Bard 920-0074 QWSERV User manual

Manual 2100-533A
Page 1 of 12
OPERATION INSTRUCTIONS
Model: 920-0074
QWSERV
ENERGY RECOVERY VENTILATOR
WITH EXHAUST
For Use With Bard
2 Through 5 Ton
QW*S Series
Bard Manufacturing Company, Inc.
Bryan, Ohio 43506
Since 1914...Moving ahead, just as planned.
Manual: 2100-533A
Supersedes: 2100-533
File: Volume II, Tab 14
Date: 12-08-10

Manual 2100-533A
Page 2 of 12
CONTENTS
Electrical Specifications .......................................... 3
General Description of ERV ................................... 3
Control Requirements ............................................ 3
Recommended Control Sequences ....................... 4
Control Wiring ........................................................ 4
Ventilation Airflow ................................................... 4
Performance & Application Data ............................ 5
Energy Recovery Ventilator Maintenance ........ 6 & 7
Maintenance Procedures ....................................... 7
Figures
Figure 1 Blower Speed Adjustment ....................... 4
Figure 2 Belt Replacement .................................... 8
Figure 3 Hub Assembly with Ball Bearings ............ 9
Figure 4 Disconnect & Tape Off Wiring ................ 11
Figure 5 Field Set CO
2
Sensor Jumpers .............. 12
Wiring Diagram
.............................................................. 10
Tables
Table 1 Ventilation Air (CFM) ................................ 4
Table 2 Summer Cooling Performance ................ 5
Table 3 Winter Heating Performance ................... 6
COPYRIGHT DECEMBER 2009
BARD MANUFACTURING COMPANY, INC.
BRYAN, OHIO USA 43506

Manual 2100-533A
Page 3 of 12
GENERAL DESCRIPTION
The Energy Recovery Ventilator was designed to
provide energy efficient, cost effective ventilation to
meet I. A. Q. (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 CO
2
, smoke,
radon, formaldehyde, excess moisture, virus and
bacteria.
The ventilator incorporates patented rotary heat
exchange state-of-the-art technology to remove both
heat & moisture and provides required ventilation to
meet the requirements of ASHRAE 62.1 standard.
It is designed as a single package which is factory
installed. The package consists of a unique rotary
Energy Recovery Cassette that can be easily removed
for cleaning or maintenance. It has two 15-inch
diameter heat transfer wheels for efficient heat transfer.
The heat transfer wheels use a permanently bonded dry
desiccant coating for total heat recovery.
Ventilation is accomplished with 2 blower/motor
assemblies each consisting of a drive motor and dual
blowers for maximum ventilation at low sound levels.
Motor speeds can be adjusted so that air is exhausted at
the same rate that fresh air is brought into the structure
thus not pressuring the building. The rotating energy
wheels provide the heat transfer effectively during both
summer and winter conditions.
NOTE: Operation is not recommended below 5°F
outdoor temperature because freezing of
moisture in the heat transfer wheel can occur.
CONTROL REQUIREMENTS
1. Indoor blower motor must be run whenever the ERV
is run.
2. Select the correct motor speed on the ERV. Using
Table 1 of the ERV Installation Instructions
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 if only 200
CFM of ventilation air is needed. Use the low speed
tap. Using the high speed tap would serve no useful
purpose and would effect the overall efficiency of the
air conditioning system. System operation costs
would also increase.
3. Run the ERV only during periods when the
conditioned space is occupied. Running the ERV
during unoccupied periods wastes energy, decreases
the expected life of the ERV, and can result in a large
moisture buildup in the structure. The ERV can
remove up to 60 to 70% of the moisture in the
incoming air, not 100% of it. Running the ERV
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.
NOTE: The Energy Recovery Ventilator is NOT a
dehumidifier.
ELECTRICAL SPECIFICATIONS
ledoMegatloVspmA lortnoC egatloV
4700-029802/0322.2V42
ledoM ehthtiwesUroF stinUgniwolloF
4700-029
C-,B-,A-S2WQ C-,B-,A-S3WQ C-,B-,A-S4WQ C-,B-,A-S5WQ
IMPORTANT
Operating the ERV during unoccupied periods
can result in a build up of moisture in the
classroom.

