Bard ERV-FA2 Wall Mount Energy Recovery Ventilator with Exhaust Installation Guide

INSTALLATION INSTRUCTIONS
Wall Mount Energy Recovery Ventilator
with Exhaust
Models:
ERV-FA2 ERV-FC2
ERV-FA3 ERV-FC3
For Use with Bard 1.5 – 3 Ton
Wall Mount Air Conditioners and Heat Pumps

ERV-FA2 Wall Mount Energy Recovery Ventilator with Exhaust

WARNING
Electrical shock hazard.
Disconnect remote electrical power supply or supplies before servicing.
Failure to do so could result in electric shock or death.
WARNING
Exposed moving parts.
Disconnect electrical power before servicing.
Failure to do so could result in severe injury or amputation.
CAUTION
Cut hazard.
Wear gloves to avoid contact with sharp edges.
Failure to do so could result in personal injury.

Model Nomenclature

Electrical Specifications

General Information

The ventilator should only be installed by a trained heating and air conditioning technician. These instructions serve as a guide to the technician installing the ventilator package. They are not intended as a stepby-step procedure with which the mechanically  inclined owner can install the package.
The ventilator housing is shipped in one carton which contains the following:

• Energy recovery ventilator
• Exhaust damper assembly
• Service door
• Rain hood and mist eliminator
• Installation instructions

Field-Supplied Tools Needed

• Appropriate personal protection equipment, including gloves and safety glasses
• 5/16″ nut driver
• Phillips head screwdriver
• Small flat head screwdriver for securing wire in terminal blocks
• Electrical tools
• Multimeter

Unpacking

Upon receipt of the equipment, be sure to compare the model number found on the shipping label with the accessory identication information on the ordering and shipping document to verify that the correct accessory has been shipped.
Inspect the carton housing of each ventilator as it is received and, before signing the freight bill, verify that all items have been received and that there is no visible damage. Note any shortages or damage on all copies of the freight bill. The receiving party must  contact the last carrier immediately, preferably in writing, requesting inspection by the carrier’s agent. Concealed damage not discovered until after loading must be reported to the carrier within 15 days of its receipt.

Description

The energy recovery ventilator was designed to provide energy efficient, cost effective ventilation to meet IAQ (indoor air quality) requirements while still maintaining good indoor comfort and humidity control for a variety of applications such as schools,  classrooms, lounges, conference rooms, beauty salons and others. It provides a constant supply of fresh air for control of airborne pollutants including CO2, smoke, radon, formaldehyde, excess moisture, virus and bacteria.
The ventilator incorporates rotary heat exchanger technology to remove both heat and moisture.
It is designed as a single package which can be easily factory or field installed for new installations or retrofit to the Bard WA and WH series wall-mounted units.
The package consists of a unique rotary energy recovery cassette that can be easily removed for cleaning or maintenance. The ERV-F3 has two 13″ diameter heat transfer wheels whereas the ERV-F2 has one 13″ diameter heat transfer wheel. The heat transfer  wheels use a permanently bonded dry desiccant coating for total heat recovery.
Ventilation is accomplished with two blower/motor assemblies each consisting of a drive motor and dual blowers for maximum ventilation at low sound levels.
The intake and exhaust blowers can be operated at the same speed (airflow rate) or different speeds to allow flexibility in maintaining desired building pressurization conditions. Factory shipped on medium intake and low exhaust. See Figure 6 on page 12 to  change speeds.
The rotating energy wheels provide the heat transfer effectively during both summer and winter conditions. Provide required ventilation to meet the requirements of ASHRAE 62.1 standard.

NOTE: During operation below 5°F outdoor temperature, freezing of moisture in the heat transfer wheel can occur. Consult the factory if this possibility exists.

Performance and Application Data – ERV-F*2

Summer Cooling Performance
(Indoor Design Conditions 75°DB/62°WB)

Winter Heating Performance
(Indoor Design Conditions 70°F DB)

LEGEND:
VLT = Ventilation Load – Total
VLS = Ventilation Load – Sensible
VLL = Ventilation Load – Latent
HRT = Heat Recovery – Total
HRS = Heat Recovery – Sensible
HRL = Heat Recovery – Latent
WVL = Winter Ventilation Load
WHR = Winter Heat Recovery

NOTE: All performance data is based on operating intake and exhaust blower on the same speed.

Performance and Application Data – ERV-F*3

Summer Cooling Performance
(Indoor Design Conditions 75°DB/62°WB)

Winter Heating Performance
(Indoor Design Conditions 70°F DB)

LEGEND:
VLT = Ventilation Load – Total
VLS = Ventilation Load – Sensible
VLL = Ventilation Load – Latent
HRT = Heat Recovery – Total
HRS = Heat Recovery – Sensible
HRL = Heat Recovery – Latent
WVL = Winter Ventilation Load
WHR = Winter Heat Recovery

NOTE: All performance data is based on operating intake and exhaust blower on the same speed.

