A. Base Bid: 1. Heating Contractor provide: a. Control sequences for HVAC systems, subsystems, and equipment.

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1 SECTION SEQUENCE OF OPERATIONS FOR HVAC CONTROLS PART 1 - GENERAL 1 WORK INCLUDES A. Base Bid: Heating Contractor provide: Control sequences for HVAC systems, subsystems, and equipment. B. Alternate Bid: None. 2 RELATED WORK A. Related Sections include the following: Section "Instrumentation and Control for HVAC" for control equipment and devices and for submittal requirements. 3 DEFINITIONS A. DDC: Direct digital control. B. VAV: Variable air volume. C. ADJ: Adjustable at operator workstation. 4 HEATING CONTROL SEQUENCES A. Heating-Water Supply Temperature Control: Input Devices: Temperature sensors. Output Devices: Control relays. Action: Stage boilers to maintain heating water supply temperature. 4. Display: Heating-water supply temperature. Heating-water supply temperature set point. Boilers activated. d. Boilers firing percentage. B. Heating-Water Supply Temperature Reset: Input Device: Outdoor-air sensor. Output Device: DDC system software. SEQUENCE OF OPERATIONS FOR HVAC CONTROLS

2 Action: Reset heating-water supply temperature in straight-line relationship with outdoor-air temperature for the following conditions: 160 deg F heating water when outdoor-air temperature is 0 deg F. 100 deg F heating water when outdoor-air temperature is 60 deg F. 4. Display: Outdoor-air temperature. Heating-water supply temperature. Heating-water supply temperature set point. C, Control Heating Circulating Pumps: 2, Input Devices: DDC system and differential pressure switches. Output Device: DDC system command to starter relays. Actions: Secondary hot water pumps shall run continuously. Primary hot water pumps shall be cycled with their associated boilers. On failure of lead secondary water pump, back-up pump shall start automatically. Control pump speed to maintain differential pressure set point Display: Pump command signal, Operating status of circulating pump(s). Pump failure alert, d. e. Pump speed. Differential pressure setpoint. f. Differential pressure. 5 CHILLER PLANT SEQUENCES A. Chillers WC-1 and WC-2 shall be controlled by factory mounted controls provided with Bacnet interface. B. Chiller controls shall perform the following functions: Start/stop chilled water pumps. Verify chilled water flow. Monitor chilled water supply temperature. 4. Monitor chilled water return temperature. 5. Control capacity. C. Building DDC control system shall monitor the following points and provide the following alarms to the operator workstation: Chilled water pumps proof of operation. Primary chilled water return temperature. Primary chilled water supply temperature. 4. Chiller start/stop. D. Building DDC control system shall stage chillers as follows: ,08 SEQUENCE OF OPERATIONS FORHVAC CONTROLS

3 2, Enable chiller(s) during occupied period as input at operator workstation. Enable chiller(s) when any secondary chilled water pump is started. Enable next stage chiller when water flow thru primary chilled water bypass flow meter drops below 20 gpm (adj). E. Building DDC control system shall control secondary chilled water pumps as follows: Start lead pump when any temperature in any space served by the pump exceeds its setpoint by more than 2 deg F (adj) for more than 30 minutes (adj). If lead pump does not prove flow, shut down the lead pump and start stand-by pump. Control pump speed to maintain differential pressure setpoint. 4. Provide differential pressure flow switch at each pump. F. Building DDC control system shall provide Bacnet connection points for WC-1 and WC- G. Display: Chiller command signal. Chiller status. Pumps commands signal. d. Pump status. e. Primary chilled water supply temperature. f. Primary chilled water return temperature. g- Secondary chilled water return temperature. 6 AIR-HANDLING-UNIT CONTROL SEQUENCES A. Start and Stop Supply Fan(s): Enable: Freeze Protection: Input Device: Duct-mounted averaging element thermostat, located before supply fan. Output Device: Hard wired through motor starter; DDC system alarm. Action: Allow start if duct temperature is above 37 deg F (3 deg C); signal alarm if fan fails to start as commanded. Initiate: Occupied Time Schedule: Input Device: DDC system time schedule. Output Device: Binary output to motor starter. Action: Energize fan(s). Initiate: Unoccupied Time Schedule: Input Device: DDC system based on space sensor beyond heating or cooling setpoint. Output Device: Binary output to motor starter. Action: Energize fan(s). 4. Unoccupied Ventilation: SEQUENCE OF OPERATIONS FOR HVAC CONTROLS

