Carrier blowing cold air while heat pump is defrosting
#1
Member
Thread Starter
Carrier blowing cold air while heat pump is defrosting
I have two units in my new home. I noticed my upstairs this past weekend blowing extremely cold air during the outdoor unit defrost cycle. I never noticed this with my main floor unit before replacing the thermostat and it certainly does not do it now. What might cause this?
Thanks,
Mike
Thanks,
Mike
#2
Depending on where you are located..... you may not have two heat pump systems that have electric back up heaters. When in defrost mode.... without backup electric strips..... the air will be cold.
Defrost is the system running in standard A/C mode.
Defrost is the system running in standard A/C mode.
#3
Member
Thread Starter
It has backup heaters. I tested the emergency heat, it works. I noticed I'm missing a jumper between e and w2 not sure that matters.
Mike
Mike
#5
Member
Thread Starter
Vive TP-N-721. I only mentioned the jumper because my downstairs had the same thermostat and it had a jumper. You also helped me swap it with a Honeywell. By-the-way thanks again.
#6
Yes..... that will require a jumper between E and W2.
You have one set of electric coils serving both functions.
You have one set of electric coils serving both functions.
#7
Member
Thread Starter
Of course at closer look. The upstairs is wired differently. It has a wire at w2 and one at E. The downstairs only had a wire at w2 and then the jumper to E. I'll need to get in the attic and see how everything is wired at the unit.
#8
Yes.... that's what you need to do. Typically the W2 and E wires are combined at the air handler end. The thermostat does not control the electric heat in defrost. The defrost board in the outside condenser powers the W2 wire to bring on the electric coils.
You should see R, C, Y, W2, O ......... five wires going out to the condenser.
You could post a picture or two of the wiring...... How-to-insert-pictures
You should see R, C, Y, W2, O ......... five wires going out to the condenser.
You could post a picture or two of the wiring...... How-to-insert-pictures
#9
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Thread Starter
Outside unit checks out ok. Five wires just as you indicated. The main unit in the attic. I thought I found the problem. The w2 wire coming from the outside unit was not securely fasten within the wire nut. I fixed that closed the unit and now aux heat is running but it's running all the time instead as supplimental. I ran out of day light so tomorrow will be round two with photos.
#10
it's running all the time instead as supplemental.
That would indicate a defrost board problem.
HOWEVER....... if the room temperature is more than 3 degrees lower than the setpoint..... the thermostat will turn on the W2 line until the temperature rises closer to setpoint.
#11
Member
Thread Starter
Assuming the thermostat is working correctly. There is an indicator on the display that tells you auxiliary heat is on.
It looks like all is well. I think both were running because the heat was turned up as you mentioned. The remaining cycles were normal after the initial run.
I haven't caught a defrost mode yet. Probably because I no longer have that blast of cold air to signal me.
Thanks Mike
It looks like all is well. I think both were running because the heat was turned up as you mentioned. The remaining cycles were normal after the initial run.
I haven't caught a defrost mode yet. Probably because I no longer have that blast of cold air to signal me.
Thanks Mike