Original message
| patrickmhurley
 |  "Honeywell to Lux tx500b - Please Help!"
, posted Tue 27 May 22:54  
I've been searching this forum for the better part of the last two hours...I read as many posts as I could but couldn't find a resolution, so if anyone out there can help I would greatly appreciate it.
PROBLEM: Fan will only blow hot air from vents after installing Lux tx500b digital thermostat from Honeywell mercury thermostat.
CURRENT LUX TX500B CONFIGURATION:
G: Green Wire
Y: Yellow Wire
W: White Wire
RH: Red Wire (via jumper)
RC: Red Wire
UNUSED WIRES:
BLUE, BLACK, ORANGE, PINK, 2X GREY
Pump outside and fan both are operational, AC is not. Any suggestions for a guy sweating through his shirt??
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Replies:
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| dwcaveney
| "Re(1):Honeywell to Lux tx500b - Please Help!" , posted Tue 27 May 23:16:
Lot of wires. Is it a heat pump or gas heat? That stat won't run a heat pump and AC.
It will work with gas heat and AC, and if thats what you got, sounds like its hooked up right.
Check your air handler and make sure the wires are correct there.
How was the old one connected?
Turn off the breaker and wait ten minutes, then turn it back on.
http://www.luxproducts.com/ART/support/TX500b_Eng_WebManual.pdf
DW
[this message was edited by dwcaveney on Tue 27 May 23:25] |
| | Houston204
| "Re(2):Honeywell to Lux tx500b - Please Help!" , posted Tue 27 May 23:54:
It sounds like a heatpump.
Post the model number of your old stat(Honeywell T841A or subbase Q674L????) along with the terminal = color combination of the old stat.
The Honeywell RTH7400 or RTH7500 with autochangeover are programmable stats compatable with heat pumps.
"Tip of the Day" Remember to remove power first.
[this message was edited by Houston204 on Wed 28 May 00:00] |
| | Houston204
| "Re(3):Honeywell to Lux tx500b - Please Help!" , posted Wed 28 May 00:01
Color codes vary, post your old combination and model.
"Tip of the Day" Remember to remove power first.
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| | patrickmhurley
| "Re(4):Honeywell to Lux tx500b - Please Help!" , posted Wed 28 May 10:58
Thank you all for your quick responses. I really appreciate it. Unfortunately, I don't have the model number of the old mercury Honeywell stat, nor do I have the previous wiring configuration :(
I was hoping that there was a similar enough scenario out there, but as a noob, I'm getting the sense that each of these cases is it's own animal. Everything is operation except the air conditioning, so I'm wondering if it's a matter of just figuring out the Y and W ports and their corresponding wires (the AC was completely functional before the fateful switch).
If I can't get this unit to work is there a manufacturer or model that anyone would recommend that is more accomodating to a 9/10 wire interface from circa 1990? Thanks again to everyone for their time and attention
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| | dwcaveney
| "If you want help, answer the question" , posted Wed 28 May 14:30:
The Honeywell model THERMOSTAT right above your post is the one that our t-stat expert Houston204 recommends!
Do you have a HEAT PUMP?
You said you read the posts, but it's not sinking in.
A heat pump is an air conditioner run backwards!
THE THERMOSTAT YOU HAVE WILL NOT RUN A HEAT PUMP AND AC, BECAUSE THERE IS NO CONNECTION ON THAT T-STAT FOR A REVERSING VALVE!!!!!!!
Your t-stat could run AC and a heat pump, but you would need $1200 for circuit design and parts, $1500 for install and testing, and Albert Einstein's or one of our tech's phone number.
EDIT: Just kidding, glad you got it figured out.
Many of us, when we were new guys, have pulled out thermostats without marking the existing wires. Makes it complicated to hook up the new stat. One feels really dumb, trying to explain to the customer why the system won't work until tomorrow.
The first paragraph in every install sheet always says, mark the existing wires with the little stickies that come with the stat.
DW
[this message was edited by dwcaveney on Thu 29 May 00:29] |
| | patrickmhurley
| "Re(1):If you want help, answer the question" , posted Wed 28 May 14:47
My apologies. I do have a heat pump. And I read the previous post from my handheld which didn't download the entire post. Sorry for any confusion this caused and I really appreciate the imput and the suggested alternative models. Thanks everyone.
- Patrick
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