4 Input Device: DDC system time schedule and output. Output Device: DDC system binary output to motor starter. Action: Cycle fan(s) during unoccupied periods. 5. Display: Supply-fan on-off indication. Supply fan on-off command. B. Supply F an(s) V ariable-v olume Control: Occupied Time Schedule: Input Device: DDC system time schedule. Output Device: Binary output. Action: Enable control. Volume Control: Input Device: Static-pressure transmitter sensing supply-duct static pressure referenced to conditioned-space static pressure. Output Device: DDC system analog output to motor speed controller. Set variable-speed drive to minimum speed when fan is stopped. Action: Maintain constant supply-duct static pressure. High Pressure: Input Device: Static-pressure transmitter sensing supply-duct static pressure referenced to static pressure outside the duct. Output Device: DDC system binary output to motor starter. Action: Stop fan and signal alarm when static pressure rises above excessivestatic-pressure set point. 4. Display: C. Preheat Coil: Supply-fan-discharge static-pressure indication. Supply-fan-discharge static-pressure set point. Supply-fan speed. d. High pressure alarm. Supply-Air T emperature: Input Device: DDC system time schedule and electronic temperature sensor. Output Device: Modulating 3 way control valve. Valve to fail open to coil. Action: Maintain air temperature set point of 55 deg F (adj), 2, Display: Preheat-coil air-temperature indication. Preheat-coil air-temperature set point, SEQUENCE OF OPERATIONS FOR HVAC CONTROLS

5 Preheat-coil control-valve position. D. Mixed-Air Control: Occupied Time Schedule: Input Device: DDC system time schedule. Output Device: DDC system output. Action: Enable control. Minimum Position: Input Device: DDC system time schedule. Output Device: DDC system analog output to modulating damper actuator(s). Action: Open outdoor-air dampers to minimum position. Heating Reset: Input Device: DDC system software. Output Device: DDC system analog output to modulating damper actuator(s). Action: Set outdoor-air dampers to minimum position. 4. Supply-Air Temperature: Input Device: Duct-mounted electronic temperature sensor. Output Device: DDC system analog output to modulating damper actuator(s). Action: Modulate outdoor-, return-, and relief-air dampers to maintain air temperature set point of 55 deg F (adj). 5. Cooling Reset: Input Device: Outdoor- and return-air, duct-mounted electronic temperature sensors. Output Device: DDC system analog output to damper actuator(s). Action: Set outdoor-air dampers to minimum position when outdoor-air temperature exceeds return-air temperature (adj). 6. Unoccupied Time Schedule: Input Device: DDC system time schedule. Output Device: DDC system analog output to modulating damper actuator(s). Action: Position outdoor- and relief-air dampers closed and return-air dampers open. 7. Display: E. Filters: Mixed-air-temperature indication. Mixed-air-temperature set point. Outside and return air damper positions. SEQUENCE OF OPERATIONS FOR HVAC CON TROLS

6 Occupied Time Schedule: Input Device: DDC system time schedule. Output Device: DDC system output. Action: Enable control. Differential Pressure: Input Device: Differential-pressure switches. Output Device: DDC system alarm. Action: Signal alarm on high-pressure conditions. Display: Filter air-pressure-drop indication. Filter high-air-pressure set point. F. Hydronic or DX Cooling Coil: Occupied Time Schedule: Input Device: DDC system time schedule. Output Device: Binary output. Action: Enable control. Supply Ah - Temperature: Input Device: Duct-mounted electronic temperature sensor. Output Device: Normally closed modulating control valve (or cooling stages and hot gas bypass DX). Action: Maintain supply-air temperature set point of 55 deg F (adj). Unoccupied Time Schedule: Input Device: DDC system time schedule. Output Device: Binary output. Action: Disable control. 4. Display: Supply coil air-temperature indication. Supply coil air-temperature set point. Cooling-coil control-valve position (DX cooling stages activated, hot gas bypass status). G. Coordination of Air-Handling Unit Sequences: Ensure that preheat, mixed-air, heating-coil, and cooling-coil controls have common inputs and do not overlap in function. H. Operator Station Display: Indicate the following on operator workstation display terminal: DDC system graphi DDC system on-off indication. DDC system occupied/unoccupied mode. SEQUENCE OF OPERATIONS FOR IIVAC CONTROLS

