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This document is protected by copyright and is the exclusive property of RenewAire, LLC. RenewAire authorizes the user to use this document or portions thereof for limited, non-exclusive purposes to prepare written product specifications for the CSI MasterFormat category above. All information contained herein provided by RenewAire, LLC is for informational purposes only and is furnished without representation or warranty of any kind, express or implied, regarding the user or any other party, including, without limitation, ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT. To the extent permitted by applicable law, RenewAire disclaims all liability, and the user assumes all responsibility and risk associated with the use of, or reliance on, this document or the information contained herein, whether modified by the user or not. Users should consult www.renewaire.com to verify that this document corresponds to the most recent version.

For RenewAire product data, including equipment description, catalog, and instruction manuals, visit www.renewaire.com/our-ervs/.

This product is available in several different configurations. The unit is typically installed as part of a building's HVAC system.

For questions regarding this product, please contact your local authorized RenewAire representative. To find your local representative, visit www.renewaire.com/how-to-buy/find-a-dealer/ and select your region.

SECTION 23 72 00 - AIR-AIR ENERGY RECOVERY VENTILATOR

PART 1 – GENERAL

1.1 SUMMARY

This section includes air-air energy recovery ventilators intended for rooftop installation. In this document, these units may be abbreviated as "energy recovery ventilator" (ERV) for brevity.

1.2 REFERENCES

Drawings and general contract provisions, including "General Requirements," "Division 01," "Division 23," and "Specifications," along with common HVAC requirements, apply to work specified herein. Section 23 09 00: Controls and Instrumentation.

1.3 DOCUMENTS TO BE FURNISHED

• Product Data: For each type or model of energy recovery ventilator, include the following information:
  • Unit performance data for supply and exhaust air, indicating system operating conditions.
  • Enthalpy core performance data for summer and winter operation.
  • Motor and unit electrical characteristics.
  • Dimensioned drawings for each installation type, with isometric and plan views, showing connected ductwork location and maintenance clearance requirements.
  • Estimated gross weight of each installed unit.
  • Filter types, quantities, and sizes.
  • Installation, Operation, and Maintenance (IOM) manual for each model.
• Documents for LEED Certification: Provide data for prerequisite E01: Documentation indicating units comply with ASHRAE 62.1-2010, Section 5 – Systems and Equipment.
• Execution Drawings: For air-air energy recovery ventilators, include plans, elevations, sections, details, and attachments related to other work. Detail equipment assemblies and indicate dimensions, weights, loads, required clearances, site assembly method, components, and location and size of each site connection.
• Wiring Diagrams: For power, signal, and control wiring.
• Operation and Maintenance Data: For the air-air energy recovery ventilator.

1.4 QUALITY ASSURANCE

• Source Limitations: Procure the air-air energy recovery ventilator with all associated components or accessories from a single manufacturer.
• Workmanship: For fabrication, installation, and actual testing of work covered herein, employ only fully trained and experienced workers who are thoroughly familiar with the required elements and installation methods currently recommended by the manufacturer.
• Warranty: The ERV core shall be warranted free from manufacturing defects and to retain its functional characteristics, under normal use conditions, for a period of ten (10) years from the date of purchase. The remainder of the unit shall be warranted free from manufacturing defects and to retain its functional characteristics, under normal use conditions, for a period of two (2) years from the date of installation.
• Manufacturer Testing: The manufacturer must provide proof of independent core testing by Underwriters Laboratory (UL) for flame spread index (FSI) max 25 and smoke developed index (SDI) max 50, meeting NFPA90A and NFPA90B. Test method per UL 723.
• Certifications:
  • Energy recovery cores used in these products shall be third-party certified in accordance with AHRI Standard 1060 for energy recovery ventilators. Certifications published by AHRI shall confirm manufacturer’s published performance data for airflow, static pressure, temperature, and total efficiency, purge airflow (OACF), and exhaust airflow leakage (EATR). Products not currently certified by AHRI will not be accepted. OACF shall not exceed 1.02, EATR shall be 0% of balanced airflow.
  • The unit assembly shall be listed per UL 1812 for ducted air-to-air heat exchangers and comply with CSA 22.2.
  • Units intended for outdoor use shall be rain tested in accordance with UL 1812, Section 67.
• Factory Testing: Each unit shall be factory tested prior to shipment: motor dielectric test on test bench, unit dielectric test, internal control circuit continuity test, unit amperage test.

1.5 COORDINATION

• Coordinate the size and location of all building penetrations required for the installation of each energy recovery ventilator and associated plumbing and electrical systems.
• Coordinate the sequencing of construction work for associated plumbing, HVAC, and electrical power.
• Coordinate the dimensions and location of roof curbs, equipment supports, and roof penetrations with the actual equipment furnished.

