SECTION 15910 SEQUENCE OF OPERATION FOR HVAC CONTROLS PART 1 GENERAL 1.1 RELATED DOCUMENTS A. Drawings and general provisions of the Contract, including General and Supplementary Conditions and other Division 1 Specification Sections, apply to this Section. PART 2 PRODUCTS N/A PART 3 EXECUTION 3.1 SEQUENCE OF OPERATION A. BOILER CONTROL 1. The boiler control panel and associated wiring shall be furnished and installed by the boiler manufacturer. Boiler manufacturer to provide PIC statement along with BACnet MSTP interface to so that the BAS and the boiler control panel can communicate. 2. The BAS contractor shall furnish controls for variable flow hot water pumps including the isolation valves. Isolation valves shall be controlled by the boiler control panel provided by the boiler manufacturer. B. BOILER AND PUMP CONTROL 1. Boilers shall be enabled based upon an occupancy schedule. When there is a call for heating the lead hot water pump shall start and status shall be proven thru a current sensing relay. If the lead pump fails the lag pump shall start and alarm shall be generated thru the BAS. 2. The hot water pumps shall be modulated to by two (2) differential pressure sensors located 2/3 down the longest pipe at two (2) different locations. Project Points Ai== Analog In-----------------Outdoor Air Temperature Bi== Binary In------------------Lead Pump Status Bo==Binary Out----------------Lead Pump Start/Stop Ao==Analog Out---------------Lead Pump Speed Bi== Binary In------------------Lead Pump Alarm Bi== Binary In------------------Lag Pump Status Bo==Binary Out----------------Lag Pump Start/Stop Ao==Analog Out---------------Lag Pump Speed Bi== Binary In------------------Lag Pump Alarm Bo==Binary Out----------------Boiler Enable/Disable Ai== Analog In-----------------Hot Water Common Supply Water Temperature Ai== Analog In-----------------Hot Water Common Return Water Temperature C. VAV AHU with DX Coil (Typical of 2) 1. The heating and ventilation systems shall consist of variable volume air handling units. The air hanlding unit shall have Economizer dampers (outdoor air return air exhaust air), Supply fan, Return Fan, DX-Coil, Hot Water Coil and associated controllers sensors for maintaining a constant supply air temperature (55 F -60 F) which will be Proj, No. 11075 Sequence of Operation 15910-1
reset based on outdoor air. The economizer dampers shall be furnished with the air handler. VAV AHU Control a. The system operates as follows (All suggested set points and settings are adjustable) b. Johnson Controls shall furnish and install a digital controller for operation of the Variable Volume Air Handling Unit. All units shall operate based upon a schedule. c. Upon initial start-up the Variable Volume Unit/s shall operate as follows: The supply air fan and return air fan shall start with the outdoor air damper closed, return air damper open, exhaust air damper closed. Upon stabilization of system control processes, the system shall revert to total system operations as noted below. The DX-coil and hot water coil will be modulated/stage as necessary to maintain the discharge air setpoint. The outdoor air damper shall be set to a minimum position as determined by the outdoor airflow measuring station. The outdoor air damper shall be modulated from the minimum air position to 100% as the return air duct mounted CO2 increased above 700ppm over the current outdoor CO2ppm to utilize demand control ventilation. Air volume shall be controlled by modulating a VFD in response to static pressure sensors (2) mounted 2/3 downstream of the supply fan discharge. Duct static pressure shall be maintained at 1 W.G. The supply fan and return fan shall track together. The reheat coils will add reheat to the system to maintain room temperature. If the return air humidity is above 60 %( adj) the unit shall be force into cooling mode and the reheats will temper the air until the return humidity is at its desired setpoint. Fan shall shutdown if the following occur: High static pressure in the supply fan discharge. Low Static pressure in the return fan discharge. Smoke is detected by smoke detectors in the supply fan discharge and/or the return air. d. Each limit shall be a manual reset device. Smoke detectors (furnished and installed by the electrical contractor) shall be tied to the building fire alarm system to report a smoke condition that may exist. All limit alarms shall report to the facilities automation system. Project Points Bo== Binary Out -------Supply Air Fan Start/Stop Bi == Binary In ----------Supply Air Fan Status Bi == Binary In ----------Supply Air Fan High Static Alarm Ao==Analog Out--------Supply Air Fan Speed Bo== Binary Out -------Return Air Fan Start/Stop Bi == Binary In ----------Return Air Fan Status Bi == Binary In ----------Return Air Fan High Static Alarm Ao==Analog Out--------Return Air Fan Speed Ao==Analog Out -----Outdoor Air, Return Air & Exhaust Air Damper Control Ai == Analog In -------Mixed Air Temperature Proj, No. 11075 Sequence of Operation 15910-2
