new thermostat - http://www.hvacmechanic.com/ Forums

Original message

jfrank2255

76.181.198.8

"new thermostat" , posted Sat 2 Feb 10:47:

I want to replace my old lennox thermostat #51H4701 with a honeywell vision pro TH8320U1008 TOUCH SCREEN with the same results as the old lennox 51H4701. The system settings on the 51H4701 are, for my primary heat, gas furnace, HEAT, AUTO,EMERGENCY HEAT. For my auxillary heat (heat pump) my system is set to HEAT,AUTO,NORMAL. For my air condition(heat pump) my system is set to COOL, AUTO NORMAL. This system was installed in 1991 and has worked just fine. So is it possible to wire TH320U1008 without any major wire changes at the furnace level? Wire connections on the 51H4701 are wire color to thermal#-- black to O , blue to R , green to G ,red to y-1 , orange to w-1 yellow to c. My furnace is a lennox pulse installed in 1991. The reason that I use my gas furnace as my primary heat is because I have my own gas well. My furnace is single stage and my heat pump is single stage.

Tank you so much for your help Whitey

[this message was edited by jfrank2255 on Sat 2 Feb 12:35]

Replies:

yuri

207.161.216.119

"Re(1):new thermostat" , posted Sat 2 Feb 13:37:

Hang in there bud. Our expert tech Houston 204 will be online later and help you. I don't do heat pumps.

Yuri

[this message was edited by yuri on Sat 2 Feb 13:37]

Houston204

98.196.66.53

"Re(2):new thermostat" , posted Sat 2 Feb 20:47

That is a strange color code that you are using. When I Googled your thermostat, I was sent back to this site, and the other posts used a standard color code.

Terminal = wire
Aux & E = orange
Rc & R = blue
O/B = black
Y = red
G = green
C = yellow

Option = setting
120 = 20
130 = 08
140 = 2 (month)
150 = 2 (todays date)
160 = 4
170 = 7
180 = (will not appear)
190 = 0 (if it is a Lennox, Carrier, Trane, Goodman, ICP)
200 = 1
210 = 1 (0 if you get the recommended outdoor sensor)
220 = 3
240 (will not appear)
250 = 5
270 = 5
280 = 1
300 = 1
310 = 3
320 = 0
330 = 2
340 = 0 (I recommend an outdoor sensor)
340 = 0
350 will no appear
360 will not appear
500 = 1 for most applications (3 for Honeywell mechanical filters)

I don't see a setting that will allow gas heat as stage 1 and heat pump as stage 2.

"Tip of the Day" Remember to remove power first.

Houston204

98.196.66.53

"Re(3):new thermostat" , posted Sat 2 Feb 20:51:

If I had free gas I'd wire the black wire to R along with the blue wire and configure option 170 to 1 and 180 to 0.

"Tip of the Day" Remember to remove power first.

[this message was edited by Houston204 on Sun 3 Feb 13:30]

jfrank2255

76.181.198.8

"Re(4):new thermostat" , posted Sat 2 Feb 21:39

You say to wire the black wire to R along with the blue wire ok but what terminals do I connect the red,yellow and the orange wire to. I assume the green goes g. Also should I jump Rc and R together. One thing I do know how to do is program the options believe it or not ha

Tank you so much for your help Whitey

Houston204

98.196.66.53

"Re(5):new thermostat" , posted Sun 3 Feb 02:52

Terminal = wire

Rc & R = blue and black (leave the jumper in as well)
O/B = orange
Y = red
G = green
C = yellow

170 = 1
180 = 0

This will basically control your system as a gas heat system.

"Tip of the Day" Remember to remove power first.