PART 2 – PRODUCTS

2.1 MANUFACTURERS

• Available Manufacturers: Subject to compliance with the specifications contained herein, manufacturers proposing products that can be integrated into the work include, but are not limited to:
  • RenewAire
• The manufacturer shall have been in business for at least 10 years in the manufacturing of energy recovery ventilators.

2.2 FABRICATED UNITS

Air-air energy recovery ventilators shall be fully factory assembled and consist of a fixed-plate, cross-flow heat exchanger with no moving parts, a 20-gauge insulated casing [single][double] [G90 galvanized][painted], an outdoor air hood with bird screen, a motorized outdoor air intake damper, filter assemblies for supply and exhaust air, an enthalpy core, a supply air fan assembly, a motorized exhaust air damper, an exhaust air hood, an exhaust fan assembly, and an electrical control box with all specified components and factory-installed internal accessories, tested and prepared for single-point high-voltage connection. The entire unit, except for site-installed components, shall be factory assembled and tested.

2.3 CABINET

• Materials: Single [double]-wall insulated metal cabinet fabricated to allow access to internal components for servicing.
• Exterior Casing: 20-gauge galvanized steel (G90) complying with ASTM A653 for components not receiving a painted finish. [Factory-provided painted components shall be coated with urethane polyester paint over 20-gauge G90 galvanized steel.]
• Access Doors: Shall be equipped with hinges and sealed closed-cell foam gaskets. Door pressure taps, with captive plugs, shall be provided for measuring transverse pressure, thereby accurately measuring airflow.
• Duct Connections: Unit shall be equipped with factory-installed duct flanges on all duct openings.
• Cabinet Insulation: Cabinet walls and doors shall be insulated with 1-inch thick, 4 lb density fiberglass insulation, faced with aluminum foil and facing, providing a cleanable surface and eliminating any risk of fresh air exposure to fiberglass, with a minimum R-value of 4.3 (hr-ft²-°F/BTU).
• Enthalpy Core: The energy recovery core shall be of the total enthalpy type, capable of transferring both sensible and latent energy between air streams. Latent energy transfer shall be accomplished by direct transfer of water vapor from one airstream to the other, without exposing the transfer medium in subsequent cycles directly to exhaust air then to fresh air. No condensate drain shall be permitted. The energy recovery core shall be designed and constructed to allow for cleaning and removal for servicing. The energy recovery core shall be warranted for ten years. Performance criteria shall comply with AHRI Standard 1060.
• Control Center / Connections: The energy recovery ventilator shall be equipped with an electrical control center where all high and low voltage connections are made. The control center shall be designed to allow for single-point high-voltage power connections to the disconnect device [non-fused][fused].
• Passive Freeze Protection: The ERV core shall operate without condensation or frosting under normal operating conditions (defined as outdoor temperatures above -10 °F and indoor relative humidity below 40%). Occasional extreme conditions shall not affect the core’s normal operation, performance, or durability. No condensate drain is permitted.
• Motorized Isolation Damper(s): Motorized dampers for exhaust and fresh air, of AMCA Class I type, shall be factory installed.

2.4 FAN SECTION

• Construction of Fan Section, Supply and Exhaust Air: Fan assemblies consist of a TEFC motor [208-230 V][460 V][575 V] three-phase 60 Hz and a direct-drive forward-curved impeller fan.
• Fan Assemblies: Shall be statically and dynamically balanced and designed to operate continuously at maximum fan speed and power.

2.5 MOTORS

Fan motors shall be high efficiency, EISA compliant, TEFC motors with factory-installed starters.

