RenewAire HE-1XIN Air-to-Air Energy Recovery Ventilator

Part 1 - General

1.1 Summary

• This section includes Air-to-Air Energy Recovery Ventilators for indoor installation.
• Within this document, these units may be referred to as Energy Recovery Ventilator (ERV) for brevity.

1.2 Related

Drawing and general provisions of the contract, including General Requirements Division 01, Division 23, Division 23 Specifications Sections, and common work requirements for HVAC apply to work specified in this section.

• Section 23 09 00: Controls and Instrumentation

1.3 Submittals

Product data for each type or model of Energy Recovery Ventilator, including:

• Unit performance data for both Supply Air and Exhaust Air, with system operating conditions indicated.
• Enthalpy plate performance data for both summer and winter operation.
• Motor ratings and unit electrical characteristics.
• Dimensioned drawings for each type of installation, showing isometric and plan views, to include location of attached ductwork and service clearance requirements.
• Estimated gross weight of each installed unit.
• Filter types, quantities, and sizes.
• Installation, Operating and Maintenance manual (IOM) for each model.

LEED Submittals:

• Provide data for prerequisite E01: Documentation indicating that units comply with ASHRAE 62.1-2010, Section 5 - "Systems and Equipment".
• Shop Drawings: For air-to-air energy recovery ventilators, include plans, elevations, sections, details, and attachments to other work.
• Detail equipment assemblies and indicate dimensions, weights, loads, required clearances, method of field assembly, components, and location and size of each field connection.
• Wiring Diagrams: For power, signal, and control wiring.
• Operation and maintenance data for air-to-air energy recovery ventilator.

1.4 Quality Assurance

• Source Limitations: Obtain Air-to-Air Energy Recovery Ventilator with all appurtenant components or accessories from a single manufacturer.
• Workforce: For fabrication, installation, and testing, use only thoroughly trained and experienced workers familiar with the items and manufacturer's current recommended installation methods.
• Warranty: The ERV core is warranted for ten (10) years against manufacturing defects. The balance-of-unit is warranted for two (2) years from the date of installation.
• Testing: Manufacturer shall provide evidence of independent testing by Underwriters Laboratory (UL) verifying a maximum flame spread index (FSI) of 25 and a maximum smoke developed index (SDI) of 50, meeting NFPA90A and NFPA 90B requirements. Method of test shall be UL Standard 723.
• Certifications: Energy recovery cores must be third-party Certified by AHRI under its Standard 1060 for Energy Recovery Ventilators. Certifications shall confirm published performance for airflow, static pressure, temperature, total effectiveness, purge air (OACF), and exhaust air leakage (EATR). OACF shall be no more than 1.02 and EATR shall be at 0% against balanced airflow.
• Listings: Entire unit shall be listed under UL 1812 Standard for Ducted Air to Air Heat Exchangers and comply with CSA Standard 22.2.
• Factory Testing: Every unit to be factory tested prior to shipping, including: Motor Dielectric Voltage-Withstand Bench Test, Unit Dielectric Voltage-Withstand Test, Continuity of Internal Control Circuits Test, Unit Amperage Test.

1.5 Coordination

• Coordinate size and location of all building penetrations required for installation of each Energy Recovery Ventilator and associated electrical systems.
• Coordinate sequencing of construction for associated plumbing, HVAC, and electrical supply.

Part 2 - Products

2.1 Manufacturers

• Available Manufacturers: Subject to compliance with specifications, manufacturers offering products that may be incorporated include, but are not limited to: RenewAire.
• Manufacturer should be in business for a minimum of 10 years manufacturing energy recovery ventilators.

2.2 Manufactured Units

Air-to-Air Energy Recovery Ventilators shall be fully assembled at the factory and consist of:

• A fixed-plate cross-flow heat exchanger with no moving parts.
• An insulated [single][double] wall [G90 galvanized][painted] 20-gauge steel cabinet.
• [Motorized outside air intake damper,] filter assemblies for both intake and exhaust air.
• Enthalpy core.
• Supply air blower assembly.
• [Motorized return air damper,] exhaust air blower assembly.
• Electrical control box with all specified components and internal accessories factory installed and tested, prepared for single-point high voltage connection.