Basic Field Installation

1. Unpack the ventilator assembly which includes the integral ventilator with attached electrical harness and miscellaneous hardware.
   WARNING
   Open and lock unit disconnect switch before installing this accessory to prevent injury or death due to electrical shock or contact with moving parts. Turn thermostat to OFF.

2. Disconnect unit power.

3. Remove the existing exterior blower access, lter access and vent option panels on the wall-mount unit (see Figure 1). Save the blower access and filter access panels and discard the vent option panel.
   TABLE 1
   Model Reference
   ** Model| For Use with the Following Units| Electrical**
   ---|---|---
   ERV-FA2| W18AB-A
   W18AY-A
   W24AB-A, -B
   W24AY-A, -B| W18HB-A
   W18HY-A
   W24HB-A, -B
   W24HY-A, -B| 230/208V
   1 or 3 phase
   ERV-FC2| W24AB-C
   W24AY-C| W24HB-C
   W24HY-C| 460V
   3 phase
   ERV-FA3| W30AB-A, -B
   W30AY-A, -B
   W36AB-A, -B
   W36AY-A, -B| W30HB-A, -B
   W30HY-A, -B
   W36HB-A, -B
   W36HY-A, -B| 230/208V
   1 or 3 phase
   ERV-FC3| W30AB-C
   W30AY-C
   W36AB-C
   W36AY-C| W30HB-C
   W30HY-C
   W36HB-C
   W36HY-C| 460ERV-F
   3 phase

FIGURE 1
Remove Access Panels CAUTION
Be sure the correct model and voltage energy recovery ventilator is used with the correct air conditioner or heat pump to ensure correct voltage compatibility.

4. Verify what type of filter racks are in the unit. Unit may include either a filter partition and tray assembly, or two separate filter brackets. If the unit contains two separate filter brackets, remove and save existing unit return air filter. Remove left-side
   filter support bracket by unscrewing two (2) screws from left side of unit. Remove and save top four (4) screws from front grille (see Figure 2). If the unit contains a partition and tray assembly, this may be left as-is for the ventilator installation.

5. Remove and discard exhaust cover plate (see Figure 2). Re-install left filter bracket, if applicable: Install W18 and W24 brackets as shipped; install W30 and W36 brackets straight.
   W30 and W36 Models Only: Install the filter fill on the top rear of the filter bracket. Bend up and fasten with two (2) self-drilling screws.
   FIGURE 2
   Remove Filter, Filter Support Bracket and Exhaust Cover Plate
   

6. Insert ventilator into the unit to the far left side, making sure to clear the right filter bracket. Once the ventilator is fully inserted, slide the ventilator to the right until it is tight against the back of the control panel (see Figure 3).
   IMPORTANT NOTE: Position front lip of ventilator over front grille and on top of condenser partition (see Figure 3 inset). This is important to ensure proper drainage of any water entering damper assembly.

7. Re-install left side filter support bracket, filter fill and air fiter removed during Step 4, if applicable (see Figure 2).

8. Remove outer and inner control panel covers.

9. Remove female plug of high voltage wiring harness (3-pin plug) from the heat recovery assembly and snap into unit control panel (from inside control panel) in the hole provided. Wire to top of compressor contactor (L1/L2) per Figure 4. Connect high  voltage plugs back together (see Figures 3 and 4).
   FIGURE 3
   Install Ventilator
   

10. Plug low voltage plug (12-pin plug) from the heat recovery unit into the front side of the control panel (see Figures 3 and 4).
    NOTE: These 24 volt control wires control the starting and stopping of the energy recovery ventilator and can be independently controlled by an energy management control or timer. See Control Wiring on page 11.

11. Replace inner and outer control panel covers.

12. Ventilator checkout
    A. Resupply power to unit.
    B. Energize the “A” occupancy 24 volt signal on the low voltage terminal strip (jumper “R” to “A”).
    FIGURE 4
    Install Low and High Voltage Plugs and Wiring
    C. Ventilator heat transfer wheels should rotate slowly (49 RPM). Intake and exhaust blowers should run and indoor comfort blower should run.
    D. De-energize the “A” terminal. The energy recovery wheels, fresh air, exhaust air and indoor comfort blowers should stop.
    E. This completes ventilator checkout.

