CCN Algorithm Heat staging with reset
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  1. #1
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    Confused CCN Algorithm Heat staging with reset

    I have a CC6400 and I'm looking for a way to use the canned algo's to control a 2 stage gas furnace (DO only) and also be able to reset the SAT based on OAT...Any suggestions? I was hoping that the DO-DX Staging VAV Algo could be used by reversing the logic but it does not appear to be an option. Thanks in advance!

  2. #2
    Join Date
    Dec 2012
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    Is your control logic wants to be when OAT and SAT drops then cut in DO? or OAT rise then cut out DO?

  3. #3
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    Quote Originally Posted by junegemini View Post
    Is your control logic wants to be when OAT and SAT drops then cut in DO? or OAT rise then cut out DO?
    Junegemini: I need the DO's to maintain SAT setpoint by opening or droping when sthe SAT rises. I also need the SAT setpoint to reset based on OAT. In a nutshell I would like the Algorithm to behave exactly like the "DO- DX Staging VAV" but for a heat application. I've been trying to piece one together using the other canned algo's without any luck. I don't know Best++, otherwise I would go that route. Thanks!

  4. #4
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    Dec 2012
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    Try changing your proportional term to a postive number instead of negative. Default for DO DX Staging VAV is -5, change it to a postive 5 and it should reverse the logic. Not 100% sure this will work for this algorithm but it does for other adaptive algoritms, and is worth a shot.

  5. #5
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    Quote Originally Posted by xornelasx View Post
    Junegemini: I need the DO's to maintain SAT setpoint by opening or droping when sthe SAT rises. I also need the SAT setpoint to reset based on OAT. In a nutshell I would like the Algorithm to behave exactly like the "DO- DX Staging VAV" but for a heat application. I've been trying to piece one together using the other canned algo's without any luck. I don't know Best++, otherwise I would go that route. Thanks!
    Create one Analog SW pt unit %. Create an AO-Adaptive Control unit dC and use SAT as control sensor and OAT as reset sensor, then follow by two DO-Analog Comparison one for DO1 & the other for DO2 with the Analog SW pt in % as control sensor. Create two setpoints for the DO-Analog Comparison respectively. assume that your 1st DO-Analog Comparison will cut in 0~50% and the 2nd DO-Analog Comparison cut in 51~100%. just adjust the setpoint accordingly. Not sure this can help. Of course using BEST++ will be much more flexible. If you need guide please drop me a mail.

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