The entire unit, with the exception of field-installed components, shall be assembled and test operated at the factory.

2.3 Cabinet

• Materials: Formed [single][double] wall insulated metal cabinet, fabricated to permit access to internal components for maintenance.
• Outside Casing: 20 gauge, galvanized (G90) steel meeting ASTM A653 for components that do not receive a painted finish. [Painted components as supplied by the factory shall have polyester urethane paint on 20 gauge G90 galvanized steel.]
• Access Doors: Hinged with airtight closed cell foam gaskets. Door pressure taps, with captive plugs, provided for cross-core pressure measurement allowing for accurate airflow measurement.
• Duct Connections: Factory-installed duct flanges on all duct openings.
• Cabinet Insulation: Unit walls and doors insulated with 1 inch, 4 pound density, foil/scrim faced, high density fiberglass board insulation, providing a cleanable surface and eliminating the possibility of exposing fresh air to glass fibers. Minimum R-value of 4.3 (hr-ft²-°F/BTU).
• Enthalpy Core: Total enthalpy type, capable of transferring both sensible and latent energy between airstreams. Latent energy transfer via direct water vapor transfer. No condensate drains allowed. Designed and constructed to permit cleaning and removal for servicing. Ten-year warranty. Performance criteria as specified in AHRI Standard 1060.
• Control Center / Connections: Electrical control center for all high and low voltage connections. Constructed to permit single-point high voltage power supply connections to the [non-fused][fused] disconnect.
• Passive Frost Control: ERV core performs without condensing or frosting under normal operating conditions (outside temperatures above -10°F and inside relative humidity below 40%). No condensate drains allowed.
• Motorized Isolation Damper(s): [None included.][Return Air][and][Outside Air][motorized damper(s)][of an AMCA Class I low leakage type shall be factory installed.]

2.4 Blower Section

• Construction: Blower assemblies consist of a [120V][208-230V][277V][460V][1 Phase][3 Phase] 60 HZ, [ODP][ECM] motor, and a [direct] driven forward-curved blower.
• Balancing: Statically and dynamically balanced and designed for continuous operation at maximum rated fan speed and horsepower.

2.5 Motors

• Efficiency: Blower motors shall be Premium Efficiency, EISA compliant. Motors shall be totally enclosed (TEFC) and supplied with factory installed motor starters. Direct drive models (EV450 and HE1X models) shall be EISA-compliant for energy efficiency with open drip proof design and integral thermal protection.

