Thermostatic Controls - 2 Thermostats, One Furnace
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turbojimmy
10-01-09, 04:43 AM
Hi all,
I recently moved into a home where the previous owner had installed 2 thermostats on a single furnace. It has central air, too. The upstairs thermostat appears to be the only one that can control the A/C as there is a blue and a green wire attached to it that are missing from the downstairs thermostat. Now that it's cold, and I've switched to heat, I'm finding that only the downstairs thermostat is controlling the heat. The furnace will only run if that thermostat is calling for heat. I understand that these are basically just switches, but I'm wondering if there is a way to get them to work in a way that heat and a/c will come one if EITHER calls for it. I would assume that I'd need to run some kind of common wire, like a 3-way electical circuit.
TIA for any advice.
Jim
I recently moved into a home where the previous owner had installed 2 thermostats on a single furnace. It has central air, too. The upstairs thermostat appears to be the only one that can control the A/C as there is a blue and a green wire attached to it that are missing from the downstairs thermostat. Now that it's cold, and I've switched to heat, I'm finding that only the downstairs thermostat is controlling the heat. The furnace will only run if that thermostat is calling for heat. I understand that these are basically just switches, but I'm wondering if there is a way to get them to work in a way that heat and a/c will come one if EITHER calls for it. I would assume that I'd need to run some kind of common wire, like a 3-way electical circuit.
TIA for any advice.
Jim
Jay11J
10-01-09, 01:14 PM
Jim.
There is no t-stat like a "3-way switch" setting. Are we talking a 2 story house or rambler and other t-stat in the basement?
There is a way that you can use the one t-stat as heat and cool, and other one just heat. But a relay is needed and can get complex to wire up this way.
I am guessing the two stat was done was due to poor ductwork (comfort) in the home and this is a make shift zone system in a way.
I am going to say, maybe get rid of the one t-stat and just use the one.
There is no t-stat like a "3-way switch" setting. Are we talking a 2 story house or rambler and other t-stat in the basement?
There is a way that you can use the one t-stat as heat and cool, and other one just heat. But a relay is needed and can get complex to wire up this way.
I am guessing the two stat was done was due to poor ductwork (comfort) in the home and this is a make shift zone system in a way.
I am going to say, maybe get rid of the one t-stat and just use the one.
turbojimmy
10-01-09, 02:39 PM
Jim.
There is no t-stat like a "3-way switch" setting. Are we talking a 2 story house or rambler and other t-stat in the basement?
There is a way that you can use the one t-stat as heat and cool, and other one just heat. But a relay is needed and can get complex to wire up this way.
I am guessing the two stat was done was due to poor ductwork (comfort) in the home and this is a make shift zone system in a way.
I am going to say, maybe get rid of the one t-stat and just use the one.
Thanks for the reply.
It's a bilevel house with poor ducting. Upstairs gets hot in the winter, downstairs is freezing cold. Ditto with the AC running - all the cool air is downstairs. I guess the second thermostat (the downstairs one) was an attempt to at least keep the downstairs warm in the winter. The way they're wired up now, the upstairs stat does cooling and the downstairs one does the heating. I guess that's as good as it gets. I'm renting the place so I don't want to make a huge investment in improving the situation. I'll just keep a fire going downstairs to keep that thermostat warm :-)
Jim
There is no t-stat like a "3-way switch" setting. Are we talking a 2 story house or rambler and other t-stat in the basement?
There is a way that you can use the one t-stat as heat and cool, and other one just heat. But a relay is needed and can get complex to wire up this way.
I am guessing the two stat was done was due to poor ductwork (comfort) in the home and this is a make shift zone system in a way.
I am going to say, maybe get rid of the one t-stat and just use the one.
Thanks for the reply.
It's a bilevel house with poor ducting. Upstairs gets hot in the winter, downstairs is freezing cold. Ditto with the AC running - all the cool air is downstairs. I guess the second thermostat (the downstairs one) was an attempt to at least keep the downstairs warm in the winter. The way they're wired up now, the upstairs stat does cooling and the downstairs one does the heating. I guess that's as good as it gets. I'm renting the place so I don't want to make a huge investment in improving the situation. I'll just keep a fire going downstairs to keep that thermostat warm :-)
Jim