2.6 UNIT CONTROLS

• Fan Control: Integrated VFDs for both air streams.
• Bypass/Economizer Control: Enthalpy differential control, 2-position dampers for 100% airflow passing through the core or 100% airflow bypassing the core.
• Sensors: [None.][Clogged filter controller for both air streams.]
• Timer: Digital timer [wall mount][exterior mount, NEMA 3R enclosure], with up to 8 on/off cycles per day or 50 per week, 24 VAC power, with battery backup to protect program settings in case of power failure to power the unit.
• Occupancy Sensor: Passive infrared sensor for [wall][ceiling] mounting with adjustable shut-off delay up to 30 minutes, 24 VAC power to power the unit.
• Carbon Dioxide: Adjustable control from 600 to 2000 ppm for [wall][duct] mounting with digital display.
• Microprocessor Controller and Sensors: Factory installed, high-end ERV controls which:
  • Comply with Division 23 requirements, section "Sequence of Operations for HVAC Controls."
  • Provide factory-installed hardware and software to allow building automation interface via [Modbus][BACnet] to monitor, control, and display status and alarms.
  • The microprocessor controller shall be capable of operating at temperatures between -20 °F and 160 °F.
  • The microprocessor controller shall be DIN rail mount type.
  • The factory-installed microprocessor controller shall be equipped with a backlit LCD screen allowing menu display for unit navigation and control.
  • The microprocessor controller shall be capable of communicating with the building automation system via Modbus RTU/TCP and BACnet MSTP/IP.
  • The microprocessor controller shall provide an integrated Ethernet interface and web server for displaying unit parameters.
  • The microprocessor shall provide a near-field communication (NFC) function for Android devices.
  • The microprocessor controller shall provide an internal programmable clock that will allow the user to add different occupancy programs and holidays.
  • The microprocessor controller shall be capable of performing built-in diagnostics.
  • The microprocessor controller shall be capable of displaying units in IP or SI.
  • The microprocessor controller shall be equipped with a battery-powered clock.
  • The microprocessor controller shall provide at a minimum three modes of occupancy determination: a dry contact, the internal clock, or the building automation system (BMS).
  • A remote user terminal allowing remote monitoring and setpoint adjustment, thereby facilitating access to controls without having to go outside or into the mechanical room if the user desires.
  • The microprocessor controller shall provide a minimum of (10) universal inputs/outputs (AI, DI, AO) and (6) six relay outputs (DO).
  • The microprocessor controller shall provide an integrated field bus port.
  • The microprocessor controller shall allow for I/O expansion.
  • The microprocessor controller shall provide a micro USB port for loading application program, unit parameters, logging journals, etc.
• Required Sensors: The following sensors are required for control:
  • (2) Temperature sensor for fresh air and exhaust air.
  • (2) Temperature and humidity sensor for outdoor air and return air.
  • (2) Differential pressure sensors for filter alarms.
  • [(2) Differential pressure sensors to measure pressure drop across the energy recovery core and to determine airflow in both airstreams.]
  • (2) Adjustable current switches.
  • [IAQ sensor for duct or room, field installed.]
  • [CO2 sensor in duct or room, field installed.]
  • [Static pressure sensor for duct, field installed.]
  • [Room pressure sensor, field installed.]
• Alarm Monitoring: The microprocessor controller shall be capable of monitoring unit conditions to detect alarm situations. When an alarm is detected, the microprocessor controller shall be capable of logging the alarm description, time, date, available temperatures, and unit status for the user to review. A digital output shall be provided for remote alarm indication. Alarms shall also be communicated via the building automation system (BMS), if applicable. Provide the following alarm functions:
  • Outdoor air temperature sensor alarm.
  • Outdoor air humidity sensor alarm.
  • Return air temperature sensor alarm.
  • Return air humidity sensor alarm.
  • Fresh air sensor alarm.
  • Exhaust air sensor alarm.
  • Dirty filter alarm.
  • Supply and exhaust air control alarm.
  • [Outdoor air flow sensor alarm.]
  • [Exhaust air flow sensor alarm.]
  • [Duct static pressure sensor alarm.]
  • [Room pressure sensor alarm.]
  • [CO2 sensor alarm.]
  • [Total VOC sensor alarm.]
  • [Air flow out of range alarm.]
  • [Supply air temperature out of range alarm.]
  • [Supply air temperature low limit alarm.]
• Display Information: Display the following information on the microprocessor controller screen:
  • Unit running.
  • Unit economizer/bypass mode.
  • [Cooling status.]
  • [Heating status.]
  • Outdoor air temperature.
  • Outdoor air humidity.
  • Return air temperature.
  • Return air humidity.
  • Supply air temperature.
  • [Airflow in both airstreams.]
  • Unit on/off.
  • Fan on/off.
  • Damper status.
  • Digital alarm display.
• Sequences of Operation: The microprocessor controller shall have multiple factory pre-programmed sequences of operation for ERV control. Factory default settings shall be fully adjustable in the field. Factory pre-programmed sequences of operation available are as follows:

  SEQUENCE OF OPERATION

CONTROLLER DDC:

• Controller with integrated LCD screen for modifying setpoints and monitoring unit operation.
• Provided with necessary sensors and programming.
• Factory programmed, mounted, and tested.
• Integrated USB and Ethernet ports for program updates and journal file retrieval.

BMS INTERFACE:

• [BACnet MS/TP]
• [BACnet IP]
• [Modbus RTU]
• [Modbus TCP]

GENERAL OPERATION

POWER UP:

When the unit main circuit breaker is closed, a 10-second (adjustable) delay shall elapse before the controller comes online.

