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Thread: 2 units 1 stat

  1. #1
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    2 units 1 stat

    I could use some advise. How can you control 2 units with 1 stat?

    I have 2 situations, one is a classroom building that only has single phase power.
    Classroom:PE designs system with 1 supply duct with 2 Trane wcz048 heat pumps. Each has a 2 stage compressor.
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    How would you control these units? This equipment will be tied into the schools EMCS.

    The second situation is a residence with 2 units serving a great-room with walls of glass.
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    It would be simple enough to twin the furnaces but I would like to stage the single stage condensers with a single control instead of adjusting set points.
    Your suggestions would be greatly appreciated
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  3. #3
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    Wow, for a minute I thought this might be a twisted version of a shock video or something.

  4. #4
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    Quote Originally Posted by Control Man View Post
    Thanks for the link.
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  5. #5
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    You could also install a 2H/ 2C stat and a seperate control transformer and wire one 1st stage and the other 2nd stage. I have a system like this and I run continus blower on both to keep temps even.

  6. #6
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    After reviewing the Jackson kit TK-400. It appears that it would be the way to go for the resi install with 2 units with 2 seperate supply ducts and standard blower motors. With the classrooms however these units are variable speed blower motors and the install guide says not to use the TK-400 with vs motors. I wonder why?
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  7. #7
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    Quote Originally Posted by perfectionist View Post
    You could also install a 2H/ 2C stat and a seperate control transformer and wire one 1st stage and the other 2nd stage. I have a system like this and I run continus blower on both to keep temps even.
    I would possibly do this on my own stuff. Both of these jobs are going to receive a high level of scrutiny therefore I am going to do whats referred to as "current industry standard"............. or better.
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  8. #8
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    Quote Originally Posted by ACFIXR View Post
    After reviewing the Jackson kit TK-400. It appears that it would be the way to go for the resi install with 2 units with 2 seperate supply ducts and standard blower motors. With the classrooms however these units are variable speed blower motors and the install guide says not to use the TK-400 with vs motors. I wonder why?

    Variable speed motors and twinning:http://hvac-talk.com/vbb/showthread....1#post12832611

    something is wrong with me, i am answering my own post's.
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