Bi == Binary In ----------Filter Status (Runtime) Ao ==Analog Out-------Hot Water Valve Bo ==Binary Out--------1 st Stage of Cooling Bo ==Binary Out--------2 nd Stage of Cooling Ai == Analog In -------Discharge Air Temperature Ai == Analog In -------Temperature Discharge Air Sensors Ai == Analog In -------Duct Static Sensors (2 required mount 2/3 downstream) Bi == Binary In ----------Supply Air Smoke Detector Alarm Bi == Binary In ----------Return Air Smoke Detector Alarm Ai == Analog In ---- --Temperature Return Air Sensor D. VARIABLE VOLUME BOXES with HOT WATER REHEAT 1. Johnson Controls shall furnish (for installation at the factory of the variable volume box manufacturer) a digital controller for operation of the Variable Volume Electric Reheat boxes. Variable volume controller shall include an integral damper operator/differential pressure sensor. The controller shall modulate the volume damper and stage the reheat coil to maintain the space temperature in response to a room temperature sensor. 2. A discharge air temperature sensor shall limit the supply air temperature to the room by overriding the control of the reheat coil. Supply air volume to the variable volume box shall be measured via the differential pressure sensor and flow ring (furnished by the box manufacturer). Combined they shall maintain the airflow rates between the minimum and maximum rates required for room control. 3. The room sensor shall have an integral plug for connection by the balancing contractor for setting the required airflow rates as defined by the specifications for each variable volume box. Once the balancing contractor has set the flows, the information may be uploaded to the central METASYS controller from the balancing contractor laptop to define final system operating parameters. 4. Electrical contractor shall provide 120vac power wiring to an area. 5. Johnson Controls shall furnish to the box manufacturer (for mounting and wiring) a VMA controller for each variable volume box. The variable volume box manufacturer shall install the VMA controller. 6. The variable volume box manufacturer shall furnish and connect the VMA controller to the following: Airflow ring for CFM volume control. 7. The variable volume box manufacturer shall provide this cost for this work. Project Points Ai == Analog In ---- Room Temperature Ai == Analog In -----Heating Coil Discharge Air Temperature Ai == Analog In ---- Variable Volume Box Airflow Ao == Analog Out --Heating Coil Control Ao == Analog Out -- Variable Volume Damper Control F. ENERGY RECOVERY UNIT 1. This unit is a constant volume unit and consists of a one (1) supply fan, one (1) exhaust fans, hot water coil, DX-Coil and a plate and frame exchanger. 2. The system operates as follows (All suggested set points and settings are adjustable) 3. Johnson Controls shall furnish and install a digital controller for operation of the Constant Volume Air Handler Unit. 4. Upon initial start-up the Constant Volume Unit/s shall operate as follows: The outdoor and exhaust air dampers shall open. Once status has been proven the supply fans and exhaust fans shall start. Proj, No. 11075 Sequence of Operation 15910-3
The hot water valve shall be modulated to maintain a discharge air setpoint of 70 (adj) degrees during the occupied mode. When the outdoor air is above 70 degrees the gas heat shall be off and the DX-Coil will be staged to maintain neutral air. When the unit is the unoccupied mode the unit shall be off. Fan shall shutdown if the following occur: Smoke is detected by smoke detectors in the supply fan discharge and/or the exhaust air. Each limit shall be a manual reset device. All limit alarms shall report to the facilities automation system. Project Points for Sections Bo==Binary Out------Supply Air Fan Start/Stop Bi== Binary In---------Supply Air Fan Status Bo==Binary Out------Exhaust Air Fan Start/Stop Bi== Binary In---------Exhaust Air Fan Status Bo==Binary Out--- -Outdoor/Exhaust Air Damper Bi ==Binary In---------Outdoor Air Damper Status Bi ==Binary In---------Exhaust Air Damper Status Bi ==Binary In --------Filter Status (Run Time Only) Ai ==Analog In ------Discharge Air Temperature Ao==Analog Out-----Gas Heat Modulation Bo==Binary Out------Stage 1 Cooling Bo==Binary Out------Stage 2 Cooling G. Cabinet Unit Heaters 1. An electric thermostat shall open the two way hot water valve and cycle the fan to maintain space temperature. A strap-on aqua stat shall be provided to prevent the operation of the unit fan unless hot water is available. All control devices shall be furnished and installed by the automatic temperature control manufacturer. All 120 Volt control interlock wiring shall be provided by this contractor. 2. Power wiring shall be by the electrical contractor. H. General Exhaust Fan Operation - Monitoring 1. General exhaust fans shall be start-stopped and monitored for system operation and/or alarm. Refer to drawings for fans requiring operation/monitoring. GENERAL EXHAUST FAN MONITORING: Bo==Binary Out -------Exhaust Fan Start/Stop Bi == Binary In ---------Exhaust Air Fan Alarm/fault I. Stand Alone Split Systems 1. The BAS contractor shall furnish and install a space sensor in the IT room and elevator equipment room to monitor the space temperatures and alarm the BAS on a rise in temperature. 2. Equipment manufacturer shall provide remote thermostat for ATC to install. 3. ATC to provide low voltage interlock wiring to remote condensing unit. J. Radiant Panels 1. An electronic DDC thermostat shall modulate a two-way control valve to maintain space temperature. This DDC thermostat shall be networked to the Metasys building automation system. 2. During the "Unoccupied" cycle the DDC thermostat shall maintain an unoccupied space temperature. 3. Where radiant panels are sequenced with other devices (i.e. duct mounted reheat coils), the radiation control valve shall be sequenced to be the first control valve to open on a call for heat and the last to close on a call for ventilation / cooling is required. K. Fan Coil Units Proj, No. 11075 Sequence of Operation 15910-4
