Which heat is run during heatpump defrost ?

[adamk]

I've got the TH8320 honeywell tstat.

Which heat is run, aux or emergency when the heat pump (Amana ASZ140361) begins its defrost cycle ?

The tstat is setup as 3heat/2cool (though there isn't 2 cooling stages.)

Thx.

Adam

[tecman]

In nearly all systems, Aux heat and emergency heat are the same thing. In some bigger systems, the Aux heat may be staged, but again the same elements are used.

paul

[Mikeylikesit]

and.....

the defrost call comes from the control board, not the t-stat.

[adamk]

I see;

So it depends on how the installer hooked it up.

Thanks.

Adam

[Sonicview]

usually the aux heat comes on while the HP is in defrost. when there is a call for defrost the HP automatically locks itself out, at that point the HP will put out a W2 signal... enabling aux heat..

[Airmechanical]

when there is a call for defrost the HP automatically locks itself out

i think you need to re-evaluate that comment!



.

[Sonicview]

i think you need to re-evaluate that comment!



.

ok... technically speaking..it doesnt really "lockout". Defrost mode is identical to cooling mode except that the outdoor fan motor stops and auxilary heat is turned on to continue heating the house.
Defrost is engaged by the defrost control board and utilizes a temp/timer control which includes a field adjustable time period between defrost cycles of 30 60 or 90 minutes...
So , airmechanical is correct...it does continue to run but, it is just not heating the house, it is defrosting...but essentially the HP is "locked-out" from providing heat,... so, it enables auxilary heat until it has completed it's defrost cycle.

[beenthere]

Since HPs and aux heat can be locked out.

You shouldn't use term locked out to describe HP defrost operation.
It will just confuse to many people.

[Airmechanical]

Defrost mode is identical to cooling mode except that the outdoor fan motor stops and auxilary heat is turned on to continue heating the house.

you left out one part;

what about the reversing valve!



.

[Sonicview]

you left out one part;

what about the reversing valve!



.

[lentz]

Surely we all know what the reversing valve does during the defrost cycle.