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505331M 06/09
Electrical Connections17
WARNING
Electric shock hazard. Can cause
injury or death.
Line voltage is present at all
components on units with single−pole
contactors, even when unit is not in
operation!
Unit may have multiple power
supplies. Disconnect all remote
electric power supplies before
opening access panel.
Unit must be grounded in accordance
with national and local codes.
In the U.S.A., wiring must conform with current local codes
and the current National Electric Code (NEC). In Canada,
wiring must conform with current local codes and the current
Canadian Electrical Code (CEC).
Refer to the furnace or blower coil installation instructions
for additional wiring application diagrams and refer to unit
nameplate for minimum circuit ampacity and maximum
overcurrent protection size.
230VAC SUPPLY VOLTAGE
The XP19 outdoor unit is rated for 230VAC applications
only. A hard-start kit is required for applications where the
supply voltage is less than 230VAC.
24VAC TRANSFORMER
Use the transformer provided with the furnace or coil
blower for low-voltage control power (24VAC − 40 VA
minimum)
NOTE The addition of accessories to the system could
exceed the 40 VA power requirement of the
factory-provided transformer. Measure the system’s
current and voltage after installation is complete to
determine transformer loading. If loading exceeds the
factory-provided transformer capacity, a larger
field-provided transformer will need to be installed in the
system.
WIRING CONNECTIONS
1. Install line voltage power supply to unit from a properly
sized disconnect switch.
2. Ground unit at unit disconnect switch or to an earth
ground.
NOTE Connect conduit to the unit using a proper
conduit fitting. Units are approved for use only with
copper conductors. A complete unit wiring diagram is
located on the back side of the unit’s access panel.
NOTE For proper voltages, select thermostat wire
gauge per the following chart:
Table 3. Wire Run Length
Wire Run Length
AWG #
Insulation Type
less than 100’ (30m)
18
color−coded, temperature
rating 35
º
C minimum
more than 100’ (30m)
16
3. Install room thermostat (ordered separately) on an
inside wall approximately in the center of the area and
5 feet (1.5 m) from the floor. Do not install on an outside
wall or where sunlight, drafts or vibrations affect it.
4. Install low voltage wiring from outdoor to indoor unit
and from thermostat to indoor unit as illustrated in
Figure 29.
THERMOSTAT SECOND−STAGE COOLING
CONNECTIONS
The Lennox System Operation Monitor (LSOM) requires a
twos−stage room thermostat to operating properly.
S
Y2 Room Thermostat Wire Connect the Y2 room
thermostat wire from the outdoor unit to the Y2 input
on the DCB.
S
L Terminal Wiring Connect L terminal of the room
thermostat to the L (brown) field wire connection.
S
Y2 DC Solenoid Connector (DC SOL) The two−pin
DC solenoid connector is connected at the factory to
the compressor second−state solenoid connector. No
field connections are required for this component.
NOTE Wiring the module incorrectly will cause false
LED codes. Table 14 describes LED operation when the
module is incorrectly wired and the action required to
correct the problem.
Start−Up and Charging Procedures18
IMPORTANT
If unit is equipped with a crankcase heater, it should
be energized 24 hours before unit start−up to
prevent compressor damage as a result of slugging.
1. Rotate fan to check for binding.
2. Inspect all factory− and field−installed wiring for loose
connections.
3. After evacuation is complete, open both the liquid and
vapor line service valves to release the refrigerant
charge contained in outdoor unit into the system.
4. Replace the stem caps and tighten to the value listed
in Table 1.
5. Check voltage supply at the disconnect switch. The
voltage must be within the range listed on the unit’s
nameplate. If not, do not start the equipment until you
have consulted with the power company and the
voltage condition has been corrected.
6. Set the thermostat for a cooling demand. Turn on
power to the indoor indoor unit and close the outdoor
unit disconnect switch to start the unit.
7. Recheck voltage while the unit is running. Power must
be within range shown on the nameplate.