Manual 2100-533A
Page 4 of 12
The ERV units are wired from the factory on medium
intake and low exhaust speeds. The ERV is equipped
with independently controlled 3-speed motor to provide
the capability of adjusting the ventilation rates to the
requirements of the specific application and to be able to
provide positive pressure in the structure. This is
accomplished by setting the intake blower on a higher
speed than the exhaust blower.
RECOMMENDED CONTROL
SEQUENCES
Several possible control scenarios are listed below:
1. Use a programmable electronic thermostat with
auxiliary terminal to control the ERV based on daily
programmed occupancy periods. Bard markets and
recommends Bard Part No. 8403-060 programmable
electronic thermostat for heat pump applications.
2. Use a motion sensor in conjunction with a
mechanical thermostat to determine occupancy in
the classroom. Bard markets the CS2000A for this
use.
3. Use a DDC control system to control the ERV based
on a room occupancy schedule.
4. Tie the operation of the ERV into the light switch.
The lights in a room are usually on only when
occupied.
5. Use a manual timer that the occupants turn to
energize the ERV for a specific number of hours.
6. Use a programmable mechanical timer to energize
the ERV and indoor blower during occupied periods
of the day.
7. Use Bard Part No. 8403-056 CO
2
controller for “on-
demand” ventilation.
CONTROL WIRING
The QWSERV comes wired in the low voltage control
circuit from the factory.
With the “X” Remote Thermostat Option, it is default
wired into the “A” terminal, which drives the vent to
operate only during occupied periods when using a Bard
8403-060 thermostat or Bard CS2000 controller. If you
prefer for the QWSERV to operate anytime the blower
is operational, you will need to install a jumper wire
from “G” to “A”. If you prefer to use Bard 8403-056
CO
2
controller to make the ventilation “on-demand”,
there is a connection adjacent to the thermostat
connections in the unit upper right-hand corner, and is
marked to match CO
2
controller connections.
Furthermore, disconnect and tape off the wire as shown
in Figure 4 and you will need to field set the CO
2
sensor
jumpers per Figure 5.
With the “D” Door Mounted Thermostat Option, the
thermostat is already connected and programmed to
operate the QWSERV only during occupied periods.
With the “H” Door Mounted Thermostat and CO
2
controller, the unit is ready to go with “on-demand”
ventilation as controlled by the CO
2
controller.
VENTILATION AIRFLOW
The ERV is equipped with a 3-speed motor to provide
the capability of adjusting the ventilation rates to the
requirements of the specific application by simply
changing motor speeds.
TABLE 1
VENTILATION AIR (CFM)
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MFC 054573003
WARNING
Open disconnect to shut all power OFF before
doing this. Failure to do so could result in injury
or death due to electrical shock.
FIGURE 1
BLOWER SPEED ADJUSTMENT
Moving the speed taps located in the control panel can
change the blower speed of the intake and exhaust. See
Figure 1.