2.6 Unit Controls

• Fan Control: [Single contactor for common fan control.][Dual contactors for independent blower control.][Terminal strip for EC motors.]
• Bypass Economizer Control: [Dry bulb][Differential enthalpy] control, 2 position dampers with 100% airflow through the core or 100% airflow bypassing the core.
• Sensors: [None.][Dirty filter monitor for both airstreams.]
• Timeclock: Digital Time Clock [wall mount][mounting in outdoor, enclosed NEMA 3R enclosure], with up to 8 on/off cycles per day or 50 per week, 24VAC power, with battery backup protection of program settings against power failure to energize unit.
• Motion (Occupancy) Sensor: Passive infrared sensor for [wall][ceiling] mounting with adjustable time-off delay to 30 minutes, 24VAC power to energize unit.
• Carbon Dioxide: Adjustable control from 600 - 2000 PPM for [wall][duct] mounting with digital display.
• Factory-Installed Microprocessor Controller and Sensors: [Enhanced][Premium] ERV controls that:
  • Comply with requirements in Division 23 Section "Sequence of Operations for HVAC Controls".
  • Have factory-installed hardware and software to enable building automation interface via [Modbus][BACnet] to monitor, control, and display status and alarms.
  • Capable of operating at temperatures between -20°F to 160°F.
  • DIN rail mounting type.
  • Backlit display for menu-driven display for navigation and control of unit.
  • Ability to communicate with the BMS via Modbus RTU/TCP and BACnet MSTP/IP.
  • Integrated Ethernet interface and a web server for displaying unit parameters.
  • Near field communication (NFC) capability for Android devices.
  • Internal programmable time clock for user to add up to different occupancy schedules and add holidays.
  • Capable of integral diagnostics.
  • Capable of IP or SI unit display.
  • Battery powered clock.
  • Minimum of three modes for determining occupancy: a dry contact, the internal time clock, or the BMS.
  • Remote user terminal for remote monitoring and adjustment of parameters.
  • Minimum of (10) universal inputs/outputs (AI, DI, AO) and (6) six relay outputs (DO).
  • Integrated fieldbus port.
  • Capability for I/O expansion.
  • Micro USB port to load application program, unit parameters, saving logs, etc.
• Required Sensors for Control:
  • (2) Temperature sensor for fresh air and exhaust air.
  • (2) Temperature and humidity sensor for outside air, return air.
  • (2) Differential pressure sensors for filter alarms.
  • [(2) Differential pressure sensors for measuring pressure drop across energy recovery core and for determining airflow in both airstreams].
  • (2) Adjustable current switches.
  • [Field-installed duct or room IAQ sensor].
  • [Field-installed duct or room CO2 sensor].
  • [Field-installed duct static sensor].
  • [Field-installed room pressurization sensor].
• Alarm Monitoring: Capability to monitor unit conditions for alarm conditions. Upon detecting an alarm, record alarm description, time, date, available temperatures, and unit status. A digital output reserved for remote alarm indication. Alarms communicated via BMS as applicable. Alarm functions include:
  • Outside air temperature sensor alarm.
  • Outside 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 proving alarm.
  • [Outside airflow sensor alarm].
  • [Exhaust airflow sensor alarm].
  • [Duct static pressure sensor alarm].
  • [Room pressurization sensor alarm].
  • [CO2 sensor alarm].
  • [TVOC sensor alarm].
  • [Airflow out of range alarm].
• Microprocessor Controller Display:
  • Unit on.
  • [Unit economizer/bypass mode].
  • [Heating status].
  • Outdoor air temperature.
  • Outdoor air humidity.
  • Return air temperature.
  • Return air humidity.
  • Supply air temperature.
  • [Airflows in both airstreams].
  • Unit on/off.
  • Fan on/off.
  • Damper status.
  • Alarm digital display.
• Operating Sequences: Factory pre-programmed multiple operating sequences for control of the ERV. Factory default settings adjustable in the field. Available sequences include:
  • DDC Controller: Integral LCD readout for set points and unit operation monitoring. Provided with required sensors and programming. Factory programmed, mounted, and tested. Integral USB and Ethernet ports for updating programs and retrieving log files.
  • BMS Interface: [BACnet MS/TP], [BACnet IP], [Modbus RTU], [Modbus TCP].

Sequence of Operations

General Operation

• Power Up: Unit main disconnect closed initiates a 10-second delay (adjustable) for the controller to come online.

ERV Unit Start Command

• An input signal is required to enable unit operation. Unit commanded on by:
  • [Digital input].
  • [BMS command].
  • [Internal time clock].
  • [Enable via controller display].
• All enabled input types must be true before the unit will start.
• Exhaust fan starts after a 3-second delay (adjustable), and will not start until the damper actuator end switch closes.
• Supply fan starts after a 6-second delay (adjustable), and will not start until the damper actuator end switch closes.
• Supply fan, exhaust fan, [economizer], [heating] are controlled based on chosen unit operating modes and air conditions.

ERV Unit Stop Command (or De-energized)

• Unit can be commanded off by:
  • [Digital input].
  • [BMS command].
  • [Internal time clock].
  • [Disable via controller display].
• Supply fan and exhaust fan are de-energized.
• All dampers are unpowered and spring return to their default position after a 10-second delay (adjustable).

