Bard QCRV-4 User manual

Page 1 of 8
INSTALLATION INSTRUCTIONS
Bard Manufacturing Company, Inc.
Bryan, Ohio 43506
www.bardhvac.com
Manual: 2100-764
Supersedes: NEW
Date: 1-19-22
Commercial Room Ventilator
with Exhaust and Optional CO2Modulation
Model: QCRV-4 (920-0540)
For Use with Bard QC501 Series
Chilled Water Air Conditioners

Manual 2100-764
Page 2 of 8
CONTENTS
Description ............................................................3
QCRV-4 ................................................................. 3
Blade Adjustment for Desired Ventilation Air .............4
CRV Board Sequence of Operation............................5
Adding Optional CO2Control Sensor ......................... 6
Figures
Figure 1 Adjusting OCC Potentiometer on CRV
Control Board. ...................................... 3
Figure 2 CRV Installation and Adjustment ............ 4
Figure 3 CRV Control Board ................................5
Figure 4 CRV Wiring Diagram ..............................7
Figure 5 8403-096 CO2Sensor Set Up................8
Table
Table 1 QCRV-4 Ventilation Mode.......................5

Manual 2100-764
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Description
The QCRV commercial room ventilator (CRV) is
designed to be used with Bard QC501 series chilled
water air conditioners. It is an electromechanical
ventilation system designed to provide fresh air to
meet indoor air quality standards with built in exhaust
provisions.
FIGURE 1
Adjusting OCC Potentiometer on CRV Control Board
QCRV-4
The QCRV-4 has a spring return damper blade. If vent
operation is no longer required or in the event of a
power loss, the blade will spring return close. Adjusting
the OCC potentiometer on the CRV control board will set
the maximum blade position (see Figure 1) Using the
graphs, set the blade position to deliver the proper CFM.
Adjust blade using the
OCC potentiometer.
MIS-4363

Manual 2100-764
Page 4 of 8
MIS-4360 A
CRV MOUNTING HOLES
USE POTENTIOMETERS ON
CRV BOARD TO ADJUST
THE BLADE POSITION IN
EACH MODE OF OPERATION
Blade Adjustment for Desired
Ventilator Air
NOTE: QCRV-4 is factory adjusted to the "B" blade
setting.
The amount of ventilation air supplied by the
commercial room ventilator is dependent on ve (5)
factors:
1. Return air pressure drop.
2. Supply air duct static pressure drop.
3. Indoor blower motor speed.
4. Damper blade open position setting for each mode
of operation.
5. Tightness or looseness of building envelope.
To determine the amount of fresh air that will be
supplied to the structure:
1. Determine the pressure drop of the supply air duct
(see Table 1). For duct-free applications with return
air lter grille and supply grille, use the Duct-Free
column.
2. Determine the ventilation CFM required.
3. Find the ventilation CFM required in Table 1. Read
left to determine required blade position for the
desired ventilation CFM.
FIGURE 2
CRV Installation and Adjustment

Manual 2100-764
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4. Energize ventilator and adjust OCC potentiometer
to open the blade to the desired position on the
QCRV-4 (see Figure 1 on page 3). Label on right
side of QCRV indicates the A, B, C, D and E
positions. Remove lter for better viewing.
5. Program thermostat, CS2000A or DDC control
system to turn on ventilator during occupied
periods only.
CRV Board Sequence of Operation
The “V” Ventilation option includes a control board with
blade positioning potentiometers along with an input
for a 2-10V input signal (see Figure 3).
Adjustable potentiometers:
“PP” Potentiometer setting: This potentiometer can be
used to adjust the blade setting for outdoor air intake
during a pre-purge cycle. The pre-purge cycle time is
based on the setting of the pre-purge timer. The pre-
purge time can be set to 0, 30, 60 or 90 minutes using
the PP jumper on the CRV control board. The pre-purge
function is triggered when the "3" terminal on the low
voltage terminal strip is energized, indicating occupancy.
Once the selected time has passed, the blade will move
to the position set by the "OCC" potentiometer.
“OCC” Potentiometer setting: This potentiometer can
be used to adjust the blade setting for outdoor air
intake when the "3" terminal is energized on the low
voltage terminal strip indicating occupancy. The control
board will energize the occupied setting after the pre-
purge cycle or immediately if pre-purge jumper is set to
the "0" position.
MIS-4362 A
WHEN Y2 IS ENERGIZED
Y1 WILL OVERRIDE OCC
30
SETTING FOR 2ND STAGE
60
90
TURN OFF FOR C02
COOLING OR BLADE POSITION
FULL MODULATION
PRE-PURGE
TIMER
POT "Y1" SETTING FOR
STAGE ONE COOLING
POT "OCC" OCCUPIED SETTING
POT "PP" PRE-PURGE
SET FOR PREOCCUPANCY
0
POT "Y1" SETTING --
NOTAPPLICABLE ON
THIS MODEL
POT "Y2" SETTING --
NOTAPPLICABLE ON
THIS MODEL
POT "OCC" OCCUPIED SETTING
-- TURN OFF FOR CO2 FULL
MODULATION
PRE-PURGE TIMER
POT "PP" PRE-PURGE --
SET FOR PREOCCUPANCY
TABLE 1
QCRV-4 Ventilation Mode
Damper
Position Duct-Free
Static Pressure
0.1 0.3 0.5
A 140 135 125 120
B 180 170 160 160
C 220 210 205 195
D 315 315 315 290
E 410 400 385 380
FIGURE 3
CRV Control Board

