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View Full Version : How to chose and wire new thermostat?


bj236
Nov 2, 2012, 07:54 PM
Hi I would like to replace my old manual thermostat with a new Honeywell programmable digital touch screen thermostat. I have tried to do some research on my own and from what I've read it is best to get a thermostat in which you cn program the deadband to adjust the number of cycles per hour. I also heard it is good to program a minimum compressor "off time" before it allows to restart. Which would allow the compressor to bleed off the pressure remaining in the lines and allow it to start without any load. I am just quoting things I've read, this is my first time replacing a thermostat but I believe I am fully capable of doing it. Just need some assistance in determining the correct thermostat to purchase and where to connect the wires to the new thermostat. Someone had mentioned the Honeywell TH8321 or TH8320 thermostats? Not sure if these are the ones I'm looking for?

My old thermostat is a Lennox 67K4801 / 3AAT89B38G1

Old Slots = Color of wire

O = Orange wire
G = Green wire
Y1 = Yellow wire
R = Red wire
L = Tan/Brown wire
T = Blue wire
C = Black wire
W1 = White wire

My thermostat also has a light that has never come on but does say Emergency Heat.

I believe to the best of my ability I have a Heat pump with Emergency Heat (1 Cool/2Heat Stages) Not positive

Any help or advice would be greatly appreciated and I thank you for your time and consideration in this matter.

T-Top
Nov 2, 2012, 09:22 PM
It looks like you have a single stage heat pump system you may not have to use the L or T circuit with the new thermostat. You will need a heat pump thermostat for one stage cooling two stage heat. Just about all your digital thermostats will come set up for anti short cycle and will be set at 4 cycles per hour. The droop will be set when you configure it for gas heat or heat pump.

bj236
Nov 4, 2012, 06:22 PM
Thank you very much for your response! While I was looking up Honeywell thermostats they have something called precise comfort control which keep the comfort within +/- 1 degrees and had heard people complaining about it cycling their compressors, I mean a lot of people had good things to say but like always they're were those certain few people that had negative reviews, I just don't want to buy something that ends up costing me more energy than my old analog thermostat I am assuming if it cycled a lot it would use more energy and doing any extra work for my compressor shortening its life span, Would you recommend any specific thermostats or? Should I just stick with Honeywell? Thanks again for your help.