# Thermostat changing from Heat pump to Elec



## CRE (Jan 2, 2010)

We had a heat pump system when we first moved to our house it failed and since I had a friend in the HVAC supply business, he gave me a good deal on teh outside electric unit and we installed it. This was about 10 years ago. We live in Florida, so the heat strips that were in the air handler as part of the emergency heat has provided for our heating needs. The current set-up works fine for cooling as everything is automated. However, in heat mode, the thermostat will not call on the air handler. We have just been turning ON the fan and setting the thermosat. The fan runs continuous and the heat strips cycle on and off from the thermostat. I have purchased a new digital thermostat and wanted to set it all right. The air handler is a Trane. the terminals are as follows:
W1 White
W2 Yellow
W3 Black
B Blue
O Orange
R Red
Y1 no wire
Y2 no wire
T Tan
G Green
I have a feeling some of this needs to be rewired to properly operate as an electric system, but am unsure exactly what to do. Any help is greatly appreciated.


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## Stedman (Jun 4, 2006)

with Y1 and Y2 not having anything hooked to them you're never going to call for your air conditioner to come on.. 

chances are if you changed the system from a heat pump to electric strip heat only you'll need a new thermostat unless the stat you have has the ability to operate both.

What i really need is the manufacturer and model number of the thermostat, as well as the wiring setup on the air handler. Also if you can provide decent quality pictures of the air handler with the electrical covers off. *Taking the covers off without turning the breaker off to the unit is dangerous because there is dangerous voltage exposed inside*


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## Stedman (Jun 4, 2006)

a quick fix would be for you to take the green wire on the thermostat and place it under the W1 terminal with the white wire. It will render your Fan Auto/On switch useless but it should make your strips and fan operate in unison until we get the wiring straightened out


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## CRE (Jan 2, 2010)

The wiring connections I noted are on the air handler and the AC works fine. I have tried to attached a picture of that terminal, but the attachement feature does not seem to be working. The new thermostat I purchased is a Hunter Model 44155C.


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## CRE (Jan 2, 2010)

Picture is attached.

Thanks


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## Stedman (Jun 4, 2006)

Inside of the new thermostat you should have a couple of "dipswitches" one of them should be labled "STD - HP" make sure that switch is in the "STD" position. The other switch should be labeled "HG - HE". Hunter claims that the factory set position for this switch is HG, if that's the case then switch it over to HE and make sure your green wire is hooked to the G terminal of the thermostat. If that solves your problem we can stop there but if everything still isn't working correctly we can go further into the process of re-wiring everything to work as a single stage cool/electric heat system.
I'm really hoping that this solves your problem because walking someone through an entire re-wire via message board sounds like quite a task.


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## CRE (Jan 2, 2010)

Thanks for the info and reply. I am working some late hours this week and will not be able to get to it until the weekend. I'm still not sure where to hook the other wires too though. I noted above the wires coming from the air handler, and the stat has a place for the following:
G
RC
RH
Y/O
W/B
Y1

In the new and old stat, the RH and RC ( I assume Heat and Cool) are jumpered together and from what I have read elsewhere, this should be correct. The current stat has yellow connected to Y1, green hooked to G Red hooked to either RH or RC, and I believe the white was connected to W, but without removing it again, not sure on that one. The Blue, Orange, Black and Tan are not connected to anything on the stat end. Thanks again for the help.


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## Stedman (Jun 4, 2006)

That sounds right.
RH/RC is 24v power and they should be jumped together for a single transformer system
Y is the compressor contactor
G is the indoor fan relay
W is the heat relay/contactor

Blue, Orange, Black, and Tan aren't going to be used on the new stat for anything so clip them off and tape up the ends separately so they cant touch anything.


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## DonaldG (Aug 23, 2007)

Hello CRE

I know nothing of the wiring of American heat pumps, so I cannot help on that score.

However, looking at the photograph that you posted, I note a couple of points that look a bit 'iffy'.

First of all, it is essential that you read the TSF Warning here.










The wiring does look rather old, so be very careful when moving any of the wires. The insulation could be brittle and break away causing a danger of electrical shock and or short circuit. The short circuit could, in worst case, cause a fire.

The two wires marked A & B are dangerous because of the excessive length of exposed copper wire before they enter the screw clamp. If moved, they could short out against the terminal on the right.

The 'pig-tails' marked C appear to be very close to the terminals on their left. They should be checked and attended to if necessary.

Regards
Donald


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## speedster123 (Oct 18, 2006)

The casing on that low voltage coming into the unit appears to be asbestos.


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## Stedman (Jun 4, 2006)

The weekend has come and gone CRE, how'd this work out for you?


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