Manual 7960-860A
Page
2 of 6
Installation
1. Disconnect all power to the unit.
2. Remove outer and inner control panel covers, upper
front panel and right-side condenser inlet grille.
3. Mount 910-2011 relay assembly to control panel
as shown in Figure 1 on page 3. Use phillips head
screws included with kit to attach relay to control
panel.
4. 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-to-
point.
NOTE:
If this kit is being installed together with the
outdoor thermostat kit, use the relay assembly
supplied with the thermostat kit. Only the solid
black wire and the multiplier will need used
from the relay assembly in this kit.
5. Locate black wire from the relay assembly and
route through cable duct to defrost control logic
board (see Figure 1). Before connecting this black
wire to the NC fan relay contact on the defrost
logic control board, remove wire that is currently
connected there (on 230V models, it’s the black
outdoor fan motor lead; on 460V models, red/black
wire) and connect that wire to Terminal 3 on the
installed relay.
6. Locate black/white wire from relay assembly and
route through cable duct to defrost control logic
board. Connect black/white wire to C terminal. If
the heat pump is a dehum unit, remove the black/
white wire already connected to the C terminal and
stack it back onto the black/white wire from the
relay assembly.
7. Locate blue wire from relay assembly and route
through cable duct to defrost control logic board.
Connect blue wire to B terminal. Remove blue wire
already connected to B terminal and stack it back
onto the blue wire from the relay assembly.
8. A service port is located on the refrigerant liquid
line just above the liquid line filter drier (mounted
to the outdoor fan shroud). This port is intended
for the application of 8406-105 low ambient fan
cycling switch (see Figure 2 on page 4). Remove
the service cap from this service port and quickly
thread the low ambient fan cycling switch onto
this port. Once snug, use two wrenches to tighten
the switch an additional 1/4 turn (one to hold
the service port and one on the switch). Use soap
bubbles to confirm the seal is completely tight on
this connection.
9. Install outdoor temperature switch assembly to the
fan shroud and route the wires to the control panel
as shown in Figure 2. This switch defeats Balanced
Climate airflow whenthe temperature falls below
50°F to help prevent evaporator freeze up. Refer to
the unit installation manual for more information
on Balanced Climate operation.
10. Install freeze protect thermostat to the evaporator
coil as shown in Figure 3 on page 5. Route the
wires down through the copper bushing and into
the control panel with the blower motor wires.
11. Route the two black leads from the low ambient
fan cycling switch up into the control panel with
the other wires from this compartment, taking
care to route and secure the wires. Use cable
ties included with kit. Route the two black wires
into the cable duct and then out the side of
the cable duct towards the installed 910-2011
relay. Connect these two wires to Terminal 1 and
Terminal 3 of the relay (see Figure 4 on page 6).
12. Find the purple wire not connected to anything
that is tucked in the cable duct (see Figure 1).
Pull it out and connect it to the end of the outdoor
temp switch wire that has an insulated 1/4" quick
connect. Connect the other end of the outdoor
temperature switch to the Y terminal on the defrost
logic board for 1-phase units or on the phase
monitor for 3-phase units. Refer to Figures 1 and 4
and the unit wiring diagram.
13. Connect the freeze protect thermostat wires in
line with the “Y” input signal to the defrost logic
control.
For 1-phase units, connect the end with the 1/4"
quick connect to Y terminal on the defrost logic
control. Connect the other end with the 1/4" tab to
the yellow/white wire coming from the low voltage
terminal strip or to the orange/black wire coming
from the low ambient bypass relay (if equipped)
or to the yellow/black wire in units equipped with
mechanical dehumidification. Refer to the unit
wiring diagram.
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 defrost logic control.
14. Recheck wiring by referring to unit wiring diagram.
15. Apply “This unit equipped with CMH-34 control
module” label to the inside of the inner control
panel cover above the wiring diagram.
16. Replace all panels and covers. This completes the
installation.
17. Turn on power to unit. Check for proper operation
of the unit by referring to
Sequence of
Operation
.