Supply Fan Operation

• [The supply fan will operate at a constant speed.]
• [The supply fan speed will be controlled for:]
  • [Fixed percentage of max speed (0%-100%)].
  • [Supply air flow (CFM)].
  • [Supply duct static pressure].
  • [Room pressure].
  • [IAQ (TVOC)].
  • [Fixed CO2].
  • [CO2 flow].
• Unit attempts to start the supply fan when the supply fan delay timer expires. When the supply fan starts, the supply fan adjustable current switch should close and remain closed until the fan is turned off.

Supply Fan Status

• Once the supply fan current switch closes, [heating] operation is allowed. After a 90-second delay (adjustable) from supply fan start signal, if the supply fan current switch is still open, the supply fan alarm should be set to true and [heating] operation shall be prohibited. Supply fan status is true only when the supply fan output is on and supply fan current switch is closed. Supply fan status is false in all other circumstances.

Fixed Fan Speed Option

• Analog voltage command to the supply fan ECM can be set from the unit controller display [or by the BMS]. Adjustable range of 0% to 100% corresponds to the minimum and maximum fan operating speed. This option can be used to field balance the supply air flow rate.

Supply Air Flow Control Option

• Controller adjusts the supply fan ECM command to maintain the supply air flow rate at a set point. Set point entered and adjusted from the unit controller display [or provided by the BMS]. Minimum and maximum values for supply air flow rate set point are unit dependent. An adjustable PI loop compares measured supply air flow to the set point and adjusts fan speed. If measured supply air flow rate varies more than 10% (adjustable) for more than 60 seconds (adjustable), a supply air flow rate alarm will be set to true. This mode can provide a constant supply air flow rate as unit filters become loaded.

Supply Duct Static Pressure Control Option

• Controller adjusts the supply fan ECM command to maintain the supply duct static pressure at a set point. Set point entered and adjusted from the unit controller display [or provided by the BMS]. Minimum and maximum values for supply duct static pressure set point are unit dependent. An adjustable PI loop compares measured supply duct static pressure to the set point and adjusts fan speed. If measured static pressure varies more than 0.05 inches water gauge (adjustable) for more than 60 seconds (adjustable), a supply air static pressure alarm will be set to true. This mode can provide a constant supply duct pressure for VAV systems.

Room Static Pressure Control Option

• Controller adjusts the supply fan ECM command to maintain the room static pressure at a set point. Room static pressure measurement is typically a differential pressure measurement between the room and an adjacent space or outdoors. Set point entered and adjusted from the unit controller display [or provided by the BMS]. Minimum and maximum values for exhaust fan speeds are adjustable. An adjustable PI loop compares measured room static pressure to the set point and adjusts supply fan speed. If measured static pressure varies more than 0.05 inches water gauge (adjustable) for more than 60 seconds (adjustable), a supply air static pressure alarm will be set to true. This mode can provide a constant static pressure in an area to control infiltration or exfiltration from an adjacent area or outdoors.

IAQ (TVOC) Control Option

• Controller adjusts the supply fan ECM command to maintain the room or return air VOC level at a set point. VOC set point entered and adjusted from the unit controller display [or provided by the BMS]. An adjustable PI loop compares measured VOC level to the set point and adjusts fan speed. Minimum and maximum fan speed commands are adjustable. If measured VOC level exceeds 1000 ppm (CO2 equivalent, adjustable) for more than 60 seconds (adjustable), a VOC alarm will be set to true. This mode can provide demand controlled ventilation of a space. Minimum fan speed provides required minimum outdoor air when VOC level is at or below the VOC set point.

