Page 1 of 9
Bard Manufacturing Company, Inc.
Bryan, Ohio 43506
www.bardhvac.com
Manual: 7960-848B
Supersedes: 7960-848A
Date: 12-9-19
The CMA-39 is a field-installable low ambient fan cycling
control kit. This low ambient control is only for use on
R-410A refrigerant systems. The low ambient control
pressure sensor is attached to the suction line of the sys-
tem, and monitors low side system pressure. Operation
of the LAC occurs as outdoor temperatures drop below
the 65°F to 50°F range. On/Off LAC operation cycles the
condenser fan operation based on outdoor temperature.
The CMA-39 kit is for use with Bard models W12AB,
W30AB, W30LB, W36AB, W36LB, W42AC, W48AC,
W60AC, W72AC, W3SAC, W4SAC and W5SAC wall-
mount air conditioners.
The CMA-39 kit consists of:
• 7960-848 Installation Instructions
• 8406-112 Low Ambient Fan Cycling Control
• 910-2058 Outdoor Temperature Switch Assembly
• 8408-048 Freeze Protect Thermostat
• 1012-066 3/4" Screw (1)
• 8607-017 Terminal Block
• 1012-085 1/2" Self-Tapping Screws (2)
• 7961-312-0482 CMA-39 Unit I.D. Label
Field-supplied tools needed:
• Personal protection equipment, including gloves
and safety glasses
• 5/16" nut driver
• 1/2" wrench (service port) and 9/16" wrench (LAC
control)
• Phillips head screwdriver
• Small flat head screwdriver for securing wire in
terminal block
CMA-39 Low Ambient Fan Cycling Control
SUPPLEMENTAL INSTRUCTIONS
Sharp metallic edges.
Take care and wear appropriate protective
devices to avoid accidental contact with
sharp edges.
Failure to do so can result in personal
injury.
!
CAUTION
Exposed moving parts.
Disconnect all electrical power before
servicing.
Failure to do so can result in severe injury
or amputation.
!
WARNING
Electrical shock hazard.
Disconnect the remote electric power
supply or supplies before servicing.
Failure to do so can result in serious injury
or death.
!
WARNING
Manual 7960-848B
Page 2 of 12
Installation
1. Disconnect all power to the unit. Remove control
panel inner and outer covers, upper front panel and
right-side condenser inlet grille.
2. Mount supplied 8607-017 terminal block into
control panel with supplied 1012-066 screw as
shown in Figure 1 or Figure 2 (page 4). Terminal
block comes installed in W12 unit; see Figure 3 on
page 5.
3. Disconnect black high voltage outdoor motor
lead from compressor contactor and reconnect
to terminal block that was installed in Step 1 as
shown in Figure 1.
4. Remove the service port cap from the liquid line.
Install the low ambient control (LAC) on the liquid
line by screwing it into the service port. Snug the
connection with wrenches and check for leaks.
See Figure 4 (page 6), Figure 5 (page 7) or Figure
6 (page 8). Route low ambient control wires up
through the bushing in the bottom of the control
panel. Route the wires through the cable duct in
the control panel as shown in Figure 1 or Figure 2.
5. Install outdoor temperature switch assembly to
the fan shroud and route the wires to the control
panel as shown in Figure 4, Figure 5 and Figure 6.
This switch defeats Balanced Climate airflow when
the temperature falls below 50°F to help prevent
evaporator freeze up. Refer to the unit installation
manual for more information on Balanced Climate
operation.
6. Install freeze protect thermostat to the evaporator
coil as shown in Figure 7 (page 9), Figure 8 (page
10) and Figure 9 (page 11). For W12, W30 or W36
units, route the wires down through the copper
bushing and into the control panel with the blower
motor wires. For W42, W48, W60,W72 and W*SAC
units, route the wires down through the bushings in
the blower partition and filter partition beside the
filters and into the control panel.
7. Connect the low ambient control wires to the
terminal block and T2 of the compressor contactor
(see Figure 1, Figure 2 or Figure 3).
