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.