CO2 Control Option

• Controller adjusts the supply fan ECM command to maintain the room or return air CO2 level at a set point. CO2 set point entered and adjusted from the unit controller display [or provided by the BMS]. An adjustable PI loop compares measured CO2 level to the set point and adjusts fan speed. Minimum and maximum fan speed commands are adjustable. If measured CO2 level exceeds 1000 ppm (adjustable) for more than 60 seconds (adjustable), a CO2 alarm will be set to true. This mode can provide demand controlled ventilation of a space. Minimum fan speed provides required minimum outdoor air when CO2 level is at or below the CO2 set point.

CO2 Flow Control Option

• Controller adjusts the supply fan ECM command based on measured room or return air CO2 level. Supply air flow set point derived from user entered minimum and maximum CO2 levels and minimum and maximum desired air flow rates. When CO2 level is at or below the minimum CO2 level, air flow set point is at the minimum. When CO2 level is at or above the maximum CO2 level, air flow set point is at the maximum. Between minimum and maximum CO2 levels, air flow set point is linearly scaled. If measured CO2 level exceeds 1000 ppm (adjustable) for more than 60 seconds (adjustable), a CO2 alarm will be set to true. This mode can provide demand controlled ventilation of a space. Minimum fan speed provides required minimum outdoor air when CO2 level is at or below the CO2 set point.

Exhaust Fan Operation

• [The exhaust fan will operate at a constant speed.]
• [The exhaust fan speed will be controlled for:]
  • [Fixed percentage of max speed (0%-100%)].
  • [Exhaust air flow (CFM)].
  • [Supply fan command tracking].
  • [Supply fan flow rate tracking].
  • [Room static pressure].
• Unit attempts to start the exhaust fan when the exhaust fan delay timer expires. When the exhaust fan starts, the exhaust fan adjustable current switch should close and remain closed until the fan is turned off.

Exhaust Fan Status

• After a 90-second delay (adjustable) from exhaust fan start signal, if exhaust fan current switch is still open, the exhaust fan alarm should be set to true. Exhaust fan status is true only when the exhaust fan output is on and exhaust fan current switch is closed. Exhaust fan status is false in all other circumstances.

Fixed Fan Speed Option

• Analog voltage command to the exhaust fan ECM can be set from the unit controller display [or provided by the BMS]. Adjustable range of 0% to 100% corresponds to the minimum and maximum fan operating speed (0 VDC minimum to 10 VDC maximum, adjustable). This option can be used to field balance the exhaust air flow rate.

Exhaust Air Flow Control Option

• Controller adjusts the exhaust fan ECM command to maintain the exhaust air flow rate at a set point. Set point entered and adjusted from the unit controller display [or provided by the BMS]. Minimum and maximum values for exhaust air flow rate set point are unit dependent. An adjustable PI loop compares measured exhaust air flow to the set point and adjusts fan speed. If measured exhaust air flow rate varies more than 10% (adjustable) for more than 60 seconds (adjustable), an exhaust air flow rate alarm will be set to true. This mode can provide a constant exhaust air flow rate as unit filters become loaded.

Supply Fan Command Tracking Control Option

• Controller adjusts the exhaust fan ECM command to track the supply fan command. Minimum (50%) and maximum (200%) tracking rates are adjustable. This mode can maintain proportional supply and exhaust fan commands as the supply fan modulates.

Supply Fan Flow Tracking Control Option

• Controller adjusts the exhaust fan ECM command to track the supply fan air flow rate. Offset from the supply air flow rate is adjustable from -25% to +25%. An adjustable PI loop compares measured exhaust air flow to the set point and adjusts fan speed. If measured exhaust air flow rate varies more than 10% (adjustable) for more than 60 seconds (adjustable), an exhaust air flow rate alarm will be set to true. This mode can maintain proportional supply and exhaust air flows as the supply fan modulates and as the unit filters become loaded.