8. Find the purple wire not connected to anything
that is tucked in the cable duct (see Figures 1 or
2). Pull it out and connect it to the LAC terminal
block on the terminal that is separate from the
LAC control wire (the purple wire in W12 units
comes connected to the terminal block—see Figure
3). Connect the end of the outdoor temperature
switch that has the insulated quick connect to the
terminal block beside the purple wire. Connect the
other end of the outdoor temperature switch to the
Y terminal on the compressor control module for
1-phase units or on the phase monitor for 3-phase
units. Refer to Figure 10 on page 12 or the unit
wiring diagram.
9. Connect the freeze protect thermostat wires in line
with the “Y” input signal to the compressor control
module (CCM). Refer to the unit wiring diagram.
For 1-phase units, connect the end with the 1/4"
quick connect to Y terminal on the CCM and
the other end with the 1/4" tab to the yellow/
white wire coming from the low voltage terminal
strip or to the yellow/black wire coming from the
dehumidification logic board if unit has mechanical
dehumidification.
For 3-phase units, connect the wire end with
the 1/4" quick connect to “Y out” on the phase
monitor, and the other end with the 1/4" tab to the
yellow/black wire going to the CCM.
10. Recheck wiring by referring to unit wiring diagram.
11. Apply “This unit equipped with CMA-39 control
module” label to the inside of the inner control
panel cover above the wiring diagram.
12. Replace all panels and covers. This completes the
installation.
13. Turn on power to unit. Check for proper operation
of the unit by referring to Sequence of
Operation.
Sequence of Operation
Energize the unit in cooling mode (first or second
stage). The compressor should start (except when
equipped with economizer and enthalpy control is
energizing “free cooling” mode. Energizing Y2 will
override the enthalpy control, allowing the mechanical
cooling to operate). Run the unit for at least 5 minutes.
The condenser fan motor should not run until the
liquid pressure has reached 350 PSI. Should the
liquid pressure fall below 225 PSI while running, the
condenser fan motor will de-energize until the head
pressure builds to 350 PSI.
Manual 7960-848B
Page 3 of 12
MIS-3873 B
ATTACH WIRE
DUCT
FROM FAN MOTOR
BLACK WIRE
CABLE
CONTROL
LOW AMBIENT
LEFT HAND UNITSRIGHT HAND UNITS
FROM FAN MOTOR
BLACK WIRE
CONTACTOR "T2"
FROM COMPRESSOR
REMOVE WIRE
CONTROL
LOW AMBIENT
CONTROL TERM.
TO LOW AMBIENT
AND REPLACE SEALING COMPOUND
CONTACTOR
BLUE WIRE TO
BLACK OR
TERMINAL BLOCK
BROWN WIRE TO
BLACK OR
TERMINAL BLOCK
BROWN WIRE TO
BLACK OR
BLACK OR
ROUTE WIRES THROUGH BUSHING
CONTACTOR
BLUE WIRE TO
TERMINAL
BLOCK
MODULE
CONTROL
COMPRESSOR
COMPRESSOR
CONTACTOR
PHASE
MONITOR
PHASE
MONITOR
FIGURE 1
W30AB, W30LB, W36AB, W36LB
Dashed lines indicate that a wire has been disconnected from this terminal
Manual 7960-848B
Page 4 of 12
FIGURE 2
W42AC, W48AC, W60AC, W72AC, W*SAC
MIS-4055 A
