DIY Home Improvement, Remodeling & Repair Forum > DIY Home Improvement > HVAC > Thermostat wire codes don not match

Thread Tools Search this Thread
Old 10-12-2008, 01:45 PM  
Junior Member
Join Date: Sep 2008
Posts: 6
Default Thermostat wire codes don not match


I'm attempting to install a Honeywell programable thrmostat to replace my old mercury white rogers t stat.

When I pull the old T stat it has 4 wires coded as follows

The new thermostat mentions RH and W wires but I'm nit sure what the T1 and T wires are for. My guess is a timer as the old TStat had a timer and did not use batteries. I'm tempted to just cap them and go on with the install.

Anyone have any ideas?


Last edited by ufatbasted; 10-12-2008 at 01:47 PM. Reason: typo
ufatbasted is offline  
Reply With Quote
Old 11-02-2008, 06:29 PM  
Katonah Medic
All Thumbs
Katonah Medic's Avatar
Join Date: Oct 2008
Posts: 9

I just replaced my old mercury stats with the same Honeywell P'gramable stat.

My 24v system only has two wires.

The Rh and W are the only ones you need to have it run, assuming its heat only and hot Heat/Cool.

Check the transformer on your zone circulator and you should see only 2 wires attached..

This may be a late post. Let us know how it worked out for you.
Katonah Medic is offline  
Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Similar Threads
Thread Thread Starter DIY Home Repair Forum Replies Last Post
Electric Heat Pump & Programmable Thermostat John Greeb HVAC 2 01-09-2009 10:01 PM
Thermostat wire codes do not match ufatbasted Electrical and Wiring 2 10-12-2008 08:23 PM
Thermostat wire for gas fireplace Outbacker HVAC 5 11-04-2007 11:57 AM
Thermostat Installation jeff7 HVAC 3 01-22-2007 10:31 AM
Having trouble wiring thermostat swinny Electrical and Wiring 2 11-29-2006 10:08 PM