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Replacing old thermostat with Wifi stat- Issues with heat pump wiring/no Y wire!

Replacing old thermostat with Wifi stat- Issues with heat pump wiring/no Y wire!

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Old 07-16-15, 12:38 AM
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Exclamation Replacing old thermostat with Wifi stat- Issues with heat pump wiring/no Y wire!

I am currently replacing my thermostat with a newer (Honeywell wifi) thermostat model RET97E5D. I am having 2 issues as of now.

First is there is no "C" wire. Now I did add a C wire that works (and powers on) the new thermostat. In order to achieve this I had to splice in a new wire with the neutral wire coming from the compressor outside. The wire coming from outside has 2 conductors in it, one that is spliced into the BLUE (O/B) wire on my thermostat, and the other that is spliced into a brown wire on the air handler. Splicing a new wire into the brown wire side and connecting that to C gave the thermostat power. I am pretty sure I did this right, but please tell me if I am wrong.

My main issue is the OLD thermostat does NOT have a Y or yellow wire. It only has a Blue wire connected to O/B, a Red to R, White to W, and Green to G. At first I just connected the wires to the new thermostat in the same manner with a few exceptions. I connected the additional "C" wire; and the old "W" wire no longer has a "W" terminal at the thermostat. It only has O/B and AUX/E. I connected the "W" wire to the AUX terminal since I would assume it would be connected as the auxiliary heat source.

With the thermostat wired this way the fan comes on and blows air, but the compressor will never come on for either cooling or heating. I changed and tried every function setting on the thermostat changing it from heat pump, to conventional, to heat pump WITH auxiliary heat, O wire, B wire, and every combination in-between. I even tried switching the W and O/B wires thinking they were wired incorrectly, moving the O/B (blue) wire to the Y terminal, moving the W wire to the Y terminal, and it will still not turn on the compressor.

The bad thing is the air handler must be older and does not have any terminals to connect wires (see picture) and everything is spliced into a different wire that plugs into a control board that has the label R,G,T,C,C,C. I imagine these coordinate with the same wires as the newer terminal connections and (so far) have proven so.

I attached pictures of the inside of the air handler, the control board, and the OLD thermostat. Please help!





 
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Old 07-16-15, 10:50 AM
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Connect blue to Y on the new stat.
It is either an optical allusion because of the angle or the old stat was incorrectly wired.



You do not have a heat pump.
A heat pump requires O, C, Y, W, and R to the outdoor unit.
2 conductors indicates a conventional AC condenser.
 
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Old 07-16-15, 11:23 AM
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Thanks for the reply! I will try that as soon as I get back home.

The model number I was able to pull off the compressor outside is H2A348GKA100. My searches yield few results, nothing saying that it is definitely a heat pump.

Another note: after my failed attempts of connecting the new thermostat last night I put the old thermostat back on so I have A/C while sleeping and I wired it so that the blue wire is definitely in the O/B slot and the AC works fine this way. Will a conventional unit work if the "Y" wire is installed in the O/B slot?

Thanks!
 
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Old 07-16-15, 08:21 PM
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I looked up your model number for your ICP unit and it is only an air conditioner.... not a heat pump.

Usually the O/B slot has 24v on it when the stat is turned to A/C. That port is used to supply power to the reversing valve on a heat pump.

Like Houston posted..... you should have the blue condenser wire on the Y terminal.
 
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Old 07-16-15, 10:07 PM
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Thanks a bunch for the responses! That fixed the problem. Whomever wired it before I moved in just did a very poor job.
 
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