Installation Guide
6
G
RW2
C
E
O
Y
Thermostat
Green
Red
White
G
R
Black
O
Y1 IN
R
C
Air Handler
Heat Pump 
(OD Section)
C
W
W2 OUT
W2 IN
Figure 4. Typical Thermostat  Connections
• Optionalequipmentrequiringconnectiontothepower
or control circuits must be wired in strict accordance 
of the NEC (ANSI/NFPA 70), applicable local codes, 
and the instructions provided with the equipment.
Grounding
 WARNING:
The unit cabinet must have an uninterrupted or 
unbroken electrical ground to minimize personal 
injury if an electrical fault should occur. Do not 
use gas piping as an electrical ground!
This unit must be electrically grounded in accordance 
with local codes or, in the absence of local codes, with 
the National Electrical Code (ANSI/NFPA 70) or the CSA 
C22.1 Electrical Code. Use the grounding lug provided in 
the control box for grounding the unit.
Thermostat/LowVoltageConnections
• Thermostatconnectionsshouldbemadeinaccordance
with the instructions supplied with the thermostat and 
the indoor equipment. A typical installation with a heat 
pump thermostat and air handler is shown in Figure 4.
• Theoutdoorunitisdesignedtooperatefroma24VAC
Class II control circuit. The control circuit wiring must 
comply with the current provisions of the NEC (ANSI/
NFPA 70) and with applicable local codes having 
jurisdiction.
• Thelowvoltagewiresmustbeproperlyconnectedto
the units low voltage terminal block. Recommended 
wire gauge and wire lengths for typical thermostat 
connections are listed in Table 2.
• The thermostat should be mounted about 5 feet
above the floor on an inside wall. DO NOT install the 
thermostat on an outside wall or any other location 
where its operation may be adversely affected by radiant 
heat from fireplaces, sunlight, or lighting fixtures, and 
convective heat from warm air registers or electrical 
appliances. Refer to the thermostat manufacturer’s 
instruction sheet for detailed mounting and installation 
information.
CoreSense
TM
 Diagnostics Module
(Select Models Only)
The CoreSense
TM
 Diagnostics Module, Figure 5 (page 
6), is a breakthrough innovation for troubleshooting 
heat pump and air conditioning system failures. The module 
installs easily in the electrical box of the outdoor unit 
near the compressor contactor.By using the compressor 
as a sensor, CoreSense Diagnostics helps the service 
technician more accurately troubleshoot system and 
compressor fault conditions.
A flashing LED indicator communicates the ALERT code 
and a diagnostic key is also imprinted on the side of the 
module to quickly direct the technician to the root cause 
of a problem. Alert identification codes are also listed in 
Table 3 (page 7).
Table 2. Thermostat Wire
THERMOSTAT
WIRE GAUGE
MAXIMUM RECOMMENDED
THERMOSTAT WIRE LENGTH (FT)
24 25
22 45
20 70
18 110
Figure 5. CoreSense
TM
 Diagnostics Module
Compressor
Common Wire
Reset Button
Tr ip / Lock
(Red LED)
Run / Alert
(Yellow LED)










