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15 AIR COOLED CHILLER CHILLED WATER PUMP CONTROL: The chilled water pump with the lowest runtime will automatically start when the outside air temperature rises above the system enable setpoint. When the outside air temperature falls below this setpoint, the chilled water pumps will turn off. When enabled, the lead pump will start and run continuously. If for any reason its status does not match its commanded value an alarm will be generated. The lag pump will start if the lead pump is in alarm. Differential pressure controller shall control pump VFD by monitoring flow and pump RPM. CHILLER CONTROL: The chiller will be enabled when the chilled water pump has a status of on. The chiller via its internal controls will maintain the chilled water supply temperature at setpoint. If the chilled water supply temperature rises above the high limit setpoint after operating for a period of time, an alarm will be generated. DEDICATED OUTSIDE AIR UNIT SUPPLY FAN START/STOP: The supply fan will be started according to the occupancy schedule. After the supply fan has been started after all safeties have been satisfied such as outside air damper limit switch, the control sequence will be enabled. Face/bypass will modulate between degrees F. ZONE CONTROL: The gas valve modulates, and the chilled water control valve will modulate/cycle in sequence to maintain the zone temperature at setpoint. HUMIDITY CONTROL COOLING MODE: Upon outside air dewpoint temperature reaching 55 degrees F or above, chilled water control valve shall modulate to maintain leaving air temperature of 55 degrees F DB, and the gas reheat control valve shall modulate to maintain discharge air temperature of 75 degrees F DB. NIGHT SETBACK: When in unoccupied mode, the unit outside air damper will close position. SHUTDOWN: When the unit is shutdown by either a stop command or system safety the unit will be set as follows: Supply fan will be off Chilled water valve will be close Gas heat will be off An alarm will be sent through the DDC for all system safety shutdown. AIR HANDLING UNIT AND FAN COIL UNITS SUPPLY FAN START/STOP: The supply fan will be started according to the occupancy schedule. Outside air damper will fully open to set position per indication by end switch on actuator. If the supply fan status does not match the commanded value, an alarm will be generated. When the supply fan status indicates the fan started, the control sequence will be enabled. Sequence exhaust and relief fans (new and existing) with AHU S. DISCHARGE AIR CONTROL: The discharge air temperature setpoint will reset as necessary to maintain the zone temperature setpoint as sensed by the discharge air temperature sensor. The mixed air dampers, and the cooling valve will modulate in sequence to maintain the discharge air temperature at setpoint. MIXED AIR LOW LIMIT OVERRIDE: The mixed air temperature will override the minimum position and close the outside air damper if a temperature is sensed below the setpoint. NIGHT SETBACK/NIGHT SETUP: When in unoccupied mode, the unit will cycle as necessary to maintain the night setback zone temperature at setpoint. Outside air damper will close position. Return air damper will fully open. A differential prevents the unit from cycling excessively. Fan and cooling valve will modulate to maintain unoccupied temperatures. SAFETY: All of the safety devices are manual reset; the device that has tripped must be manually reset before restarting the air handling unit. If a temperature low limit switch senses a temperature below setpoint the supply fan will be shutdown. If a fire alarm shutdown contact is provided, the supply fan will be shutdown when triggered. An alarm will be sent through the DDC for all system safety shutdown. SHUTDOWN: When the unit is shutdown by either a stop command or system safety the unit will be set as follows: Supply fan will be off Outside air damper will close Return air damper will open Cooling valve will close Electric heater will be off DEMAND CONTROL VENTILATION Only AHU 2,3,4 will utilize demand control ventilation. FAN COIL UNIT OCCUPIED MODE: During this mode the fan will run continuously. Outside air damper will fully open to set position per indication by end switch on actuator. When the room temperature is between the occupied heating and cooling setpoints (inside of the bias), the heating will be off, and the cooling valve will be closed. On a rise in room temperature above the cooling setpoint, the cooling valve will modulate open and the heating will remain off. On a drop in room temperature below the heating setpoint, the heating will cycle on and the cooling valve will remain closed. UNOCCUPIED MODE: During this mode the fan will cycle off. Outside air damper will go to the closed position. Return air damper will fully open. On a rise in room temperature above the unoccupied cooling setpoint, the fan will cycle on, the cooling valve will modulate open, and the heating will remain off. On a drop in room temperature below the unoccupied heating setpoint, the fan will cycle on, the heating will cycle on and the cooling valve will remain closed. EXISTING DX SPLIT SYSTEM SUPPLY FAN START/STOP: The supply fan will be started according to the occupancy schedule. If the supply fan status does not match the commanded value, an alarm will be generated. When the supply fan status indicates the fan started, the control sequence will be enabled. DISCHARGE AIR CONTROL: The discharge air temperature setpoint will reset as necessary to maintain the zone temperature setpoint as sensed by the zone temperature sensor. The heating control will energize and the DX cooling valve will modulate in sequence to maintain the discharge air temperature at setpoint. ECONOMIZER MODE: Upon outside air dry bulb temperature dropping below 55 degrees F and zone temperature control calling for cooling, outside air damper opens fully and return air damper shuts. Outside air damper and return air damper shall modulate to maintain designed leaving air temperature. Heating control will energize or DX cooling valve shall modulate to maintain zone relative humidity below 60% relative humidity based on outdoor air temperature. NIGHT SETBACK/NIGHT SETUP: When in unoccupied mode, the unit will cycle as necessary to maintain the night setback zone temperature at setpoint outside air damper shuts and return air damper opens fully. A differential prevents the unit from cycling excessively. SAFETY: All of the safety devices are manual reset; the device that has tripped must be manually reset before restarting the air handling unit. If a temperature low limit switch senses a temperature below setpoint the supply fan will be shutdown. If a fire alarm shutdown contact is provided, the supply fan will be shutdown when triggered. An alarm will be sent through the DDC for all system safety shut down. SHUTDOWN: When the unit is shutdown by either a stop command or system safety the unit will be set as follows: Supply fan will be off Outside air damper will close Return air damper will open DX cooling valve will close Heating will be off Compressor will be off EXISTING ROOF TOP UNIT SUPPLY FAN START/STOP: The supply fan will be started according to the occupancy schedule. After the supply fan has been started, the control sequence will be enabled. ZONE CONTROL: The gas valve modulates, and the dx cooling stages will modulate/cycle in sequence to maintain the zone temperature at setpoint. NIGHT SETBACK/NIGHT SETUP: When in unoccupied mode, the unit will cycle as necessary to maintain the night setback zone temperature at setpoint and outside air damper shuts and return air damper opens fully. A differential prevents the unit from cycling excessively. SHUTDOWN: When the unit is shutdown by either a stop command or system safety the unit will be set as follows: Supply fan will be off Dx cooling will be off Gas heat will be off An alarm will be sent through the DDC for all system safety shut down. ATFP EMERGENCY SHUT-OFF: DOAU, EXHAUST AND RELIEF DAMPERS: Activation of the ATFP emergency shut off switch will create a disabled signal. Outside air and exhaust and relief air dampers will immediately go to the closed position. All HVAC control commands will be over written by the ATFP emergency shut off switch disabled command. Once the ATFP emergency shut off switch has been cleared the HVAC system controller will return to the normal sequence of operation. OUTSIDE AIR RELIEF AND EXHAUST AIR DAMPER(S): Outside air damper shall have a maximum 3CFM/SF with a differential pressure of 1 of water column across the damper

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