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

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Old 10-12-2008, 01:45 PM  
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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
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Old 11-02-2008, 06:29 PM  
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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.
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