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  1. #1
    Join Date
    Aug 2006
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    2,552

    Pre/Free Cooling with MAU

    I have a McQuay Model RDS800 BY that they are using for 100% make-up air, "Yeah, I know it is totally wrong for the application, but they aren't going to change it out." It has a Preheat and Reheat water coils in it. They were running AHU 24/365. I rewired it and placed it back on the T7300 room stat, and replaced the modulating valve controls, added a freeze stat and replaced the original freeze-stat. Now it runs during the day with Damper 100% open, fan running continously. At night damper is closed, when the unit calls for heat, OA Damper opens 5%, fan runs in "Auto", till heat is satisfied, at 55 F. I would like to Pre/Free cool the kitchen starting at 0400, without running the exhaust fan. The Air handler has Relief baffles, and dampers. Figure I'd get the T7300 to call for cooling and fan at night, set 68 F. The cooling signal would go thru an existing time clock, that's not being used, thru a low limit outdoor air thermostat, to a Cool relay that would open O.A. Damper 100% Does this sound like a good set up ? BTW they do 90% of their cooking in that section of the kitchen in the morning.
    Last edited by madhat; 07-31-2010 at 03:44 PM.

  2. #2
    Join Date
    Jul 2009
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    In my opinion I would say you did a great job with this setup. Does this satisfy guidelines for make-air guidelines? This I do not know. I would think you would get a better response to this in the commercial HVAC thread.

  3. #3
    Join Date
    Aug 2006
    Posts
    2,552
    Quote Originally Posted by pdrake65 View Post
    In my opinion I would say you did a great job with this setup. Does this satisfy guidelines for make-air guidelines? This I do not know.
    When I wrote the sequence of operation, I wrote myself out of the operation of the hoods, wash down, Ansul system, DD, smoke detectors and air flows. The System was never tested and balanced. I wrote up sequence and made wiring digrams over four years ago. We got a new Board member and he did interviews, on energy savings, and this project was pushed thru. My direct boss still hasn't come thru on T & B. I was able to get Fire alarm technician in to redo controls and we tested the operation. If they cook at an odd time, the Hoods starters ping the T7300, thru a timed relay, and this runs the MAU(s) for 3 hours at a time.
    Last edited by madhat; 08-01-2010 at 02:30 PM.

  4. #4
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    Jul 2009
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    All that is left is running the application and checking thru the period to see how it works.Good luck.

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