ERV UNIT START COMMAND:

An input signal is required to activate unit operation. The unit is started by:

• [Digital Input]
• [BMS Command]
• [Internal Clock]
• [Activation via Controller Screen]

All activated input types must be true before the unit will start.

• The exhaust fan starts after a 3-second (adjustable) delay. The exhaust fan shall not start until the damper actuator end-of-travel switch is closed.
• The supply fan starts after a 6-second (adjustable) delay. The supply fan shall not start until the damper actuator end-of-travel switch is closed.
• The supply fan, exhaust fan, economizer, [heating], and [cooling] shall be controlled based on selected unit operating modes and air conditions.

ERV UNIT SHUTDOWN COMMAND (OR POWER OFF):

• The unit may then be shut down by:
  • [Digital Input]
  • [BMS Command]
  • [Internal Clock]
  • [Deactivation via Controller Screen]
• The supply fan and exhaust fan shall be shut down.
• All dampers shall be de-energized and return to their default position after a 10-second (adjustable) delay.

SUPPLY FAN OPERATION:

• [The supply fan shall operate at a constant speed.]
• [The supply fan speed shall be controlled for:]
  • [Fixed percentage of maximum speed (0%-100%)]
  • [Supply airflow (CFM)]
  • [Supply duct static pressure]
  • [Ambient pressure]
  • [IAQ (TVOC)]
  • [CO2 fixed]
  • [CO2 airflow]
• The unit shall attempt to start the supply fan when the supply fan delay timer expires. When the supply fan starts, the supply fan adjustable current switch shall close and remain closed until the fan is stopped.

SUPPLY FAN STATUS:

Once the supply fan current switch is closed, [heating] [cooling] operation is permitted. After a 90-second (adjustable) delay from the supply fan start signal, if the supply fan current switch is still open, the supply fan alarm shall be activated and [heating], [cooling] operation shall be prohibited. Supply fan status shall only be active when the supply fan output is active and the supply fan current switch is closed. Supply fan status shall be inactive under all other circumstances.

FAN FIXED SPEED OPTION:

Analog voltage command to the supply fan VFD can be set from the unit controller screen [or provided by the BMS]. The adjustable range of 0% to 100% corresponds to the minimum and maximum fan speed. This supply fan operating mode can be used to balance supply airflow in the field.

SUPPLY AIRFLOW CONTROL OPTION:

The controller adjusts the supply fan VFD command to maintain the supply airflow at a setpoint. The supply airflow setpoint is entered and adjusted from the unit controller screen [or provided by the BMS]. Minimum and maximum values for the supply airflow setpoint are unit dependent. An adjustable PI (proportional and integral) loop compares the measured supply airflow to the airflow setpoint and adjusts fan speed. If the measured airflow varies by more than 10% (adjustable) from the desired airflow for more than 60 seconds (adjustable), a supply airflow alarm shall be triggered. This supply fan operating mode can be used to provide constant airflow when unit filters become loaded.

SUPPLY DUCT STATIC PRESSURE CONTROL OPTION:

The controller adjusts the supply fan frequency drive command to maintain the supply duct static pressure at a setpoint. The supply duct static pressure setpoint is entered and set from the unit controller screen [or provided by the BMS]. Minimum and maximum values for the supply duct static pressure setpoint are unit dependent. An adjustable PI (proportional and integral) loop compares the measured supply duct static pressure to the static pressure setpoint and adjusts fan speed. If the measured static pressure varies by more than 0.05 inches of water column (adjustable) for more than 60 seconds (adjustable) from the desired static pressure, a supply air static pressure alarm shall be activated. This supply fan operating mode can be used to provide constant duct static pressure for VAV systems.

ROOM STATIC PRESSURE CONTROL OPTION:

The controller adjusts the supply fan frequency drive command to maintain room static pressure at a setpoint. Room static pressure is typically measured as the differential pressure between the room and an adjacent space or the outside. The room static pressure setpoint is entered and set from the unit controller screen [or provided by the BMS]. An adjustable PI (proportional and integral) loop compares the measured room static pressure to the static pressure setpoint and adjusts supply fan speed. If the measured static pressure varies by more than 0.05 inches of water column (adjustable) for more than 60 seconds (adjustable) from the desired static pressure, a supply air static pressure alarm shall be triggered. This supply fan operating mode can be used to maintain constant room static pressure in a zone to control infiltration or exfiltration from an adjacent zone or the outside.