13. Re-install the blower access and filter access panels at top of unit and secure with sheet metal screws.

14. Replace the vent option access panel with the new panel provided. Attach air intake hood with screws provided (see Figure 5). Be sure to insert the top flange of the air intake hood into and through the slot of the service door and between the door and insulation to prevent bowing of the door.

15. Apply certification label, included with installation instructions, next to unit serial plate.

16. Ventilator is now ready for operation.
    FIGURE 5
    Install Fresh Air Intake Hood Assembly
    

Control Wiring

The ERV-F comes from the factory with the low voltage control wires connected to the wall mount low voltage terminal strip. Care must be taken when deciding how to control the operation of the ventilator. When designing the control circuit for the ventilator,  the following requirements must be met. Control Requirements

1. Indoor blower motor will automatically run whenever the ERV-F is run.
2. Select the correct motor speed tap in the ERV-F. Using Table 2, determine the motor speed needed to get the desired amount of ventilation air needed. For instance, do not use the high speed tap on a ERV-F*3 if only 250 CFM of ventilation air is needed.  Use the low speed tap instead (see VENTILATION AIRFLOW for information on moving the speed taps). Using the high speed tap would serve no useful purpose and significantly affect the overall efficiency of the air conditioning system. System  operating cost would also increase.
   TABLE 2
   Ventilation Air (CFM) Model| High Speed (Black)| Medium Speed (Blue)| Low Speed (Red)
   ---|---|---|---
   ERV-FA2 ERV-FC2| 250| 225| 200
   ERV-FA3 ERV-FC3| 400| 325| 250
3. Run the ERV-F only during periods when the conditioned space is occupied. Running the ERV-F during unoccupied periods wastes energy, decreases the expected life of the ERV-F and can result in a large moisture buildup in the structure.
   The ERV-F removes 60-70% of the moisture in the incoming air, not 100% of it. Running the ERV-F when the structure is unoccupied allows moisture to build up in the structure because there is little or no cooling load. Thus, the air conditioner is not running enough to remove the excess moisture being brought in. Use a control system that in some way can control the system based on occupancy.

IMPORTANT
Operating the ERV-F during unoccupied periods can result in a buildup of moisture in the structure.

Recommended Control Sequences
Several possible control scenarios are listed below:

1. Use a programmable electronic thermostat with auxiliary terminal to control the ERV-F based on daily programmed occupancy periods. Bard markets and recommends Bard Part No. 8403060 programmable electronic thermostat for air conditioner and  heat pump applications.
2. Use a motion sensor in conjunction with a mechanical thermostat to determine occupancy in the structure. Bard recommends Bard Model CS9B*-**** CompleteStat for this application.
3. Use a CO2 control with dry contacts to energize the ERV-F when CO2 levels rise above desired settings.
4. Use a DDC control system to control the ERV-F based on a room occupancy schedule to control the ERV-F.
5. Tie the operation of the ERV-F into the light switch. The lights in a room are usually on only when occupied.
6. Use a manual timer that the occupants turn to energize the ERV-F for a specic number of hours.
7. Use a programmable mechanical timer to energize the ERV-F and indoor blower during occupied periods of the day.

Ventilation Airflow

The ERV-FA and ERV-FC are equipped with a 3-speed motor to provide the capability of adjusting the ventilation rates to the requirements of the specific application by changing motor speeds (see Table 2).

WARNING
Open disconnect to shut all power OFF before changing motor speeds. Failure to do so could result in injury or death due to electrical shock.

The units are set from the factory with the exhaust blower on the low speed and the intake blower on medium speed. Moving the speed taps located in the control panel can change the blower speed of the intake and exhaust (see Figure 6 on page 12).
NOTE: No setup changes required to operate in Balanced ClimateTM mode.

FIGURE 6
Speed Tap Label

TO ADJUST INTAKE AND EXHAUST BLOWER SPEEDS

1. DISCONNECT POWER TO UNIT
2. REMOVE ERV CONTROL PANEL COVER
3. MOVE BLACK INSULATOR TO DESIRED SPEED ON TERMINAL CONNECTOR

