Original message
| miller8686
 |  "Trane to Honeywell RTH7400 revisited"
, posted Sun 6 Apr 12:06  
I am switching from a Trane Weathertron Baystat240a thermostat system to the Honeywell RTH7400 digital thermostat system. I read the instructions and followed all directions. My wiring is typical:
B (Blue) 24v Common to C
X2 (Black) EM heat to E
W (White) First stage aux heat to Aux
T (Tan) Outdoor thermister taped up
G (green) Fan to G
O (Orange) Reversing valve to O/B
Y (Yellow) First stage compressor to Y
R (Red) 24v Hot to RC and a jumper goes from here to R
When going through the setup I made the following changes:
0170 - 7, 0190 - 0
Current problem is system blows heat while on cool and heat settings even though I set up the codes.
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Replies:
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| miller8686
| "Re(1):Trane to Honeywell RTH7400 revisited" , posted Sun 6 Apr 14:13
I just wired back in the old Trane Stat again and it works like a champ. All the wires check fine when I spark chase them. Is it worth all the hassle changing over to a programmable unit? Is there a really good recommended brand and model other than Honeywell? I appreciate the help so far. I know it is Sunday and all.
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| | dwcaveney
| "Re(2):Trane to Honeywell RTH7400 revisited" , posted Sun 6 Apr 20:38:
Did you try 190=1 ?
DW
[this message was edited by dwcaveney on Sun 6 Apr 21:22] |
| | miller8686
| "Re(3):Trane to Honeywell RTH7400 revisited" , posted Mon 7 Apr 08:46
Yes I did. I figured I would play with the settings for awhile and see if they make a difference. I set it to 1, cranked down the temp and waited. When the system kicked on it was still blowing heat.
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| | Houston204
| "Re(2):Trane to Honeywell RTH7400 revisited" , posted Sun 6 Apr 14:44
I recommend a VisionPro TH8320 or TH8321
"Tip of the Day" Remember to remove power first.
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| | miller8686
| "Re(3):Trane to Honeywell RTH7400 revisited" , posted Mon 7 Apr 17:55
Oh, I forgot, my best guess would be that I had some wires touching each other in the last install. That is the only thing I can think of that would cause the problems I was having. Hope this helps someone else in the future - (check to make sure wires are not touching before you slap the face on the unit.)
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| | miller8686
| "Re(3):Trane to Honeywell RTH7400 revisited" , posted Mon 7 Apr 17:51
It is fixed. Consider this case closed. Although I'm not sure how. I reconnected the new unit just out of curiosity. I connected the wires exactly how they were before and double checked my work. I turned down the temp and like magic, it works, go figure. I am an aircraft mechanic by trade and I have worked on A/C systems before and this has to be the most interesting fix I have ever seen. I appreciate you helping me. This forum is awesome. I have learned so much about heating and cooling systems just by getting lost in the previous posts. Thank you!
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| | dwcaveney
| "You had a stuck RV memory." , posted Tue 8 Apr 05:38:
When you monkeyed with the 190 option it "fixed" the reversing valve in the honeywell memory.
DW
[this message was edited by dwcaveney on Tue 8 Apr 05:45] |
| miller8686
| "Re(1):Trane to Honeywell RTH7400 revisited" , posted Sun 6 Apr 12:44
Sorry, I should have been more specific. I named the post revisited because I found other posts directly relating to this problem. I followed the coourses of action and I am still unable to resolve the heat blowing in all modes. I did trace most of the wires, they are fine, and the system works fine with the old theromstat. So, I am at a loss as to what the problem might be.
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| | Houston204
| "Re(2):Trane to Honeywell RTH7400 revisited" , posted Sun 6 Apr 13:00:
Sounds like you have a bad stat. If you are confident that your orange wire was wired in to O/B correctly and configured to 170 = 7 and 190 = 0, return it.
"Tip of the Day" Remember to remove power first.
[this message was edited by Houston204 on Sun 6 Apr 13:13] |
| Houston204
| "Re(1):Trane to Honeywell RTH7400 revisited" , posted Sun 6 Apr 12:37
Does revisited mean that it did work for a while?
If so...
Verify that your orange wire is not cut. I would start outside.
Do you own a meter? You can measure for 24 volts between O and C outside.
"Tip of the Day" Remember to remove power first.
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