Room Static Pressure Control Option

• Controller adjusts the exhaust fan ECM command to maintain the room static pressure at a set point. Room static pressure measurement is typically a differential pressure measurement between the room and an adjacent space or outdoors. Set point entered and adjusted from the unit controller display [or provided by the BMS]. Minimum and maximum values for exhaust fan speeds are adjustable. An adjustable PI loop compares measured room static pressure to the set point and adjusts exhaust fan speed. If measured static pressure varies more than 0.05 inches water gauge (adjustable) for more than 60 seconds (adjustable), an exhaust air static pressure alarm will be set to true. This mode can provide a constant static pressure in an area to control infiltration or exfiltration from an adjacent area or outdoors.

Economizer (Bypass) Operation

• During normal operation, the bypass damper remains closed and the face damper opens to allow full energy recovery. During economizer operation, the bypass damper opens and the face damper closes to bypass the core. The economizer state can be controlled by temperature or enthalpy.
• Temperature Lockout: Economizer locked out when outside air temperature is less than the adjustable low lockout or greater than the adjustable high lockout.
• Enthalpy Lockout: Economizer locked out when outside air enthalpy is greater than return air enthalpy, or outside air temperature is less than the field adjustable low lockout.

Heating Operation

• Heating locked out if outdoor air temperature is above 70 degrees (adjustable). Temperature set point can be configured as constant (adjustable) or reset by the outside air temperature. Heating controlled using supply air temperature or return air temperature.
• Constant Temperature Option: Controller stages heaters or adjusts 0-10 VDC analog output to maintain air temperature at a set point. Set point entered and adjusted from the unit controller display [or provided by the BMS]. Minimum and maximum values for air temperature set point are unit dependent and adjustable. An adjustable PI loop compares measured air temperature to the set point and adjusts the analog output. A digital output indicates a call for heating. Analog and digital output can control a hot water valve, electric heater, gas heater, or heat pump.
• Reset Air Temperature Option: Controller adjusts 0-10 VDC analog output to maintain air temperature at a set point. Air temperature set point calculated based on outdoor air temperature. Set point adjusted between 100°F maximum (adjustable) and 70°F minimum (adjustable) as measured temperature varies from 20°F minimum (adjustable) to 70°F maximum (adjustable). Values entered and adjusted from the unit controller display [or provided by the BMS]. An adjustable PI loop compares measured supply air temperature to the set point and adjusts the 0-10 VDC analog output. A digital output indicates a call for heating. Analog and digital output can control a hot water valve, electric heater, gas heater, or heat pump. Coil freeze protection must be provided by others in the field.

2.7 Filter Section

• ERV shall have 2" thick [MERV 8][MERV 13] disposable pleated filters located in the outdoor air and exhaust airstreams. All filters shall be accessible from the exterior of the unit.

Part 3 - Execution

3.1 Examination

• Prior to start of installation, examine area and conditions to verify correct location for compliance with installation tolerances and other conditions affecting unit performance. See unit IOM.
• Examine roughing-in of plumbing, electrical and HVAC services to verify actual location and compliance with unit requirements. See unit IOM.
• Proceed with installation only after all unsatisfactory conditions have been corrected.

3.2 Installation

• Installation shall be accomplished in accordance with these written specifications, project drawings, manufacturer's installation instructions as documented in manufacturer's IOM, Best Practices, and all applicable building codes.
• Install unit with clearances for service and maintenance.

3.3 Connections

• In all cases, industry Best Practices shall be incorporated. Connections are to be made subject to the installation requirements shown 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 Field Quality Control

• Contractor to inspect field assembled components and equipment installation, to include electrical and piping connections. Report results to Architect/Engineer in writing. Inspection must include a complete startup checklist as found in manufacturer's IOM. Insert any other requirements here.

3.5 Start-Up Service

• Contractor to perform startup service. Clean entire unit, comb coil fins as necessary, and install clean filters. Measure and record electrical values for voltage and amperage. Refer to Division 23 "Testing, Adjusting and Balancing" and comply with provisions therein.

3.6 Demonstration and Training

• Contractor to train owner's maintenance personnel to adjust, operate and maintain the entire Make-Up Air unit. Refer to Division 01 Section Closeout Procedures and Demonstration and Training.