1. Fan coil units shall be controlled by an electronic DDC thermostat. This DDC thermostat shall be networked to the Metasys building automation system. 2. During the occupied mode, the unit fan shall run continuously with the unit coil valve modulated by the DDC thermostat to maintain room setting. 3. During the un-occupied mode, the unit fan shall run cycle by the DDC thermostat to maintain a reduced room temperature setting. At this time the unit coil valve shall be fully open. 4. Furnish 2-position outdoor air dampers for units where shown on the plans and noted in the unit schedule. Damper shall open during the occupied cycle and shall remain closed during the un-occupied cycle. 5. Damper shall be furnished by the controls contractor with the installation by the HVAC sheet metal contractor. Refer to the plans for specific locations and damper sizes. L. SYSTEM LIMIT DEVICE MONITORING 1. LIMIT DEVICES for SYSTEM FANS All system fans (Air Handlers, Exhaust Fans, and Make-up Air Fans) shall be provided with various limits for fan shutdown. All limit devices shall be hardwired to accomplish fan system shutdown. Limit devices shall also have a system operational priority to accomplish system shutdown. 2. FIRE ALARM SYSTEM LIMIT DEVICES Duct Smoke Detectors Duct Smoke Detectors shall be furnished by the electrical contractor. Refer to plans (HVAC and electrical) for locations. HVAC contractor shall mount the duct detectors as noted on the plans. The fire alarm system shall stop the fan system (supply fans and return fans) upon receipt of a detection of smoke from duct smoke detectors and/or area smoke detectors. Fan system shall be stopped via a fire alarm addressable control module that is networked into the building fire alarm system. The fire alarm addressable control module/s shall be furnished by the electrical contractor (fire alarm system supplier). The electrical contractor shall mount the fire alarm addressable control module/s at the fan system VFD drive or starter. 3. TEMPERATURE CONTROL LIMIT DEVICES a. Low Temperature Thermostats Binary (Bi) Input Low Temperature (manual reset) thermostats shall be furnished and installed by the BAS control contractor. Thermostats shall be installed for each 20 sq ft of coil area and have a range from 35 to 45. b. Static Pressure Switches - Binary (Bi) Input (Low pressure and High pressure) Static switches shall be used for fan system shutdown operations based upon high and/or low static pressure. Static pressure switches shall be manual reset devices. Static pressure limit switches shall be hard wired to stop the fan system if device high or low static pressure limit is exceeded. Static pressure switch settings shall be set during fan testing with the Air balancing contractor and confirmed with the Commissioning Agent. Each static pressure switch range shall be selected for the operating static pressures required for the associated fan systems. All static pressure switch limit ranges shall be approved by the engineer. c. Static Pressure Sensors -- Analog (Ai) Input (Low pressure, Differential pressure across Fan/s and High pressure) Proj, No. 11075 Sequence of Operation 15910-5
Static sensors shall be used for automatic operations of the fan speed based upon high static, static differential across each fan set/s and/or low static pressure. Differential static pressure sensors across each fan system set shall be bi-directional. Static sensor shall read both positive and/or negative differential across each fan system set. High positive differential and/or low negative differential may be set in software for fan override operation and/or fan shutdown. Settings shall be different for fan control and fan shutdown. Static pressure sensor static limits shall be set in software to stop the fan system based on software limits during fan testing with the Air balancing contractor and confirmed with the Commissioning Agent. Each static sensor range shall be selected for the operating static pressures required for the fans and duct static pressure operation. All static pressure sensor ranges shall be approved by the engineer. d. Safety Limits All safety limits shall be manual reset type and shall be hard wired thru the local BACnet panel to the Air Handling Unit VFD drives to provide shutdown of the fan systems. This shall include the following limits and damper position end switches. Return air duct smoke detector. Low static pressure in the return plenum (inlet to return fans). High differential static pressure across the return fans. Low static pressure in the return-exhaust air plenum (outlet from the return fans). Low temperature thermostats (6 required 1 per 15 sq ft coil area). Low static pressure in the supply fans inlet plenum (inlet to supply fans). High differential static pressure across the supply fans. Low static pressure in the supply fans outlet plenum (outlet from the supply fans). Supply air duct smoke detector. e. Safety limits shall be hardwired thru the local BACnet panel to the Air Handling Unit VFD drives to command the fan system OFF upon receipt of a limit in an alarm condition. f. All limit devices (low temperature, high or low static, smoke detectors) are manual reset devices requiring each device (alarm) to be acknowledged at the device (system limit alarm verified and corrected). Clearing the device (resetting the specific limit) will not automatically restart the fan system. g. The system can only be restarted based upon an operator acknowledgement at the BMS system for the device in alarm and then initiating a manual restart command at the BMS system. END OF SECTION Proj, No. 11075 Sequence of Operation 15910-6