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  1. #1
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    Feb 2015
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    Two Thermostats - One furnace

    Hi-

    An issue we are having in the colder months is the following:

    The main room where the thermostat is drops to 66. The heat kicks on to reach 70.

    Then, the kids rooms jump to 76 to 78 by the time the main area reaches 70.

    So, I would like the ability to have the kids room control the furnace.

    One idea I have is to wire two thermostats, not in a series, to the furnace.

    Then, use the "Off" switch on either the kids thermostat or livingroom thermostat, depending on which one is not being used.

    Is this feasible? Any other suggestions? Also, what if both thermostats were set to on?

  2. #2
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    Feb 2015
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    Lennox, South Dakota
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    You need to contact a contractor and have them look at setting up Zones in the duct work to help control where the heat is going. If you were to get 2 t-stats, you might be able to control one room or the other but not both. Kids room might be 70, but the rest of the house might be really cold.
    Mike

  3. #3
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    Sep 2002
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    You can put two thermostats in parallel on one system, but I don't recommend it:

    You need to balance the system - partially close off the vents in the kids rooms.

    You could also try a thermostat with a much lower swing - anything made by honeywell will do.

    Some people run the fan continuously to balance out temps, but that can set you back hundreds of dollars per year.

    -----------------
    Zoning is a band-aid and if your ducts are already undersized for the furnace or heatpump, it's the worst thing you can do.

    If your ducts are completely accessible (in a unfinished basement, crawlspace or attic) making changes to the ductwork might be an option. Bet you that the system wasn't designed right to begin with.
    General public's attitude towards our energy predicament: "I reject the reality of finite resource depletion and substitute it with my own; energy is infinite, we just need an alternative storage medium to run the cars on. The economy can grow indefinitely - we just need to "green" everything! Technology is energy! Peak what?"

  4. #4
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    Feb 2015
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    Quote Originally Posted by amd View Post
    You can put two thermostats in parallel on one system, but I don't recommend it:

    You need to balance the system - partially close off the vents in the kids rooms.

    You could also try a thermostat with a much lower swing - anything made by honeywell will do.

    Some people run the fan continuously to balance out temps, but that can set you back hundreds of dollars per year.

    -----------------
    Zoning is a band-aid and if your ducts are already undersized for the furnace or heatpump, it's the worst thing you can do.

    If your ducts are completely accessible (in a unfinished basement, crawlspace or attic) making changes to the ductwork might be an option. Bet you that the system wasn't designed right to begin with.
    Thanks.

    With regards to balancing, we've noticed that in our main living area, the vents have low pressure, while the bedrooms have high pressure.

    I think you are right about the system not being done properly.

    Where would you even begin to address the main area not getting enough air? Would you have add more vents from the high pressure ducts?

  5. #5
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    Feb 2015
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    Thanks for the note. So, I really don't care if the rest of the house gets cold at night. But I now believe it is out of balance. Would it be effecting the balancing with the fact that the basement vents are shutoff because we don't go down there too much?

  6. #6
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    Apr 2003
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    Maple Grove, MN
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    You could also get a thermostat that has the ability to have averaging sensors hooked up to it. There are some higher end Honeywell thermostats that can even do it wirelessly. That way you can keep the main stat located where it is, and add remote sensors elsewhere, and the system will attempt to average out the temperatures somewhat between the rooms.

    Of course, fixing your duct issues and/or getting a zoning system installed would work better, but this might be an option.

  7. #7
    Join Date
    Apr 2011
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    North Florida
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    Quote Originally Posted by snakepit View Post
    Hi-

    An issue we are having in the colder months is the following:

    The main room where the thermostat is drops to 66. The heat kicks on to reach 70.

    Then, the kids rooms jump to 76 to 78 by the time the main area reaches 70.

    So, I would like the ability to have the kids room control the furnace.

    One idea I have is to wire two thermostats, not in a series, to the furnace.

    Then, use the "Off" switch on either the kids thermostat or livingroom thermostat, depending on which one is not being used.

    Is this feasible? Any other suggestions? Also, what if both thermostats were set to on?
    I did this a long time ago in a house I had. The thermostat wiring has to be run in parallel . I never had any trouble after I did this. BUt perhaps a simplier way of doing it for you, would be to simply close down a bit on the branch supply duct damper feeding your kids room or the registers feeding your kids room as a last alternative. Im assuming you don't have anymore than 2 supply registers feeding your kids room so closing them down a little shouldn't upset the rest of the system.

  8. #8
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    Feb 2015
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    so are you saying in the room close those vents, or adjust the supply line that goes to the vents?

    also, does two parallel thermostats cause problems if both are on and telling the hvac to run? thus it would have to circuit completions. would the double the energy and burn something out?

  9. #9
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    With regards to balancing, we've noticed that in our main living area, the vents have low pressure, while the bedrooms have high pressure.
    You need to damper off the vents that are getting a lot of airflow.

    Be careful though - closing too many vents can cause problems with the equipment.
    General public's attitude towards our energy predicament: "I reject the reality of finite resource depletion and substitute it with my own; energy is infinite, we just need an alternative storage medium to run the cars on. The economy can grow indefinitely - we just need to "green" everything! Technology is energy! Peak what?"

  10. #10
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    Nov 2001
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    east kansas
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    You can. I've used a toggle switch in the past. You could do it with a wireless thermostat. I installed one before but don't recall the details. The customer could detach it from the wall and move it to the room they wanted to control.

  11. #11
    Join Date
    Apr 2011
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    North Florida
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    Quote Originally Posted by snakepit View Post
    so are you saying in the room close those vents, or adjust the supply line that goes to the vents?

    also, does two parallel thermostats cause problems if both are on and telling the hvac to run? thus it would have to circuit completions. would the double the energy and burn something out?
    Use the supply duct damper to pinch down on the airflow if you have a damper otherwise, pinch down on the two registers feeding the room.

    I never had any problems if both of my thermostats called for heat at the same time. The thermostat heat anticipator didn't burn out. A toggle switch is smart though so only one thermostat at a time can run the gas valve.

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