INDOOR AIR QUALITY (TVOC) CONTROL OPTION:

The controller adjusts the supply fan VFD command to maintain the ambient or return air TVOC level at a setpoint. The TVOC setpoint is entered and adjusted from the unit controller screen [or provided by the BMS]. An adjustable PI (proportional and integral) loop compares the measured TVOC level to the TVOC setpoint and adjusts fan speed. Minimum and maximum fan speed commands are adjustable. If the measured TVOC level exceeds 1000 ppm (CO(2) equivalent, adjustable) for more than 60 seconds (adjustable), a TVOC alarm shall be triggered. This supply fan operating mode can be used to provide demand-controlled ventilation for a space. Minimum fan speed shall provide the minimum required outdoor air when the TVOC level is at or below the TVOC setpoint.

CO2 CONTROL OPTION:

The controller adjusts the supply fan VFD command to maintain the room or return air CO2 level at a setpoint. The CO2 setpoint is entered and set from the unit controller screen [or provided by the BMS]. An adjustable PI (proportional and integral) loop compares the measured CO2 level to the CO2 setpoint and adjusts fan speed. Minimum and maximum fan speed commands are adjustable. If the measured CO(2) level exceeds 1000 ppm (adjustable) for more than 60 seconds (adjustable), a CO(2) alarm shall be triggered. This supply fan operating mode can be used to provide demand-controlled ventilation for a space. Minimum fan speed shall provide the minimum required outdoor air when the CO(2) level is at or below the CO(2) setpoint.

CO2 AIRFLOW CONTROL OPTION:

The controller adjusts the supply fan frequency drive command based on the measured room or return air CO2 level. The supply airflow setpoint is derived from the minimum and maximum CO2 levels and desired minimum and maximum airflow rates entered by the user. When the CO(2) level is at or below the minimum CO(2) level, the airflow setpoint is at minimum, and when the CO(2) level is at or above the maximum CO(2) level, the airflow setpoint is at maximum. Between the minimum and maximum CO(2) levels, the airflow setpoint is linearly proportional. If the measured CO(2) level exceeds 1000 ppm (adjustable) for more than 60 seconds (adjustable), a CO(2) alarm shall be triggered. This supply fan operating mode can be used to provide demand-controlled ventilation for a space. Minimum fan speed shall provide the minimum required outdoor air when the CO(2) level is at or below the CO(2) setpoint.

EXHAUST FAN OPERATION:

• [The exhaust fan shall operate at a constant speed.]
• [The exhaust fan speed shall be controlled for:]
  • [Fixed percentage of maximum speed (0%-100%)]
  • [Exhaust airflow (CFM)]
  • [Tracking of supply fan command]
  • [Tracking of supply fan airflow]
  • [Room static pressure]
• The unit shall attempt to start the exhaust fan when the exhaust fan delay timer expires. When the exhaust fan starts, the exhaust fan adjustable current switch shall close and remain closed until the fan is stopped.

EXHAUST FAN STATUS:

After a 90-second (adjustable) delay from the exhaust fan start signal, if the exhaust fan current switch is still open, the exhaust fan alarm shall be activated. Exhaust fan status shall only be active when the exhaust fan output is active and the exhaust fan current switch is closed. Exhaust fan status shall be inactive under all other circumstances.

FAN FIXED SPEED OPTION:

Analog voltage command to the exhaust fan VFD can be set from the unit controller screen [or provided by the BMS]. The adjustable range of 0% to 100% corresponds to the minimum and maximum fan operating speed (0 VCC minimum to 10 VCC maximum, adjustable). This exhaust fan operating mode can be used to balance exhaust airflow in the field.

EXHAUST AIRFLOW CONTROL OPTION:

The controller adjusts the exhaust fan VFD command to maintain the exhaust airflow at a setpoint. The exhaust airflow setpoint is entered and adjusted from the unit controller screen [or provided by the BMS]. Minimum and maximum values for the exhaust airflow setpoint are unit dependent. An adjustable PI (proportional and integral) loop compares the measured exhaust airflow to the airflow setpoint and adjusts fan speed. If the measured exhaust airflow varies by more than 10% (adjustable) from the desired airflow for more than 60 seconds (adjustable), an exhaust airflow alarm shall be triggered. This exhaust fan operating mode can be used to maintain constant exhaust airflow when unit filters are saturated.

SUPPLY FAN TRACKING CONTROL OPTION:

The controller adjusts the exhaust fan frequency drive command to track the supply fan command. Minimum (50%) and maximum (200%) tracking rates are adjustable. This exhaust fan operating mode can be used to maintain proportional commands of supply and exhaust fans when the supply fan modulates.

