12a30 System Sequence Logic

12.A3.1 SYSTEM MODE: Install capability for the user to easily and conveniently set and vary annual beginning and ending dates for the heating season to prevent simultaneous heating and cooling. Heating equipment operation will be determined by the time of year (i.e. space heating boilers and circulators will only operate during the heating season And be locked out during the rest of the year regardless of outside air temperature). Install October 15th to May 15th as initial parameters for the heating season. Heating season System Mode = 0, non-heating season System Mode = 1.

12.A3.2 SUMMER/WINTER: Install user adjustable variables for heating and cooling operations during building occupancy as follows:

a. Whenever System Mode = 0 and the outside air temperature is less than or equal to the user variable Winter Occupancy Setpoint (i.e. 65°F), summer/winter shall go to winter. If the outside air temperature is greater than the Winter Occupancy Setpoint and the highest occupied space temperature + greater than some user variable setpoint (i.e. 74°F) and Chiller Plant Operation is Enabled/on then summer/winter shall go to summer to allow the chillers to function. If the outside air temperature is greater than the Winter Occupancy Setpoint and Chiller Plant Operation is Disable/off, summer/winter shall remain in winter to allow maximum ventilation with outside air.

b. Whenever System Mode = 1 and the outside air temperature is greater than or equal to the user variable

Summer Occupancy Setpoint (i.e. 60°F), summer/winter mode shall go to summer to allow the chillers to function. If the outside air temperature is less than the Summer Occupancy Setpoint and the lowest occupied space temperature is greater than some user variable setpoint (i.e. 72°F) and is disabled/off, summer/winter mode shall go to winter to allow maximum ventilation with outside air. If the outside air temperature is less than the Summer Occupancy Setpoint and Chiller Plant Operation is Enabled/on, summer/winter mode shall remain in summer mode.

12.A3.3 OPTIMUM START: Install an adaptable optimum start of all control points for both heating and cooling functions as follows:

a. During optimum start for both heating and cooling, outside air dampers shall go fully closed; and, classroom and return air dampers shall go fully open; and, all exhaust fans shall be Disabled/off.

b. Optimum start shall be limited to a maximum number of hours and be user adjustable.

12.A3.4 CHILLER PLANT OPERATION: Install capability for the user to easily and conveniently set and vary annual beginning and ending dates for operation of the chiller plant. Install May 1 to November 10 as initial parameters for Chiller Plant Operation.

12.A3.5 DESIGNATED SPACE TEMPERATURE SETPOINTS: Install user variable space temperature setpoints as follows:

a. The occupied setpoint for all Classrooms, all Offices, the Media Center, the Music Area, the Cafeteria and Kitchen, The Industrial Arts Area, and the Auditorium shall be 72°F for both heating and cooling functions.

b. The occupied setpoint for the Locker Rooms shall be 74°F for both heating and cooling functions.

c. The occupied setpoint for the Main Gymnasium and the Auxiliary Gymnasium shall be 68°F for heating and 74°F for cooling.

d. The unoccupied heating Setback Temperature shall be 55°F.

e. The unoccupied cooling Setup Temperature shall be 80°F.

12.A3.6 FREE COOLING: Install free cooling into all algorithms that control air handling unit fans, attic exhaust fans, outside air dampers, return air dampers and space terminal unit dampers as follows:

a. Free cooling shall be Enabled/on to ventilate the building during unoccupied periods whenever the outside air temperature is greater than the user variable Free Cool Minimum (i.e. 45°F) and the enthalpy of the outside air is less than the enthalpy of the inside air and the average building temperature is greater than the user variable Free Cool Setpoint (i.e. 72°F).

b. Whenever free cooling is Enabled/on all outside air dampers, return air dampers and space terminal unit dampers shall go to the fully open position; and, all air handling units and attic exhaust fans shall be Enabled/on; and, the chiller plant and boiler plant shall be Disabled/off locked out.

12.A3.7 MINIMUM ON/OFF: Install a user adjustable Minimum On/Off time period (i.e. 5 minutes) in the control program for each piece of mechanical equipment.

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