

Probably went into defrost mode. When that happens the heat pump is actually running in air conditioning,taking some of the indoor heat and melting the frost on the outdoor coils. Nothing to worry about

 

[Missouri Bound]

:yes:Most heat pumps go into a timed defrost cycle when the temperature gets below a pre-set point. What is supposed to happen is that the aux heat kicks in to overcome the cooling cycle. It may not be a bad idea to have that function checked before "real winter" hits. Where are you located?

 

[Austin1983]

Thanks for the help guys, I live in north Texas. Average lows 33 this time of year. Been a cold day here today with snow.

 

[Missouri Bound]

You mentioned that you switched on the emergency heat. You shouldn't need to do that. Next time this happens look at your t-stat...the emergency heat light may be flashing. If you can also look outside at the compressor, the fan should have stopped but the compressor would still be running. If the humidity is high enough you may see a cloud or vapor escaping from the outside unit...perfectly normal.

 

[Austin1983]

It did it again this morning and it was in defrost mode because the outside fan was not on while the heat pump was running. It only blew cold air for a few minutes before switching to hot air. Is it supposed to have an aux. heat strip that will somewhat heat the air during defrost? The air felt cold to me, but it is hard to tell since any air below skin temp feels cool. It was unusually cold (20*) with snow this morning so we shouldn't have to deal with defrost often. We have a home warranty with this home, but I don't want to pay $75 again for them to tell me it's working correctly.

 

[beenthere]

You may not have enough aux heat to warm the air while its in defrost. A 3 ton heat pump with only 5 KW of aux will blow out cold air in defrost.

 

[Missouri Bound]

If you can posts some specs, or a picture of the heat pump name plate. If it came from the factory with heat strips it may be listed on the plate. It's foolish to have aux heat on a heat pump which is not adequate to overcome the defrost cycle, but unfortunately it is done too often. You may be able to rectify this if need be but it may require a higher amp circuit to the air handler. If you know the specs we may be able to advise and help a bit.

 

[Austin1983]

If you can posts some specs, or a picture of the heat pump name plate. If it came from the factory with heat strips it may be listed on the plate. It's foolish to have aux heat on a heat pump which is not adequate to overcome the defrost cycle, but unfortunately it is done too often. You may be able to rectify this if need be but it may require a higher amp circuit to the air handler. If you know the specs we may be able to advise and help a bit.

I have to work tomorrow so I'll take a photo or post the information on the heat pump on Friday morning. I know the outside unit is a Trane 2TWR4048A 1000AA (date: 9/2005). It defrosted again this evening and it ran for about 4 minutes before the heat kicked on. Thanks a bunch for offering to help.

 

[Missouri Bound]

It sounds like it's working correctly, just may not be configured for optimum performance. Does that defrost cycle last more than 4 minutes, or jut the cool air blowing for that time?

 

[Austin1983]

It was blowing cold air out for 4 minutes. After I felt warm air in the vent I went outside and the fan on the outside unit was blowing so I assume it was done defrosting. We typically don't have snow or these low temps so its not a huge deal.