SUPPLY FAN AIRFLOW TRACKING CONTROL OPTION:

The controller adjusts the exhaust fan frequency drive command to track the supply fan airflow. Offset from supply airflow is adjustable from -25% to +25%. An adjustable PI (proportional and integral) loop compares the measured exhaust airflow to the airflow setpoint and adjusts fan speed. If the measured airflow at the outlet varies by more than 10% (adjustable) from the desired airflow for more than 60 seconds (adjustable), an outlet airflow alarm shall be triggered. This exhaust fan operating mode can be used to maintain proportional supply and exhaust airflows when the supply fan modulates and unit filters are loaded.

ROOM STATIC PRESSURE CONTROL OPTION:

The controller adjusts the exhaust fan frequency drive command to maintain room static pressure at a setpoint. Room static pressure is typically measured as the pressure difference between the room and an adjacent space or the outside. The room static pressure setpoint is entered and adjusted from the unit controller screen [or provided by the building automation system (BMS)]. Minimum and maximum values for the exhaust fan speed are adjustable. An adjustable PI (proportional and integral) loop compares the measured room static pressure to the static pressure setpoint and adjusts exhaust fan speed. If the measured static pressure varies by more than 0.05 inches of water column (adjustable) for more than 60 seconds (adjustable) from the desired static pressure, an exhaust air static pressure alarm shall be triggered. This exhaust fan operating mode can be used to maintain constant room static pressure in a zone to control infiltration or exfiltration from an adjacent zone or the outside.

ECONOMIZER (BYPASS) OPERATION:

Under normal operation, the bypass damper shall remain closed and the face damper open to allow for total energy recovery. In economizer mode, the bypass damper shall be open and the face damper closed to bypass the core. Economizer status can be controlled by temperature or enthalpy.

• TEMPERATURE: The economizer shall be locked out when:
  • Outdoor air temperature is below the economizer’s adjustable low lockout temperature.
  • Outdoor air temperature is above the economizer’s adjustable high lockout temperature.
• ENTHALPY: The economizer shall be deactivated when:
  • Outdoor air enthalpy is higher than return air enthalpy.
  • Outdoor air temperature is below the economizer’s adjustable low lockout temperature.

COOLING OPERATION:

Cooling shall be locked out if the outdoor air temperature is below 70 degrees (adjustable) or if heating is active. The temperature setpoint may be configured as constant (adjustable) or reset based on outdoor air temperature. Cooling shall be controlled using supply air temperature or return air temperature.

SUPPLY AIR CONSTANT TEMPERATURE OPTION:

The controller adjusts the 0 to 10 VCC analog output to the cooling device to maintain air temperature at a setpoint. The air temperature setpoint is entered and adjusted from the unit controller screen [or provided by the BMS]. Minimum and maximum values for the supply air temperature setpoint are unit dependent and adjustable. An adjustable PI (proportional and integral) loop compares the measured supply air temperature to the air temperature setpoint and adjusts the 0 to 10 VCC analog output. Two-stage cooling demand indicating digital outputs are also provided. Analog and digital outputs can be used to control a chilled water valve, remote DX condensing units, or a heat pump.

AIR TEMPERATURE RESET OPTION:

The controller adjusts the 0 to 10 VCC analog output to the cooling device to maintain air temperature at a setpoint. The air temperature setpoint is calculated based on outdoor air temperature. The air setpoint is adjusted between a maximum of 70 °F (adjustable) and a minimum of 55 °F (adjustable) when the measured temperature varies between a minimum of 70 °F (adjustable) and a maximum of 90 °F (adjustable). These values are entered and set from the unit controller screen [or provided by the BMS]. An adjustable PI (proportional and integral) loop compares the measured air temperature to the air temperature setpoint and adjusts the analog output. Two-stage cooling demand indicating digital outputs are also provided. Analog and digital outputs can be used to control a chilled water valve, remote DX condensing units, or a heat pump. Coil freeze protection shall be provided by others in the field.

HEATING OPERATION:

Heating shall be locked out if the outdoor air temperature is above 70 degrees (adjustable). The temperature setpoint may be configured as constant (adjustable) or reset based on outdoor air temperature. Heating shall be controlled using supply air temperature or return air temperature.

CONSTANT TEMPERATURE OPTION:

The controller energizes heating equipment or adjusts the 0 to 10 VCC analog output to the heating equipment to maintain air temperature at a setpoint. The air temperature setpoint is entered and set from the equipment controller screen [or provided by the BMS]. Minimum and maximum values for the air temperature setpoint are equipment dependent and adjustable. An adjustable PI (proportional and integral) loop compares the measured air temperature to the air temperature setpoint and adjusts the analog output. A digital output indicating heating demand is also provided. Analog and digital outputs can be used to control a hot water valve, electric heater, gas heater, or heat pump.

