How to change TStat wiring from conv to heat pump to utilize the AUX/EM heat


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Old 12-27-12, 06:30 AM
J
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Question How to change TStat wiring from conv to heat pump to utilize the AUX/EM heat

My setup includes a Lennox Heat Pump with with Aux/EM heat. I have a single unit in a 2-story house, so I have 2 seperate Honeywell TH6220D thermostats with a Honeywell HZ322 TrueZONE.

Last night I noticed that my system was taking more than 2 hours to increase 2 degrees when the outside temp was about 20 degrees. The thermostat was set on 68 while we are at work and then to 73 at 5PM for when we get home and it just wasnt getting to 73 in the house. I ended up calling the installer and he explained that the thermostat should automatically kick on the aux heat (or stage 2 as he called it) if it was wired to do so. After checking, we realized the thermostat was wired conventional as shown below:

Red wire to R (and a jumper to Rc)
Yellow wire to Y
Brown wire to C
White wire to W
Green wire to G
Orange wire not used
Blue wire not used
Black wire not used (I think there is a black wire, but I couldnt get it out of the wall yet)

We then checked the TrueZONE and it was programmed for the aux/em heat to be activated by the thermostats. Of course the aux/em heat never came on because the thermostats were not wired to do so. So, just to get the aux heat to come on, we programmed the TrueZONE to come using the stage 2 timer set to 20 minutes. This worked and got my house warmed up nicely in no time.

I say all that just to ask how I need to wire the thermostat for the heat pump so that I can utilize full capabilities of my thermostat so that the thermostat will automatically kick on the aux heat when needed and it will give me the option to use the Em heat at the thermostat down stairs instead of running up stairs to the unit in the closet to turn it on. Another function I would like to use is the "Auto" System setting that changes between Heat and Cool automatically. The conventional wiring setup does not allow me to do this.

I believe this can be changed from conventional wiring to heat pump with the wiring that is already in the house (spare orange, blue, and possibly black). Is this true? How would I connect it? Also this may sound like a stupid question, but do I need a different terminal block on the thermostat to switch between conventional and heat pump or ar they one in the same? I just noticed that the conventional is at the top which is where the wires come into, but the heat pump labels are at the bottom and there are no openings at the bottom of the terminal block.

Here is my thoughts on the wiring, please correct me if I'm wrong.

TrueZone Wire Color TSTAT
R------------RED----------R (jumper to Rc)
Y1----------YELLOW-------Y
C-----------BROWN--------C
O/B---------WHITE--------O/B
G-----------GREEN--------G
W2---------ORANGE-------AUX
W1/E--------BLUE---------E
L------------BLACK--------L

Thanks in advance for your help!

Jon
 
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Old 12-27-12, 06:57 AM
J
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Also, for the thermostat installer setup, do I change it as follows:

System Type: 5 2heat/1cool heat pump
Changeover valve: 0 O/B terminal energized in cooling
Fan Control: 1 Electric Furnace
Heat Cycle Rate: 9 For electric furnaces
Second stage Heat cycle rate: 9 for electric furnaces
Emergency Heat cycle rate: 9 For electric emergency heat
Compressor cycle rate: 3 Recommended
Second stage compressor cycle rate: 3 Recommended for most compressors
System setting adjustment: 1 Auto changover (Heat/Cool/Auto/Off)
 
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Old 12-27-12, 07:24 PM
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Your wiring will work but I recommend 3 cycles per hour for the second stage and emergency heat. (Funny color code though)



do I need a different terminal block on the thermostat to switch between conventional and heat pump or are they one in the same?
It's the same terminals just different functions on the stat.

 
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Old 12-28-12, 12:33 PM
J
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Thanks for the help! Regarding the cycle rates? Would a value of 3 for the 2nd stage and em heat not increase my electric bill unneccessarily? Please don't think I'm second guessing you, I really just don't have a clue as to what is recommended and the effects it may have on efficiency.

Jon
 
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Old 12-28-12, 12:39 PM
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Thanks for the help! Regarding the cycle rates? Would a value of 3 for the 2nd stage and em heat not increase my electric bill unneccessarily? Please don't think I'm second guessing you, I really just don't have a clue as to what is recommended and the effects it may have on efficiency.

Jon
 
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Old 12-29-12, 11:06 AM
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It will likely NOT increase your electric bill, but it will definitely run better when set to 3 instead of 9. You will have more even heat and the strips wont cycle as often.
 
 

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