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  1. #1

    Honeywell TH8320 with strange configuration

    I am connecting a Honeywell TH8320 Tstat to a Carrier Heat pump system that uses a Carrier FK4 FCU (variable spd fan). The current system has the heat pump with electric elements as emergency/back up, and I have added a hot water coil to the duct that I am using as aux heat. I thought this woud be a no-brainer, but carrier and honeywell seem to use somewhat different terminals. Here are my questions:
    (1) Should I use the honeywell "E" to connect to the Carrier W1/W2? so that the electric elements remain the emergency heat?
    (2) The "Aux" contacts I am using to energize a 24 v relay that activates the hydronic zone that provides water to the new duct coil (and activates "G" on the fan coil unit to run the fan in slow spd). Does that seem OK?
    (3) The honeywell install manual uses different terminology in different parts. On page 10, in the "installer system test" section, refers to stages 1,2,3. Does Stage 1, 2, 3 mean the same thing as Stage 1 = heat pump, Stage 2 = Aux heat, and Stage 3 = emergency heat?
    4) Finally, I have been asuming that the variable speed fan will still function in the normal heat pump mode because the circuit for that lives in the FCU vice the carrier thermostat. Is that correct?

    Thanks for your help on any or all of the questions,

  2. #2
    Join Date
    Jul 2008
    Dutchess County, NY
    you cannot run a zone valve off that tstat while operating a heat pump with 2 stage compressor ... on a call for heat w1 aux and E are energized. no way to seperate them

    Y1 = 1st stage heat/cool
    Y2 = 2nd stage heat/cool
    W1= 3rd stage heat
    Aux/E = Emergency heat

  3. #3
    Join Date
    Jan 2004
    A. I don't see where he said he has a 2 stage compessor.

    B. No DIY instructions allowed.
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    How many times must one fix something before it is fixed?

  4. #4
    Join Date
    Jun 2008
    west point, ga.
    We cannot give this info on open form.If you are in the biz get 15 post and apply for pro status and we can tell you the answer you seek.By the way your problem is not that hard to figure out.

  5. #5
    Sorry, I didn't realize I was violating posting rules. You are right, It isn't a 2 stage compressor. And I got it working ok now with a couple of trials. I'm not a pro, just someone who installed a radiant system and wanted it to interface with the heat pump system. Works great and I got rid of the annoying high speed fan when the electric elements kicked in on cold days.

  6. #6
    Join Date
    Jul 2008
    Dutchess County, NY
    hey ... glad you got it working... I would like to know how you got it working though... if you dont mind, send me an email so we can discuss it...I have the same tstats and a similar situation. unfortunately, we cannot discuss it here.

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