jrw1621
jrw1621 SuperDork
12/1/11 2:11 p.m.

I bought this house in July. It is heated with all electric and has two heat pumps (one for the living area and one for the bed areas.) These are large units that sit outside like a AC unit. In the crawl space there are blowers, filters and traditional forced air duct work.
The temps are dipping for the first time below freezing.
Starting yesterday, I see on the thermostat a red flashing light in what I think means Emergency Heat.

This red light flashes (which typically means danger.) The house temp is consistent and comfortable.
If I move the switch off "Norm" the light stays steady.

My question to those more knowledgeable about heat pumps is do I have a problem or is this "normal"?
I have not seen this same behavior from the bed area thermostat.

What does Aux. Heat mean? I have seen that light come on in the bedroom area.

RossD
RossD SuperDork
12/1/11 2:20 p.m.

Many times the heat pumps will also have electric coils in for extra heat. Now whether the electric coils in the system is considered auxillary or the emergency... I'm not sure.

found this: http://www.trane.com/webcache/un/unitary%20accessories%20(acc)/service/ther-in-53_04011998.pdf

The other form of heat could be the perimeter electric baseboard.

Dr. Hess
Dr. Hess SuperDork
12/1/11 2:23 p.m.

That's how mine work. The electric heat, auxiliary or emergency, whatever you want to call them, kick in when the outside temp drops too low or the difference between inside ambient and the thermostat setting is too much.

Powar
Powar Dork
12/1/11 2:31 p.m.

^ What he said, except I don't think mine does it automatically. If I leave it on regular heat, the heat stays on much more(working harder to keep up, I suppose), but the temperature is stays consistent regardless.

I did some reading on my system and it looks like the E-Heat uses about twice the power. I've only used it a couple of times to see what it would do.

failboat
failboat HalfDork
12/1/11 2:54 p.m.

mine works exactly how you guys are describing.

The system in my house is fairly new, and has one of those fancy electronic programmable thermostats, I can set the temperature difference (between ambient and thermostat setting) at which the emergency heat will kick on to help warm the house.

but here read this http://www.trane.com/webcache/un/unitary%20accessories%20(acc)/service/ther-in-53_04011998.pdf

maybe the flashing light indicates there is a problem with your auxilary electric assist on that particular heat pump?

jrw1621
jrw1621 SuperDork
12/1/11 3:44 p.m.

Thanks for the replies but two of you have placed links to Trane but neither of them will take me to a specific page, rather when I click on them I get a Trane webpage saying "page not found".
What are you searching to find that link? Maybe I too can search it and find.

To Ross: I do not have perimeter heating, just forced air.

bludroptop
bludroptop SuperDork
12/1/11 3:50 p.m.

I had a HVAC service tech at my house today. Mrs. BDT said she was cold, and the heat wasn't working upstairs. It cost $89 for him to tell me that everything is working properly. He said that most systems will cycle the EM heat on and off any time outside temp drops below 40 degrees F.

He also said that it is more efficient for the heat pump to maintain a constant temperature rather than use the programmable thermostat to lower the temperature during sleeping time or when the house is unoccupied.

jrw1621
jrw1621 SuperDork
12/1/11 3:54 p.m.

Thanks BluDrop. Do I owe you half of $89 for that wisdom?

failboat
failboat HalfDork
12/1/11 4:48 p.m.

In reply to jrw1621:

I searched trane weathertron thermostat on Bing and found the link. It's an install guide for yours.

Curmudgeon
Curmudgeon SuperDork
12/1/11 6:14 p.m.
bludroptop wrote: He also said that it is more efficient for the heat pump to maintain a constant temperature rather than use the programmable thermostat to lower the temperature during sleeping time or when the house is unoccupied.

He's right. There are SO many people who just don't understand this concept. To the OP: I had a thermostat exactly like yours and it too would flash when the emergency heat strips (think stove elements in the air handler) kicked on.

dj06482
dj06482 GRM+ Memberand HalfDork
12/1/11 7:28 p.m.

What everyone else has said. We have a relatively new and more efficient heat pump, so the cut off is closer to 20 degrees F before the heat pump can't keep up. Just a warning that the emergency heat is not the most efficient, so you'll likely suffer through high electric bills while that's running.

jhaas
jhaas Reader
12/1/11 7:59 p.m.

the aux or emergency heat is just a HUGE electric resistence heating coil just above the blower motor. they come on automaticly to warm the air while the heatpump is getting going. it will also come on to assist the heatpump if it cant keep up withdemand, or its to cold outside (around 30 deg) you can however manualy switch to emergency heat if the heatpump fails.

they draw between 5kvw and 20kvw, so think of it as a HUGE hairdryer = very expensive.

RossD
RossD SuperDork
12/1/11 8:43 p.m.

If you're not getting enough heat you could do a DIY solar collect to put heat into the forced air system. Or use domestic hot water in a DIY hot water coil.

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