7 Outdoor-air-temperature indication. Supply-fan on-off indication. Supply-fan-discharge static-pressure indication. Supply-fan-discharge static-pressure set point. Supply-fan speed. Preheat-coil control-valve position. Mixed-air-temperature indication. Mixed-air-temperature set point. Mixed-air damper positions. Filter air-pressure-drop indication. Filter high-air-pressure set point. Supply air-temperature indication. Supply air-temperature set point. Cooling-coil control-valve position (DX cooling stages activated). 7 CONSTANT VOLUME ROOFTOP UNITS A. Cycle cooling and heating stages as required to maintain space temperatures similar to air handling units. Provide dry bulb economizer controls similar to air handling units. B. The following units shall have C02 sensors located in the return air stream to modulate the outside air dampers to maintain maximum of 900 ppm of C02 in their associated space. RT- RT- RT- 4. RT RT VARIABLE VOLUME ROOFTOP UNITS. A. Cycle cooling and heating stages as required to maintain 55 degree discharge air temperatures similar to air handling units. Provide dry bulb economizer controls similar to air handling units. Provide variable compressor capacity or hot gas bypass cooling capacity control. B. Provide control of VSD supply fans based on duct static pressues. 9 TERMINAL UNIT OPERATING SEQUENCE A. Cabinet Unit Heater, Hydronic: Room Temperature: Input Device: Electronic temperature sensor. Output Device: DDC system binary output to fan motor and two way valve. Action: Open valve and cycle fan to maintain temperature. Low-Temperature Safety: Input Device: Line-voltage, on-off thermostat, pipe mounted. SEQUENCE OF OPERATIONS FOR HVAC CONTROLS

8 Output Device: Hard wired. Action: Stop fan when return heating-water temperature falls below 40 deg F. Display: Room temperature indication. Room temperature set point. Fan command. d. Fan status. B. Unit Heater, Hydronic: Room Temperature: Input Device: Electronic temperature sensor. Output Device: DDC system binary output to fan motor and two way valve. Action: Open valve and cycle fan to maintain temperature. Low-Temperature Safety: Input Device: Line-voltage, on-off thermostat, pipe mounted. Output Device: Hard wired. Action: Stop fan when return heating-water temperature falls below 35 degf (2 deg C). Display: Room temperature indication. Room temperature set point. Fan command. d. Fan status. C. VAV, Terminal Air Units with Hydronic Coils: Occupancy: Input Device: Occupancy sensor integral to temperature sensors. Output Device: DDC system binary output. Action: Report occupancy and enable occupied temperature set point. 1) Occupied Temperature: 74 deg F (cooling); 71 deg F (heating). 2) Unoccupied Temperature: 80 deg F (cooling); 60 deg F (heating). Room Temperature: Input Device: Electronic temperature sensor with integral occupancy sensor. Output Device: Electronic damper actuators and control-valve operators. Action: Modulate damper and valve to maintain temperature. 1) Sequence damper from full open to minimum position, then valve from closed to fully open. SEQUENCE OF OPERATIONS FOR HVAC CONTROLS

9 2) Minimum airflow shall be 0 cfm in unoccupied mode; value scheduled in occupied mode. 3) Reheat shall be disabled in unoccupied cooling mode. Fan powered VAV terminals for gym lobby shall operate after above in occupied mode. In unoccupied mode sensor shall activate parallel fan and open valve to heating coil on drop below setpoint. Provide low temperature alarm protection similar to 9.A.2 above. 4. Display: Room/area served, Room occupied/unoccupied. Room temperature indication, d. e. Room temperature set point, occupied (heating and cooling). Room temperature set point, unoccupied (heating and cooling). f. Air-damper position as percent open. g. Control-valve position as percent open. D. Natural Gas Unit Heater: Room temperature: Input Device: Electronic temperature sensor. Output Device: DDC digital output to heater controls. Action: Cycle heater to maintain temperature setpoint. Display: Room temperature indication. Room temperature setpoint. Heater status. d. Heater command. L10 VENTILATION SEQUENCES A. Exhaust Fan: Time schedule: Provide current sensing status relays for control and status of fans scheduled for BAS time scheduling. B. Mechanical Room Exhaust Fan: Fan shall operate at low speed continuously unless in alarm mode. Provide current sensing relays for control and status. Refrigerant leak detector shall provide digital output to DDC system to operate fan at high speed and provide alarm to DDC control system. C. Auto Shop Exhaust Fan: Provide current sensing status relays for time schedule control and status alarm. Provide gasoline vapor sensor to start fan during unoccupied periods. SEQUENCE OF OPERATIONS FOR HVAC CONTROLS

10 D. Temperature Control Exhaust Fans: Provide space temperature sensor to cycle fan motor to maintain cooling setpoint. See Schedule. 11 A. TEMPERATURE ALARMS Provide temperature sensor in dimmer room to sound alarm at workstation and dial out an alarm when temperature exceeds 80 degrees F. PART 2 - PRODUCTS (Not Applicable) PART 3 - EXECUTION (Not Applicable) END OF SECTION SEQUENCE OF OPERATIONS FOR HVAC CONTROLS