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  1. #1

    Thumbs up Solar Control Needed

    We are installing a special heating coil into a clients plenum that circulates solar heated hot water and need to control a circulation pump and the furnace fan. Looking for the simplest control to do to do this.

    Logic of the needed control is that when the temperature in the hot water storage tank is more than a settable amount, let say X (about 100deg), and we get a heat call need to turn on the 110v a/c circulation pump and the furnace fan, however, if the temperature in the tank is not X then I need to fall back to normal furnace operation.

    I found a 24Volt control (Johnson Control A419) that can sense the temperature in the tank and turn on a power-strip that would be connected to the 110V a/c pump. This would give the control that is needed however it would not give me the fall-back logic when the temperature is not X to fall-back to normal furnace operation.

    Suggestions for a thermostat or control would be appreciated

  2. #2
    Join Date
    Oct 2003
    Location
    Valdosta Ga
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    847

    Smile

    There is a 30,000 btu coil with circulation pump on the market. It's for folks with heat pumps that want to use hot water for 2nd stage heat.
    i am sorry I don't know who makes it.

  3. #3
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,270

    Wink NC Relay

    Quote Originally Posted by REEngineering View Post
    We are installing a special heating coil into a clients plenum that circulates solar heated hot water and need to control a circulation pump and the furnace fan. Looking for the simplest control to do to do this.

    Logic of the needed control is that when the temperature in the hot water storage tank is more than a settable amount, let say X (about 100deg), and we get a heat call need to turn on the 110v a/c circulation pump and the furnace fan, however, if the temperature in the tank is not X then I need to fall back to normal furnace operation.

    I found a 24Volt control (Johnson Control A419) that can sense the temperature in the tank and turn on a power-strip that would be connected to the 110V a/c pump.

    This would give the control that is needed however it would not give me the fall-back logic when the temperature is not X to fall-back to normal furnace operation.

    Suggestions for a thermostat or control would be appreciated
    A ( NC ) Normally Closed relay _ in series _ with the furnace thermostat held Open when the circulation pump is running would be appropriate if sized and selected for the specific application requirements.
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  4. #4
    Join Date
    Dec 2005
    Location
    Memphis, TN.
    Posts
    823
    Quote Originally Posted by bzzline View Post
    There is a 30,000 btu coil with circulation pump on the market. It's for folks with heat pumps that want to use hot water for 2nd stage heat.
    i am sorry I don't know who makes it.

    Would like to know this info if someone comes across it please!

    Thanks,

    CW.

    PS:

    Email in profile.....
    "I don't care what you could get it off the net for, they wont warranty it and neither will I"!

    And if you don't like my "flat rate up front pricing" try and negotiate the price on that big mac you just bought pricing is exactly the same method!

  5. #5
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    67,870
    I found a 24Volt control (Johnson Control A419) that can sense the temperature in the tank and turn on a power-strip that would be connected to the 110V a/c pump. This would give the control that is needed however it would not give me the fall-back logic when the temperature is not X to fall-back to normal furnace operation.


    Yes it would.
    It has an adjustable differencial. So that when the temp drops, it would energize the normal heating circuit.

    It has NC, and a NO circuit.
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  6. #6

    Thank you, time to take a closer look

    Thanks to all of you who responded, appreciate the advice. Looks like I'll have to think about this and come back and answer posts....

    Can definitely do the job that is needed with two A419 Johnson Controls and not use the thermostat at all and just set it a degree or so lower and use the thermostat the way it is as the fall-backup, but really want to incorporate just one device to do all the controls, and perhaps in addition a sensor.

    Thank you all once again. Any additional thoughts are greatly appreciated.

  7. #7
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,870
    What is the primary sourse of heat.
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  8. #8
    Join Date
    Oct 2003
    Location
    Valdosta Ga
    Posts
    847

    Hmm

    This is not the coil I saw but it may help with a Ideahttp://www.firstco.com/products/vhbqb.asp

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