Page 4
# 504,465M
Electrical Wiring
All field wiring must be done in accordance with the
National Electrical Code (NEC) recommendations,
Canadian Electrical Code (CEC) and CSA Standards, or
local codes, where applicable.
Refer to the furnace or blower coil Installation Instructions
for additional wiring application diagrams and refer to unit
rating plate for minimum circuit ampacity and maximum
overcurrent protection size.
Unit must be grounded in accordance with national
and local codes.
1. Install line voltage power supply to unit from a properly
sized disconnect switch.
2. Install room thermostat on an inside wall that is not
subject to drafts, direct sunshine, or other heat
sources.
3. Install low voltage wiring from outdoor to indoor unit
and from thermostat to indoor unit (see Figure 2 on
this page and Figure 7 on page 14).
4. Ground unit at unit disconnect switch or to an earth
ground.
SCU14M and Furnace (Gas or Electric)
Thermostat Connections
(Some connections may not apply.
Refer to specific thermostat and furnace.)
Figure 2
COMPRESSOR
COMMON
POWER
1ST STAGE AUX. HEAT
INDOOR BLOWER
Y
C
W2
R
W1
G
2ND STAGE AUX. HEAT
COMMON
COMMON
LOW PRESSURE
SWITCH
Y
C
W2
R
W1
G
Typical
Furnace
Thermostat
Condensing
Unit
YELLOW
BLACK
Figure 3
Unit Components
CONDENSER FAN
(NOT SHOWN)
TOP OF CABINET
CONTACTOR
RUN CAPACITOR
TERMINAL BOX
LIQUID LINE
SERVICE VALVE
AND GAUGE
PORT
SUCTION VALVE
AND GAUGE PORT
COMPRESSOR
LOW PRESSURE
SWITCH
HIGH PRESSURE
SWITCH
GROUND LUG
LINE STUBS