Manual 2100-533A
Page 5 of 12
PERFORMANCE AND APPLICATION DATA
TABLE 2
SUMMER COOLING PERFORMANCE
(INDOOR DESIGN CONDITIONS 75° DB / 62° WB)
LEGEND
VLT = Ventilation Load – Total HRT = Heat Recovery – Total
VLS = Ventilation Load – Sensible HRS = Heat Recovery – Sensible
VLL = Ventilation Load – Latent HRL = Heat Recovery – Latent
tneibmA
.D.O
MFC054–ETARNOITALITNEV
ycneiciffE%56
MFC573–ETARNOITALITNEV
ycneiciffE%66
MFC003–ETARNOITALITNEV
ycneiciffE%76
BW/BD
FseergeDTLVSLVLLVTRHSRHLRHTLVSLVLLVTRHSRHLRHTLVSLVLLVTRHSRHLRH
501 570756
56412 08541 08541 08541 08541 08541 4886 0
0
25931 7749 7749 7749 7749 7749 5744 0
0
78871 05121 05121 05121 05121 05121 7375 0
0
50811 8108 8108 8108 8108 8108 6873 0
0
01341 0279 0279 0279 0279 0279 0954 0
0
7859 2156 2156 2156 2156 2156 5703 0
0
001
0857075606 09513 56412 25321 05121 05121 05121 05121 05121 05121 05121 04491 4139 202 0
0
33502 25931 9208 7987 7987 7987 7987 7987 7987 7987 53621 4506 131 0
0
52362 78871 39201 52101 52101 52101 52101 52101 52101 52101 00261 2677 861 0
0
47371 50811 3976 2866 2866 2866 2866 2866 2866 2866 29601 3215 111 0
0
06012 01341 5328 0018 0018 0018 0018 0018 0018 0018 06921 0126 531 0
0
01141 7859 7155 7245 7245 7245 7245 7245 7245 7245 3868 0614 090
0
59
0857075606 09513 56412 25321 0279 0279 0279 0279 0279 0279 0279 07812 44711 2362 0
0
33502 25931 9208 8136 8136 8136 8136 8136 8136 8136 51241 4367 1171 0
0
52362 78871 39201 0018 0018 0018 0018 0018 0018 0018 52281 7879 3912 0
0
47371 50811 3976 5435 5435 5435 5435 5435 5435 5435 82021 9546 7441 0
0
06012 01341 5328 0846 0846 0846 0846 0846 0846 0846 08541 0387 5571 0
0
01141 7859 7155 1434 1434 1434 1434 1434 1434 1434 8679 6425 5711 0
0
09
0857075606 09513 56412 25321 0927 0927 0927 0927 0927 0927 0927 00342 57141 2605 0
0
33502 25931 9208 8374 8374 8374 8374 8374 8374 8374 49751 3129 0923 0
0
52362 78871 39201 5706 5706 5706 5706 5706 5706 5706 05202 21811 8124 0
0
47371 50811 3976 9004 9004 9004 9004 9004 9004 9004 56331 6977 4872 0
0
06012 01341 5328 0684 0684 0684 0684 0684 0684 0684 00261 0549 5733 0
0
01141 7859 7155 6523 6523 6523 6523 6523 6523 6523 45801
1
336
1
622 0
0
58
0857075606 09513 56412 25321 0684 0684 0684 0684 0684 0684 0684 03762 50661 2947 0
0
33502 25931 9208 9513 9513 9513 9513 9513 9513 9513 47371 39701 0784 0
0
52362 78871 39201 0504 0504 0504 0504 0504 0504 0504 57222 73831 3426 0
0
47371 50811 3976 2762 2762 2762 2762 2762 2762 2762 10741 2319 0214 0
0
06012 01341 5328 0423 0423 0423 0423 0423 0423 0423 02871 07011 5994 0
0
01141 7589 7155 0712 0712 0712 0712 0712 0712 0712 93911 6147 6433 0
0
08
57075606 56412 25321 2524 0342 0342 0342 0342 0342 53091 2299 2281 0 25931 9208 4672 9751 9751 9751 9751 9751 27321 9446 4811 0 78871 39201 3453 5202 5202 5202 5202 5202 26851 8628 8151 0 50811 3976 8332 6331 6331 6331 6331 6331 96401 7545 2001 0 01341 5328 5382 0261 0261 0261 0261 0261 09621 5166 5121 0 7859 7155 9981 5801 5801 5801 5801 5801 2058 2344 418 0
57 075606
25321 2524 0 0
0
0
25321 2524 0 9208 4672 0 0
0
0
9208 4672 0 39201 3453 0 0
0
0
39201 3453 0 3976 8332 0 0
0
0
3976 8332 0 5328 5382 0 0
0
0
5328 5382 0 7155 9981 0 0
0
0
7155 9981 0

Manual 2100-533A
Page 6 of 12
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 counterflow heat exchangers (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 blow 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 adsorb 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 ten 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 six months, may be
necessary to maintain latent transfer efficiency. 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 one to three years.
NOTE:Sensible
performance only
is shown for
winter application.
TABLE 3
WINTER HEATING PERFORMANCE — (INDOOR DESIGN CONDITIONS 70°F DB)
tneibmA
.D.OETARNOITALITNEV
BD
FseergeD
.ffE%08MFC054.ffE%18MFC573.ffE%28MFC003
TLVSRHSLVTLVSRHSLVTLVSRHSLV
56034244916845202046158302618231292
06068488832790504082307704236562385
5509272385854157060294451106845893578
05027967774491001816569351084631356611
5405121027903425210110284291001824668541
04085414661161920512114899032027907970571
5301071806312043571411841139620431189291402
03044912555188830026122131870306921726013332
52078126947147345228126741364308541559114262
02003420449106840520220461848300261482316192
51037624831264355722224081232402871216418023
01061928233223850034238691716404491149519943
5095132725281365236232312200506012962711973
0020436127240860538246922783508622895812804
5-054630619209275730340642177500342629914734
01-088834011367770042344262651602952452126664
LEGEND
VLT = Ventilation Load – Total HRS = Heat Recovery – Sensible VLS = Ventilation Load – Sensible

Manual 2100-533A
Page 7 of 12
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 adsorption 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 wall sleeve
and can be accessed by either removing the exterior
louver grille, the vent package from inside the unit,
or by disconnecting the unit from the wall brackets,
and rolling the unit away from the sleeve on its
integral wheel system. The filter is an aluminum
mesh filter and can be cleaned with water and any
detergent not harmful to aluminum.
2. Inspect the comfort air filter and clean or replace as
necessary. This filter is located behind the front-
hinged service door.
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 the unit.
Open the front-hinged service door to the unit.
5. Remove the front cassette retaining panel from the
front of the ERV. Unplug the amp connectors to the
cassette drive motor. Slide energy recovery cassette
out of the 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 nonacid
based 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.

