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  1. #1
    Join Date
    Nov 2012
    Posts
    8

    Thermostat recommendation for Heat Pump + odd wiring setup

    Hello, new member here on hvac-talk and seeking some guidance about the HVAC system that is setup in my home. This is for a 3400 sq foot home built in the 80s with 2 large Carrier heat pumps, 2 air handlers with resistance heat backup, and 3 zones total.

    There are 3 thermostats in the house right now. Two of them are the original 80s, non digital thermostats. One of them was upgraded at some point with a lower end digital unit that we find very confusing to use. There is also a main switch for the entire house which controls whether the systems are in heating or cooling mode. I believe that this switch can also be used to force the systems into backup heating mode only (not too sure). I have never seen anything like this before.

    We would like to replace the thermostats in the house and I am seeking some guidance on what thermostat to use. We want a unit that will give us complete control over the HVAC system. My requirements are as follows:

    - manual shutoff for resistance heat
    - programable setback for the resistance heat, ie. so that I can limit how often the backup heat turns on
    - programmable schedules
    - exterior temp sensor with heating algorithm to limit the use of the resistance heat
    - multiple wireless interior temperature sensors

    The manual shutoff for the resistance heat is important for us. We lost power for 9 days as a result of hurricane Sandy and dealing with the HVAC system was a big problem while running on our generator since I couldn't prevent the resistance heat from turning on.

    Any input about the main control switch would be great as well. We are not sure if this is going to be a problem for the new thermostats. I don't really understand why it is necessary to have that switch but I am not sure what would be involved in removing it or if it is even worth bothering.

    thank you for your help!

  2. #2
    Join Date
    May 2008
    Location
    Missouri
    Posts
    3,322
    I would try and find the original installing contractor (who knows the system) and have them address your questions. Way too many variables for us to recommend anything from here!

  3. #3
    Join Date
    Nov 2012
    Posts
    8
    Quote Originally Posted by wahoo View Post
    I would try and find the original installing contractor (who knows the system) and have them address your questions. Way too many variables for us to recommend anything from here!
    Well - that is kind of the route that I started with as well. I have no idea who originally installed the system since it was done almost 30 years ago and this is sort of a one-off custom house. I did reach out to the company that I believe replaced one of the air handlers (possibly the heat pumps as well, but I don't know) for the prior owner but I am not so sure how familiar they are with the whole system.

  4. #4
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    3,958
    Ecobee is one of the most veristile stats you can buy...
    However for your unique setup a pro thats excellent with control circuits will be required to hook it up.

  5. #5
    Join Date
    Nov 2012
    Posts
    8
    Quote Originally Posted by 54regcab View Post
    Ecobee is one of the most veristile stats you can buy...
    However for your unique setup a pro thats excellent with control circuits will be required to hook it up.
    Interesting, I was not aware of this product. Does the Ecobee give more end user control than something like the Honeywell VisionPro IAQ or the Prestiage IAQ thermostats?

    Any advice about how to locate a pro in my area that specializes in Control circuits? What should I be asking for? I am in Fairfield County, CT if anyone can suggest someone.

  6. #6
    Join Date
    Dec 2007
    Posts
    4,575
    Quote Originally Posted by stook1 View Post

    Any advice about how to locate a pro in my area that specializes in Control circuits? What should I be asking for? I am in Fairfield County, CT if anyone can suggest someone.
    we have a contractor locator on this website, one link above this area.

    I would also agree that a controls or very knowledgeable tech is needed. Explain your situation when talking to the company(ies) to assure a better chance you get the right person the first time.
    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
    from an excerpt by Paul Jacob in Sun City, AZ

  7. #7
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    3,958
    Quote Originally Posted by stook1 View Post
    Interesting, I was not aware of this product. Does the Ecobee give more end user control than something like the Honeywell VisionPro IAQ or the Prestiage IAQ thermostats?

    Any advice about how to locate a pro in my area that specializes in Control circuits? What should I be asking for? I am in Fairfield County, CT if anyone can suggest someone.
    The Ecobee has many similar features of the Honeywell IAQ. Both are excellent products, choose the interface/features you like best.

  8. #8
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    33,398
    - manual shutoff for resistance heat
    - programable setback for the resistance heat, ie. so that I can limit how often the backup heat turns on
    - programmable schedules
    - exterior temp sensor with heating algorithm to limit the use of the resistance heat
    - multiple wireless interior temperature sensors
    I'm not sure how much of this you'll find. Switchable backup is usually only done by outdoor sensor and you saying don't allow backup below a set outdoor temp. Same with any kind of control of backup during programming. Never seen this. Modern stats try to avoid backup coming on but if the heat pump isn't warming the house back up fast enough, they all turn it on unless locked out by an outdoor temp setting. The Prestige IAQ in commerical mode does have a way for it to base outdoor temp into the recovery factor. The manual is vague on this but some of the boys who know Honeywell commercial controls might be able to elaborate.

  9. #9
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    3,958
    The ecobee has 3 settings to control AUX heat. One is time the heat pump runs before trying AUX heat. The other is degrees below setpoint before turning on AUX heat. It also can lock out AUX heat based on outdoor temperature. All 3 strategies can be combined.

    For instance you could make a strategy such as: Do not run AUX heat unless it's colder than 40 outside, the heat pump has been running 30 minutes, and it's 5 degrees below indoor setpoint.

  10. #10
    Join Date
    Dec 2007
    Posts
    4,575
    Quote Originally Posted by 54regcab View Post
    The ecobee has 3 settings to control AUX heat. One is time the heat pump runs before trying AUX heat. The other is degrees below setpoint before turning on AUX heat. It also can lock out AUX heat based on outdoor temperature. All 3 strategies can be combined.

    For instance you could make a strategy such as: Do not run AUX heat unless it's colder than 40 outside, the heat pump has been running 30 minutes, and it's 5 degrees below indoor setpoint.
    I am sure this can be done with the Prestige as well.
    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
    from an excerpt by Paul Jacob in Sun City, AZ

  11. #11
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    3,958
    Quote Originally Posted by pacnw View Post
    I am sure this can be done with the Prestige as well.
    I don't doubt it.

  12. #12
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    5,996
    Quote Originally Posted by stook1 View Post
    Any advice about how to locate a pro in my area that specializes in Control circuits?
    What should I be asking for?
    I am in Fairfield County, CT if anyone can suggest someone.
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