Energy Recovery Ventilator Maintenance

General Information
The ability to clean exposed surfaces within air moving systems is an important design consideration for the maintenance of system performance and air quality.
The need for periodic cleaning will be a function of operating schedule, climate and contaminants in the indoor air being exhausted and in the outdoor air being supplied to the building. All components exposed to the airstream, including energy recovery wheels,  may require cleaning in most applications.
Rotary counterfflow heat exchanges (heat wheels) with laminar airflow are “self-cleaning” with respect to dry particles. Smaller particles pass through; larger particles land on the surface and are blown clear as the flow direction is reversed. For this reason, the  primary need for cleaning is to remove films of oil-based aerosols that have condensed on energy transfer surfaces. Buildup of material over time may eventually reduce airflow. Most importantly, in the case of desiccant-coated (enthalpy) wheels, such films can close off micron-sized pores at the surface of the desiccant material, reducing the efficiency with which the desiccant can absorb and desorb moisture.
Frequency
In a reasonably clean indoor environment such as a school, office building or home, experience shows that reductions of airflow or loss of sensible (temperature) effectiveness may not occur for 10 or more years.
However, experience also shows that measurable changes in latent energy (water vapor) transfer can occur in shorter periods of time in commercial, institutional and residential applications experiencing moderate occupant smoking or with cooking facilities.
In applications experiencing unusually high levels of occupant smoking, such as smoking lounges, nightclubs, bars and restaurants, washing of energy transfer surfaces, as frequently as every 6 months, may be necessary to maintain latent transfer efciency.
Similar washing cycles may also be appropriate for industrial applications involving the ventilation of high levels of smoke or oil-based aerosols such as those found in welding or machining operations, for example.
In these applications, latent efficiency losses of as much as 40% or more may develop over a period of 1 to 3 years.
Cleanability and Performance
In order to maintain energy recovery ventilation systems, energy transfer surfaces must be accessible for washing to remove oils, grease, tars and dirt that can impede performance or generate odors. Washing of the desiccant surfaces is required to remove contaminate buildups that can reduce absorption of water molecules. The continued ability of an enthalpy  wheel to transfer latent energy depends upon the  permanence of the bond between the desiccant and the energy transfer surfaces.
Bard wheels feature silica gel desiccant permanently bonded to the heat exchange surface without adhesives; the desiccant will not be lost in the washing process. Proper cleaning of the Bard energy recovery wheel will restore latent effectiveness to near original performance.

Maintenance Procedures
NOTE: Local conditions can vary and affect the required time between routine maintenance procedures; therefore, all sites (or specific units at a site) may not have the same schedule to maintain acceptable performance. The following timetables are  recommended and can be altered based on local experience.
Quarterly Maintenance

1. Inspect mist eliminator/prefilter and clean if necessary. This filter is located in the fresh air intake hood on the front of the unit. This is an aluminum mesh filter and can be cleaned with water and any detergent not harmful to aluminum.

2. Inspect wall-mount unit filter and clean or replace as necessary. This filter is located either in the nit, in a return air filter grille assembly or both.
   If in the unit it can be accessed by removing the lower service door on the front of the unit. If in a return air filter grille, by hinging the grille open to gain access.

3. Inspect energy recovery ventilator for proper wheel rotation and dirt buildup. This can be done in conjunction with Item 2 above. Energize the energy recovery ventilator after inspecting the filter and observe for proper rotation and/or dirt buildup.

4. Recommended energy recovery wheel cleaning procedures follow: Disconnect all power to unit. Remove the lower service door of the wallmount unit to gain access to the energy recovery ventilator.

5. Remove the front access panel on the ventilator.
   Unplug amp connectors to cassette motors. Slide energy recovery cassette out of ventilator.

6. Use a shop vacuum with brush attachment to clean both sides of the energy recovery wheels.

7. Reverse shop vacuum to use as a blower and blow out any residual dry debris from the wheel.
   NOTE: Discoloration and staining of the wheel does not affect its performance. Only excessive buildup of foreign material needs to be removed.

8. If any belt chirping or squealing noise is present, apply a small amount of LPS-1 or equivalent dry film lubricant to the belt.

Annual Maintenance

1. Inspect and conduct the same procedures as outlined under Quarterly Maintenance.

2. To maintain peak latent (moisture) removal capacity, it is recommended that the energy recovery wheels be sprayed with a diluted nonacidbased evaporator coil cleaner or alkaline detergent solution such as 409.
   NOTE: Do not use acid-based cleaners, aromatic solvents, temperatures in excess of 170°F or steam. Damage to the wheel may result.
   Do not disassemble and immerse the entire heat wheel in a soaking solution, as bearing and other damage may result.

3. Rinse wheel thoroughly after application of the cleaning solution and allow to drain before reinstalling.

4. No re-lubrication is required to heat wheel bearings of the drive motor, or to the intake and exhaust blower motors.

5. If any belt chirping or squealing noise is present, apply a small amount of LPS-1 or equivalent dry film lubricant to the belt.
   Figure 8
   Belt Replacement Instructions
   (Two Wheel Cassette Only)
   FIGURE 9
   Hub Assembly with Ball Bearings

Bard Manufacturing Company, Inc.
Bryan, Ohio 43506
www.bardhvac.com

Manual: 2100-701D
Supersedes: 2100-701C
Date: 6-8-23

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