AIR TEMPERATURE RESET OPTION:

The controller adjusts the 0 to 10 VCC analog output to the heating device to maintain air temperature at a setpoint. The air temperature setpoint is calculated based on outdoor air temperature. The air setpoint is adjusted between a maximum of 100 °F (adjustable) and a minimum of 70 °F (adjustable) when the measured temperature varies between a minimum of 20 °F (adjustable) and a maximum of 70 °F (adjustable). These values are entered and adjusted from the unit controller screen [or provided by the BMS]. An adjustable PI (proportional and integral) loop compares the measured supply air temperature to the supply air temperature setpoint and adjusts the 0 to 10 VCC analog output. A digital output indicating heating demand is also provided. Analog and digital outputs can be used to control a hot water valve, electric heater, gas heater, or heat pump. Coil freeze protection shall be provided by others in the field.

2.7 FILTER SECTION

The ERV shall be equipped with 2-inch thick disposable pleated filters [MERV 8][MERV 13] located in the outdoor and exhaust air streams. All filters shall be accessible from the exterior of the unit.

2.8 COILS

• General: Coils shall be intended for use with water, glycol, or other suitable heat transfer fluids. Coils shall be designed to maximize performance under specified conditions with minimum air-side pressure drop.
• Certification: All water coils designed with 1/2" or 5/8" tubes shall be ARI certified and bear the ARI symbol. Coils not covered by ARI standard rating conditions or manufacturer’s certification program shall be acceptable, provided the manufacturer is a current member of the ARI coil certification program and the coils are rated in accordance with ARI Standard 410.
• Tubes: Tubes and return bends shall be fabricated from UNS C12200 seamless copper complying with ASTM B224 and ASTM E527 standards. Properties shall be O50 light annealed, with a maximum grain size of 0.040 mm. Tubes shall be mechanically expanded into fins (secondary surface) for maximum heat transfer. Materials shall have a diameter of 3/8 in. x (0.014, 0.022) wall thickness, a diameter of 1/2 in. x (0.016, 0.025) wall thickness, or a diameter of 5/8 in. x (0.020, 0.025, 0.035, 0.049) wall thickness. Enhanced rifled or lanced tubes may be offered as an option.
• Fins: Secondary surface (fins) shall be of the flat plate type in aluminum or copper, with collars formed by a die. Fin design shall be flat, corrugated, or sinusoidal, in a staggered tube pattern, to meet performance requirements. Collars shall maintain specified fin spacing and cover the entire tube surface. Aluminum properties shall be that of ASTM B209 alloy 1100, with O (soft) temper; copper shall be ASTM B152-06 alloy 11000, with soft (annealed) temper. Fins shall be free of oil and oxidation.
• Collectors: Collectors shall be fabricated from UNS C12200 seamless copper, Type L (drawn), sized to match the specified connection size. Optional Type K (drawn) copper collectors and Schedule 40 steel collectors shall be offered. Molded copper bosses shall be brazed inside collectors, unless plug-formed (for sizes up to 1-3/8"). 1/4 inch vents and drains shall be provided for all fluid coils.
• Fittings: Fittings shall be copper, Schedule 40 steel, or red brass. Fitting type shall be solder, MPT or FPT, grooved, or flanged, as required.
• Casing: Coil casing material shall be minimum 16-gauge G90 galvanized steel. Heavier gauge material, stainless steel, copper, or aluminum casings shall be provided if necessary. Intermediate tube supports shall be provided on all coils 48 inches and larger. Top and bottom coil casings shall be double flanged, allowing for vertical stacking of coils.
• Brazing: All coils shall be brazed with a filler material containing not less than 5% silver (BCup-3) to ensure joint integrity. A low-fume bronze brazing material with flux coating shall be used for ferrous and non-ferrous joints.
• Pressure Test: Coils shall be tested to 550 psig using dry nitrogen, submerged in water. A two-operator check shall be performed to ensure all coils are leak-free.
• Service Pressure and Temperature: Coils shall be designed to withstand a maximum temperature of 300 °F and a maximum pressure of 250 psig.
• Installation: Coils shall be installed in accordance with manufacturer’s instructions and applicable piping codes. System piping and risers shall be designed for velocities allowing adequate oil return throughout the system.

