Heat pump thermostat install


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Old 01-03-17, 08:22 AM
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Heat pump thermostat install

Hi. I've changed out thermostats before, but never one for a heat pump. Currently there is a White Rogers hooked up with the following wires.
W2-white
E-black
O/B-orange
R-red
L-empty
G-green
C-blue
Y-yellow

I purchased an Aprilaire 8465 for heat pumps but there isn't a spot for E or W2. I'm assuming the W2 will hook to the W. Where would I hook the E (black) wire? The Aprilaire has the following.
RC and R (jumpered)
W
Y
G
C
S1-outdoor temp sensor
S2-outdoor temp sensor
O/B
L

Any help would be greatly appreciated, so I don't have to spend $200-300 on a professional install. Thank you.
 
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Old 01-03-17, 08:46 AM
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Welcome to the forums.

This should be what you need to follow.

W2----> white------> W
E------> black-------> tape off
O/B---> orange-----> O/B
R------> red---------> R and Rc (use jumper)
L------> empty
G-----> green-------> G
C-----> blue--------> C
Y-----> yellow------> Y
 
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Old 01-03-17, 09:29 AM
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Will you be using the outdoor temperature sensor to control the function of the auxiliary heat?
 
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Old 01-03-17, 06:14 PM
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Thanks PJmax.

I do not plan on using the sensor. Is this something I should consider?
 
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Old 01-03-17, 06:18 PM
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If you don't plan on using it, then you'll want to disable the program and have the thermostat hold a constant temperature. To minimize the use of electric heat. Basic programmable thermostats can increase your energy use if used with a heat pump with electric backup.
 
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Old 01-04-17, 05:21 AM
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Thanks for the help roughneck.

I can get the temp sensor and install it. Sounds like that would be the correct thing to do? There is a cold air return vent above the thermostat about 3 feet or i can drop it down into the basement and run it over to a vent. I could possibly drill through the wall in the basement and attach it outside by the unit. Thoughts?

Thank you guys again for your help on this issue.
 
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Old 01-04-17, 06:36 AM
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Can that thermostat lock out the electric heat based on outdoor temp? I'm not familiar with its operation
 
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Old 01-04-17, 09:11 AM
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This is what the installation book says under the outdoor temperature sensor installation.

"When the outdoor temperature is less than the low balance point, the heart pump will be locked out and only auxiliary heating will be used. "

"When the outdoor temperature is higher than the high balance point, the auxiliary heating will be locked out and only the heart pump will be used to provide heating."
 
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Old 01-04-17, 10:57 AM
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That sounds like a fossil fuel thermostat. Even at very cold outdoor temperature, such as 10-15*, I'd still want the heat pump operating to supplement the electric heat. But I'd want the electric heat completely locked out above an outdoor temperature above 40-45*.
Personally, I don't care for programmable thermostats on air source heat pumps with electric backup. The units tend to be very efficient maintaining a consistent indoor temperature
 
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Old 01-04-17, 11:06 AM
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Ok thanks for the help. I really do appreciate it. I've never delt with a heat pump. Maybe I should just have someone come check it out and service/ explain some things to me about it.

I'm thinking that maybe I should go with the rule...if it ain't broke don't fix it. Return the new thermostat and work on repairing/remodeling something else.
 
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Old 01-04-17, 03:42 PM
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Think of it this way. Providing the heat pump is running properly, its most efficient when the electric heat is off.
 
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Old 01-04-17, 04:03 PM
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What most people don't know or realize is that with a thermostat running a heat pump..... the electric reheats will come on when the room temperature is three or more degrees below the set point. The system thinks the heat pump is struggling.

This is one of the primary reasons why a setback thermostat is not recommended.
 
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Old 01-04-17, 04:52 PM
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Thank you both for your help and information. I learned something new and I think I'll do more research on heat pumps to educate myself further. I'll stick to what i know for now...woodworking. I hope you both have a great new year. Take care.
 
 

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