programable thermostat

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Posts: 1
Joined: Fri Dec 18, 2009 12:07 pm

Tue Dec 22, 2009 10:59 am

wanting to install programable thermostat in home. my question is-we have 2 seperate units : a selfcontained a/c outside and selfcontained heat inside. both have thier own thermostat (side by side on wall). will i need 2 programable therostats or will 1 control both. with both being indepentant units,we have had both units come on at same time(gotto love the weather in lower alabama) from what i have read the instructions on the thermostats say they will control both heating and cooling but the wiring diagrams seem to be for one thermostat. i dont have the make of both models but will get if needed, just a general question on installation.thank you james baker andalusia alabama

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Joined: Wed Feb 28, 2007 12:07 am
Location: Tennessee

Tue Dec 22, 2009 12:01 pm


You can install one to control both. Will need to get one that is battery operated or run a common wire from transformer secondary-common side to the t-stat C connection.

Should also get one with a lockout feature to prevent both units from being on at same time.

Also, be sure you have a close off damper where the supply duct from a/c unit connects to main home duct and also underneath the the inside furnace.

These are needed when you have a self-contained a/c unit outside and an inside furnace.

I would get a Honeywell or White-Rodgers t-stat and going to an hvac supply would ensure you get correct one for what you have.

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