PART #8607-017
COMPRESSOR
PART #1012-066
& SCREW
COMPRESSOR
CONTROL MODULE CONTACTOR
TERMINAL BLOCK
CABLE DUCT
PHASE
MONITOR
Manual 7960-848B
Page 5 of 12
FIGURE 3
W12AB
TERMINAL
CONTROL
LOW AMBIENT
AND REPLACE SEALING COMPOUND
FROM FAN MOTOR
BLACK WIRE
BLACK WIRE TO CONTACTOR
BLACK WIRE TO TERMINAL BLOCK
ROUTE WIRES THROUGH BUSHING
BLOCK
CONTROL TERMINAL BLOCK
TO LOW AMBIENT
ATTATCH WIRE
CONTACTOR "T2"
FROM COMPRESSOR
MODULE
COMPRESSOR
REMOVE WIRE
COMPRESSOR
CONTACTOR
MIS-4132
Manual 7960-848B
Page 6 of 12
FIGURE 4
W30AB, W30LB, W36AB, W36LB
MIS-4056
SCREW
PART #1012-085
RUN WIRES THROUGH THE BUSHING
UP TO THE CONTROL PANEL
LOW AMBIENT CONTROL
PART #8406-112
1/2" WRENCH
9/16" WRENCH
OUTDOOR TEMP
SWITCH ASS'Y
PART #910-2058
Manual 7960-848B
Page 7 of 12
FIGURE 5
W12AB
LOW AMBIENT CONTROL
PART #8406-112
MIS-4131
OUTDOOR TEMP SENSOR PLACEMENT
(2) PLACES
PART #910-2058
NUT
SENSOR ASSEMBLY
FOR EXTRA WIRE LENGTH
OUTDOOR TEMP
PART #1012-210
OUTDOOR TEMP SENSOR
PART #7950-012
(2) PLACES
SCREW
PART #1012-086
PUSH MOUNT CABLE TIE
RUN WIRES UP BUSHING
TO CONTROL PANEL
Manual 7960-848B
Page 8 of 12
FIGURE 6
W42AC, W48AC, W60AC, W72AC, W*SAC
MIS-4057
PART #8406-112
LOW AMBIENT
CONTROL
RUN WIRES UP BUSHING TO CONTROL PANEL
OUTDOOR TEMP SWITCH ASS'Y (YELLOW WIRES)
PART #910-2058
(2) SCREWS
PART #1012-086
Manual 7960-848B
Page 9 of 12
FIGURE 7
W30/W36 Freeze Stat Location and Wire Routing
MIS-4054
USE ONE OF THE MIDDLE
HEADER STUBS TO ATTACH
THE FREEZE STAT TO THE
EVAPORATOR COIL
FREEZE STAT WIRES
RUN DOWN COPPER
THROUGH THE GROMMET
AND INTO THE CONTROL
PANEL WITH THE BLOWER
MOTOR WIRES
Manual 7960-848B
Page 10 of 12
FIGURE 8
W12AB Freeze Stat Location and Wire Routing
MIS-4130
PART #8408-048
TO ADDRESS EXTRA WIRE LENGTH
TO EVAPORATOR COIL.
FREEZE STAT
TO ATTACH FREEZE STAT
USE BOTTOM DISTRIBUTOR TUBE
FREEZE STAT
NOTE: USE PUSH MOUNT CABLE TIE PART #7950-012
ON THE BOTTOM SIDE OF THE BLOWER PARTITION
FREEZE STAT PLACEMENT
WIRES RUN THROUGH
BUSHING AND INOT CONTROL
PANEL WITH THE BLOWER
MOTOER WIRES.
Manual 7960-848B
Page 11 of 12
FIGURE 9
W42/W48/W60/W72/W*SAC Freeze Stat Location and Wire Routing
USE ONE OF THE MIDDLE
HEADER STUBS TO ATTACH
THE FREEZE STAT TO THE
EVAPORATOR COIL.
(BLACK WIRES)
PART #8408-048
FEED WIRES
THRU 1" SNAP
BUSHING GOING
INTO CONTROL
PANEL
FEED WIRES
THRU 1"
BUSHING
MIS-4058
Manual 7960-848B
Page 12 of 12
FIGURE 10
LPC
C
ALR
CC
Y
R
HPC
2
MINUTES
L2
T2
T1
L1
1012 1345678911
Phase Monitor
L2 L3
L1
Y
Yout
C
MIS-4052 B
PHASE
Black
Fan Motor
Purple W24 Units
Switch
Temp
(Behind Low Voltage Block)
12 Pin Plug
Blue on
UNITS
3 PHASE
Low Ambient
W24 Units
MONITOR
Outdoor
Contactor
Compressor
Terminal
Block #2
Control
Module
Compressor
Brown onBlack
Black
Yellow
Yellow
UNITS
Control
Outdoor
1 PHASE
NOTE:
CONNECT YELLOW WIRE FROM
OUTDOOR TEMP SENSOR TO
"Y" TERMINAL ON THE COMPRESSOR
CONTROL MODULE FOR 1-PHASE UNITS,
OR THE "Y" TERMINAL ON THE PHASE
MONITOR FOR 3 PHASE UNITS.
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