Bard CMH-29 Installation instruction
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The CMH-29 is a field-installable combination of low
ambient fan cycling control and a compressor cutout
outdoor thermostat to be used with a Bard wall-
mounted heat pump.
The CMH-29 kit consists of:
• 8406-112 Low Ambient Fan Cycling Switch
• 910-2013 Relay and Compressor Cutout
Thermostat Assembly
• 3/8" vinyl-covered clamps
• Required fasteners
• 7960-771 Installation Instructions
The CMH-29 kit is for use with Bard models W18HA,
W24HA, W30HA and W36HA wall-mount heat pumps.
Compressor Cutout Thermostat
Heat pump compressor operation at outdoor
temperatures below 0° is neither desirable nor
advantageous in terms of efficiency. An outdoor
thermostat can be applied to take the mechanical
heating (compressor) offline, and send the (compressor)
signal to energize electric heat in its place (to make
electric heat first stage heating). This can also be
applied to limit the quantity of available electric heat.
Bard Manufacturing Company, Inc.
Bryan, Ohio 43506
www.bardhvac.com
Manual: 7960-771
Supersedes:
NEW
Date: 4-14-16
CMH-29
Low Ambient Control and
Compressor Cutout Thermostat Kit
For Use with W18HA, W24HA, W30HA and W36HA
Wall-Mount Heat Pumps
INSTALLATION INSTRUCTIONS
Example: Heat pump with 10KW second stage heat.
Once the outdoor thermostat has switched, 15KW
without compressor.
INSTALLATION
1. Disconnect all power to wall-mount unit.
2. Remove outer and inner control panel covers.
3. Remove right side condenser inlet grille.
4. Remove all three front service panels.
5. Mount 910-2013 relay assembly into unit control
panel as shown in Figure 1 on page 3. Use phillips
head screws included with kit to attach relay to
control panel.
6. Remove cover from vertical gray cable duct on
control panel to allow wire harness from installed
relay to route into it (see Figure 1).
NOTE: The unit wiring diagram (included with unit
literature assembly and also located on inner
control panel cover) can be used to wire this
kit. However, the following instructions listed
here provide the necessary connections point-
by-point.