2.9 EVAPORATOR COILS

• General: Evaporator coils shall be intended for use in a wide range of applications and with various types of refrigerants. Coils shall be designed to maximize performance under specified conditions with minimum air-side pressure drop.
• Certification: Coils shall be UL listed as components containing refrigerants. Coils intended for use with R-410A refrigerant shall have undergone cyclic testing and be rated for 750 psig.
• Tubes: Tubes and return bends shall be fabricated from UNS C12200 seamless copper complying with ASTM B224 and ASTM E527 standards. Properties shall be O50 light annealed, with a maximum grain size of 0.040 mm. Tubes shall be mechanically expanded into fins (secondary surface) for maximum heat transfer. Materials shall have a diameter of 3/8 in. x (0.014, 0.022) wall thickness, a diameter of 1/2 in. x (0.016, 0.025) wall thickness, or a diameter of 5/8 in. x (0.020, 0.025, 0.035, 0.049) wall thickness. Enhanced rifled or lanced tubes may be offered as an option.
• Fins: Secondary surface (fins) shall be of the flat plate type in aluminum or copper, with collars formed by a die. Fin design shall be flat, corrugated, or sinusoidal, in a staggered tube pattern, to meet performance requirements. Collars shall maintain specified fin spacing and cover the entire tube surface. Aluminum properties shall be that of ASTM B209 alloy 1100, with O (soft) temper; copper shall be ASTM B152-06 alloy 11000, with soft (annealed) temper. Fins shall be free of oil and oxidation.
• Collectors: Collectors shall be fabricated from UNS C12200 seamless copper, Type L (drawn), sized to match the specified connection size. Optional Type K (drawn) copper collectors shall be offered. Molded copper bosses shall be brazed inside collectors, unless plug-formed (for sizes up to 1-3/8").
• Fittings: Evaporator coils shall be designed with brass liquid distributors (as required) and copper solder suction fittings. Distributors shall be plugged with soft solder to facilitate plug removal; suction fittings shall be plugged.
• Casing: Coil casing shall be minimum 16-gauge G90 galvanized steel. Heavier gauge material, stainless steel, copper, or aluminum casings shall be provided if necessary. Intermediate tube supports shall be provided on all coils 48 inches and larger. Top and bottom coil casings shall be double flanged, allowing for vertical stacking of coils.
• Brazing: All coils shall be brazed with a filler material containing not less than 5% silver (BCup-3) to ensure joint integrity.
• Pressure Test: Coils shall be tested to 550 psig using dry nitrogen, submerged in water. A two-operator check shall be performed to ensure all coils are leak-free. Coils shall be shipped with a nitrogen charge to verify tightness and prevent moisture migration into the coil.
• Service Pressure: Coils shall be certified to withstand service pressures of 750 psig.
• Installation: Coils shall be installed in accordance with manufacturer’s instructions and applicable piping codes. System piping and risers shall be designed for velocities allowing adequate oil return throughout the system.

PART 3 – EXECUTION

3.1 EXAMINATION

• Prior to commencing installation, examine the area and conditions to verify that the location is correct and complies with installation tolerances and other conditions affecting equipment performance. Consult the equipment operation and maintenance manual.
• Examine the rough-in of plumbing, electrical, and HVAC system to verify actual location and compliance with unit requirements. Consult the unit operation and maintenance manual.
• Do not proceed with installation until all unsatisfactory conditions have been corrected.

3.2 INSTALLATION

• Installation shall be performed in accordance with these written specifications, project drawings, manufacturer’s installation instructions as documented in the manufacturer’s operation and maintenance manual, best practices, and all applicable building codes.
• Install the equipment maintaining necessary clearances for servicing and maintenance.

3.3 CONNECTIONS

In all cases, industry best practices shall be followed. Connections shall be made in accordance with the installation requirements indicated above.

• Duct installation and connection requirements are specified in Division 23 of this document.
• Electrical installation requirements are specified in Division 26 of this document.

3.4 SITE QUALITY CONTROL

The contractor shall inspect the assembled components on site and the installation of the equipment, including electrical and piping connections. The contractor shall submit results in writing to the architect/engineer. Inspection shall include a complete commissioning checklist comprising (at a minimum) the following items: Completed commissioning checklists, as shown in the manufacturer’s operation manual. Insert any other requirements here.

3.5 COMMISSIONING SERVICE

The contractor shall perform commissioning service. Clean the entire unit, comb coil fins if necessary, and install clean filters. Verify that the water source complies with the manufacturer’s requirements for flow and temperature. Measure and record electrical voltage and amperage values. Refer to Division 23 “Testing, Adjusting, and Balancing” and comply with provisions therein.

3.6 DEMONSTRATION AND TRAINING

The contractor shall train the owner’s maintenance personnel on the adjustment, operation, and maintenance of the entire makeup air unit. Refer to Division 01, section “Closeout Procedures, Demonstration, and Training.”