Manual 2100-764
Page 6 of 8
“Y1” Potentiometer setting: Not applicable on this
model.
“Y2” Potentiometer setting: Not applicable on this
model.
2-10V Operation
A CO2sensor or other device sending a 2-10V signal
can be used to control the damper motor. Two control
methods are available to control the damper motor:
• Method 1: The control board will accept a
2-10VDC signal with a resistive load greater than
5000 ohms. Bard CO2sensor part #8403-096 can
be used when the 2-10V output is connected to
the "CO2 V IN" tab on the CRV control board. The
pre-purge "PP" and occupied "OCC" potentiometer
settings must be set to the off position and pre-
purge jumper must be set to "0" position for total
modulation. The OCC potentiometer can be used
to maintain a minimum blade position when "3" is
energized.
• Method 2: The damper motor will accept a
2-10VDC signal with a resistive load less than
5000 ohms. This method involves bypassing the
control board and powering the motor directly from
the device providing the 2-10VDC modulating
signal. The 1/4" tab connector of the white wire
coming from the damper motor lead must be
disconnected from the CRV control board wiring.
The 2-10V signal coming from the CO2controller
must be connected to this wire.
During 2-10VDC operation with "3" energized and
pre-purge timed operation active, DC voltage signaling
occupancy from a source such as a CO2sensor will
increase ventilation amounts as needed.
Adding Optional Co2Control Sensor
Adding an optional CO
2
control sensor (Bard Part
#8403-096) to this control will maximize the
capabilities of this vent by only supplying fresh air intake
to maintain CO
2
levels. This has multiple benets.
• Minimizes ventilation load on structure as it only
brings in what is required to maintain CO2levels
thus lowering reconditioning requirements (not
having to heat/cool as much outside air).
• Will self-adjust for various occupancy levels so
that fresh air is not being brought in beyond need.
For example, if a room is designed for a maximum
occupancy of 40 persons (standard ventilation
control would have to be set for that occupancy),
but the room typically only contains 25 persons.
This control will self-adjust the amount of fresh air
intake from 600 to 375 CFM automatically (based
upon 15 CFM per person standard rate to ASHRAE
standards).
Basic Installation
1. Make sure power is turned off to the unit
2. Run four (4) wire thermostat wire from the unit to
the desired CO2sensor location.
3. Follow Figure 5 on page 8 to congure the CO2
sensor for proper operation.
4. Connect the thermostat wiring from the CO
2
sensor
to step control assembly following the wiring diagram
in Figure 4 or the one on the ventilator assembly.
5. To check operation, restore power to the unit.
6. Make sure that thermostatic control is in
“occupied” mode of operation calling for
ventilation. Terminal “3” on the low voltage
terminal strip must be energized to open damper.
7. Have someone stand in front of the CO2sensor
and breathe on it. The display should show an
increase in CO2ppm, and the damper blade in the
ventilation package should increase. (It may be
best to have two people to do this—one to breathe
on control and one to observe damper.)

Manual 2100-764
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FIGURE 4
CRV Wiring Diagram
2
6
5
4
3
1
FDBK
4056-265 A
BROWN
3 PIN
BROWN/WHITE
RED
VENT PLUG
25
Actuator Motor
BROWN/WHITE
2
BLACK
P3-3 P3-2 P3-1
OPTIONAL CO2 CONTROL
REQUIRED FIELD WIRING FOR
1
*B - ON/OFF CO2 CONTROL
*Unused - Tape off
3
TERMINAL STRIP
*A *B
CRV CONTROL BOARD
UNIT LOW -VOLT
*B
SETTING)
KEY
RED/WHITE
24V
(USING OCC POTENTIOMETER
C
BLACK/WHITE
*A - MODULATING CO2 CONTROL
COM
Control
WHITE
3
24
RCO2
(8403-096)
60
30
90
0

Manual 2100-764
Page 8 of 8
FIGURE 5
8403-096 CO2Sensor Set Up
ON
OFFOFFOFF
ON
4 65
23
ON
1
PRESS UP AND DOWN
ARROWS TO ENTER
CONFIGURATION MODE
USE ARROWS TO SELECT
SETTING. PUSH MIDDLE
BUTTON TO CHANGE.
CONTROLLER WILL
SHOW SET.
IT HAS BEEN CONFIGURED.
DIP SWITCH TO "OFF" AFTER
CONTROLLER MOVE
NOTE: MENU
DIP SWITCH MUST
BE IN "ON" POSITION #5
TO CHANGE ANY
SETTINGS WITH
THE SIDE BUTTONS.
TO LOCK THE CO2
DIP SWITCHES MUST BE
POSITIONED AS SHOWN
FOR PROPER OPERATION MIS-4025 C
Settings Recommended Default
RON
(RELAY ON SET POINT) 725
ROF
(RELAY OFF SET POINT) 700
DSP
(DISPLAY
CONFIGURATION) C CT
UNI
(UNITS SELECTION) US US
COL
(CO2 LOW OUTPUT
RANGE) 700 0
COH
(CO2 HIGH OUTPUT
RANGE) 1500 2000
TOL
(TEMP. LOW OUTPUT
RANGE) Not Used
TOH
(TEMP. HIGH OUTPUT
RANGE) Not Used
BAR
(BAROMETRIC
PRESSURE)
See Instructions with
Controller For High
Altitude Installations
CAL
(CALIBRATION) Used for Field Calibration