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  1. #1

    VMA 1420 Actual temp set points display wrong values

    My HVACPRO displays the actual cooling \ heating set points at 145 \ 138 F.
    They should be around 73 \ 70 F.

    VAV Box - Temperature Setpoint
    *ADF 13 Actual Cooling Setpt ACLG-SP 145
    *ADF 14 Actual Heating Setpt AHTG-SP 138

    Has anyone run across this before?
    Any suggestions would greatly be appreciated
    Thanks!

  2. #2
    Join Date
    Mar 2005
    Location
    Redding, CA
    Posts
    45
    Looks as though you have values in the the Common Setpoint as well as the Cooling Setpoint and Heating Setpoint. The controller adds them together (along with the bias values) to get the actual setpoints.

    To fix it you need to set Common Setpoint to 0deg and use the Cooling Setpoint and Heating Setpoint. Don't forget to set the heating and cooling bias to 0deg.

    Or you could set the Cooling Setpoint and Heating Setpoints to 0deg and use the Common Setpoint with biases to arrive at the Actuals.

    Just depends on how you want to approach it.

  3. #3
    Join Date
    Sep 2007
    Location
    Michigan
    Posts
    290
    Quote Originally Posted by scc View Post
    Looks as though you have values in the the Common Setpoint as well as the Cooling Setpoint and Heating Setpoint. The controller adds them together (along with the bias values) to get the actual setpoints.

    To fix it you need to set Common Setpoint to 0deg and use the Cooling Setpoint and Heating Setpoint. Don't forget to set the heating and cooling bias to 0deg.

    Or you could set the Cooling Setpoint and Heating Setpoints to 0deg and use the Common Setpoint with biases to arrive at the Actuals.

    Just depends on how you want to approach it.
    More detail, if you open your HVAC pro menu and search you'll find the details in there. I have never ran across a job where the customer, or we have used the Heating/Cooling setpoints.

    Our standard setpoint. I personally am too warm at 72 so if it was my office I'd lower my heating bias.
    Common= 73.0
    Cooling Bias= 1
    Heating Bias= -1
    Actual Heating= 72
    Actual Cooling=74
    if you have your warmer cooler of +/- 5 you have a working range of 67-79

    Actual Heating Setpoint= Heating setpoint + remote adjust + common setpoint + actual heating bias + winter compensation

    Actual Cooling Setpoing=
    cooling setpoint + remote adjust + common setpoint + actual cooling bias + summer compensation.
    "Yeah I can figure out whats wrong with it, but you were here first and there isn't room for two, plus it's cold up here, I'll be in the van"

  4. #4
    Join Date
    Mar 2005
    Location
    Redding, CA
    Posts
    45
    You are correct. However, most of my customers have a hard time with a common setpoint and biases so they get the seperate heating and cooling setpoints which they seem to understand better.

    But as to the original question it appears to me that someone has inadvertantly entered values in both areas to arrive at an actual setpoint double what it should be.

  5. #5

    Thanks

    Thank You all for you input keepyoucool2003 & SCC -
    Excellent feedback!
    I shall check these settings when I get back to the job site.
    I am stuck with using the heat cool set points because they are used for the typical VAV graphics.
    Cheers.

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