Manual 2100-533A
Page 8 of 12
FIGURE 2
BELT REPLACEMENT INSTRUCTIONS
Belt Replacement
Instructions
MIS-2166
Route (1) replacement belt
in bottom groove of pulley.
Route (1) replacement belt
in top groove of pulley.
If belts "squeak" or "chirp"
lubricate lightly with LPS-1
or equivalent "dry film"
lubricant.

Manual 2100-533A
Page 9 of 12
FIGURE 3
HUB ASSEMBLY WITH BALL BEARINGS

Manual 2100-533A
Page 10 of 12
21 3456789101112
21
3
208
120 V
480
240
COM
24
2
4
3
1
Control Relay
Damper
Motor
27
3
Motor
12
26
1
Cassette
Motor
25
Motor Plug
Intake
28
28 28
26
CO2 Disconnect
2
25
25 25 25
28
23
28
23 23
26
26
2134567891011
26
Intake
Damper
4
Blk/Red
Black/White
White
Black (High Speed)
Red (Low Speed)
Capacitor
Blue (Med. Speed)
Blue (Med. Speed) Black (High Speed)
Capacitor
Yellow
Intake
Motor Plug
Block
Black
Black
White
Power Plug
1
2 3 4
White
Brown Black Brown
Capacitor
Green
Transformer
Term.
Relay
Black Black
Red
Red
Black/White
Brown/White
Green
Red (Low Speed)
Intake
Capacitor
Exhaust
Motor Plug
Brown/White
Green
Control
Motor Plug
Cassette
for Wiring Energy Recovery to Unit
4114-100
321
4
2
120 V
3
Yellow
2
Speed
Speed Plug
Motor
Capacitor
Capacitor
4 3
Note: See ControlWiring Section of Installation Inst. for Wiring EnergyRecovery to Unit
Note: See ControlWiring Section of Installation Inst.
1
2
Blower
Motor
Cassette
Speed Plug Exhaust Relay
Cassette
Motor Plug
Control
4 1
Motor Plug
Transformer
Power Plug
Intake
Motor
Com
208V
Cassette
Exhaust
Motor
3
Exhaust
Blower
Ground
To Unit High Voltage 240/208-60-1
Blower
SERVICING.
DANGER
Black/White
*DISCONNECT POWER BEFORE *ELECTRICAL SHOCK HAZARD
USE COPPER CONDUCTORS
Motor Plug
480V
Orange
Orange
Black
Black/White
Red
Brown/White
Red/White
75° C.
!
WARNING
ONLY SUITABLE FOR AT LEAST
Brwn/White
Black/White
WIRE FOR 208V OPERATION
White Motor
Black
!
Control Plug
2
TERMINAL BLOCK AND CONNECT RED DISCONNECT ORANGE WIRE FROM CO2 SENSOR IS USED
2
DISCONNECT WHEN
1
Motor Plug
Exhaust
Exhaust
Motor Plug
Plug
Intake
Blower
Speed Plug
1 4
Exhaust
1
2
Intake
Intake
Brown/White
29
Component Capacitor
Blower Motor 4/370 Cassette Motor 3/250

Manual 2100-533A
Page 11 of 12
FIGURE 4
DISCONNECT & TAPE OFF WIRE
DISCONNECT AND TAPE OFF FOR
CO2 CONTROLLED VENTILATION
MIS-2759

Manual 2100-533A
Page 12 of 12
FIGURE 5
FIELD SET CO
2
SENSOR JUMPERS
"AN" SET TO VOLTAGE"SW2" SET TO ON
"OUT" SET TO 20-100%
AN
OFF
ON
ON
OFF
0-100%
20-100%
VOLTAGE
CURRENT
OUTSW2SW1
"SW1" SET TO ON
MIS-2756
QWSERV VENT PACKAGE
CO2CONTROLLER SETTING FOR 1000 PPM