Honeywell Programmable TH8320U Thermostat Connection and set up

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  #1  
Old 09-26-10, 04:50 AM
J
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Honeywell Programmable TH8320U Thermostat Connection and set up

My HVAC installer (brother-in-law - supposed to be a pro that lives 3 hours away and too far to come back and troubleshoot this for me) hooked up my programable thermostat but it seems there is a problem. It works fine when cooling but when the thermostat is in heat mode it will make set-point but will immediately switch to cool. Make setpoint again and continue to cycle back and forth. I kind of figure this will wear out my heat pump and is not too good for my utility bill either. I am using the Honeywell TH8320U programmable thermostat with a heat pump system using gas for emergency heat on the air handler. I guess the first step is to make sure the connections are right so here is how it was connected:

Thermostat ----------- Air Handler --------Heat Pump
R----------------------R-------------------R
Rc--jumpered to R
Y----------------------Y-------------------Y
C----------------------C-------------------C
G----------------------G
E----------------------W
AUX----------------------------------------B
Thermostat - O/B--not used
Thermostat - Y2--not used
Thermostat - L--not used
Heat Pump - D -- not used

Photo of thermostat connections:


Photos of air handler connections:




Photos of Heat pump control bd and connections:




Any help is appreciated.

TIA
 
  #2  
Old 09-26-10, 11:01 AM
Houston204's Avatar
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You need to move the blue wire at your stat to O/B, and move the purple D wire at the outdoor unit to white.

Thermostat ----------- Air Handler --------Heat Pump
R----------------------R-------------------R
Rc--jumpered to R
Y----------------------Y-------------------Y
C----------------------C-------------------C
G----------------------G
Aux & E--------------W-------------------D
O/B----------------------------------------B

Thermostat - Y2--not used
Thermostat - L--not used

You must also configure your stat for heatpump with backup heat (option 170 = 7)
configure option 190 to 1 (energize the O/B terminal for heat)
It appears that you are using the outdoor temperature sensor wired to S1 and S2.
If so then 200 = 1
210 = 0.

 

Last edited by Houston204; 09-26-10 at 11:50 AM.
  #3  
Old 09-26-10, 04:47 PM
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Houston,

Thank you. Problem solved. Sorry for posting this twice. I just found your first answer. First time on the forum and learning how to navigate it.

I am going to install and identical thermostat one on my package unit next week. It has a standard heat pump mercury thermostat on it. I noticed that the control wire (Bk) for the emergency heat was not connected at the unit. Opened the panel for the first time when I ran a new thermostat cable. It has been this way for years and we got by fine. Well, almost. Emergency heat light would come on but it never seemed to make any difference. Anyway, wanted to know if there was anything I might need to check before connecting it. BTW, it is an older R22 system. RUUD Mod: UQKA-A030JK 010. MFG date 08/01. I know the new 410A is more efficient but it still runs like a champ and I can't bring my self to part with a working piece of equipment. I am hoping to get 10 more years.

Main question is that since the Coding is slightly different on the connections, how do I transfer the connections from this thermostat to the new Honeywell?

Current connections:

B----Blue
L----BlacK - disconnected at unit. I assume this is emergency heat.
W2--White
X----Brown
G----Green
R----Red
Y----Yellow
O----Orange
E----not connected

Thermostat connection photo:


One more thing. I would like to hook up the 24v to the thermostat to get the backlight to work full time. Is there a 24 volt connection available at the air handler on the previous unit or on the RUUD package unit without having to add a transformer?

Once again, Thank you for your help.
 
  #4  
Old 09-26-10, 06:33 PM
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Both stats will already have common. just set option 280 to 1.

O/B----Blue
Aux & E--White
C----Brown
G----Green
R & Rc----Red
Y----Yellow
Orange-- not used
Black---not used

170 = 7
190 = 1
200 = 0
280 = 1
 
 

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