035-17438-001 Rev. A (901)
12
Unitary Products Group
NOTE:
The furnace’s control system depends on correct
polarity of the power supply and a proper ground connection.
Refer to the furnace control diagnostics section for symptoms
of reversed power supply polarity.
Connect the power supply as shown on the unit wiring label
on the inside of the blower compartment door and refer to
Figure 8. The black furnace lead must be connected to the L1
(hot) wire from the power supply.
The white furnace lead must be connected to neutral. Also,
the green equipment ground wire must be connected to the
power supply ground.
Remove the screw retaining the junction box cover. Route the
power wiring through the unit side panel with a conduit con-
nector or other proper connection. Make wiring connections:
Refer to Figure 8. Replace the wiring box cover and screw.
An alternate wiring method is to use a field provided 2 x 4 box
and cover on the outside of the furnace. Route the furnace
leads into the box using a protective bushing where the wires
pass through the furnace panel.
NOTE:
The power connection leads and wiring box on
upflow units may be relocated to the left side of the furnace.
Remove the screws and cut wire tie holding excess wiring.
Reposition on the left side of the furnace and fasten using
holes provided.
ELECTRICAL CONTROL CONNECTIONS
Install the field supplied thermostat. The thermostat instruc-
tions for wiring are packed with the thermostat. With the ther-
mostat set in the OFF position and the main electrical source
disconnected, complete the low voltage wiring from the ther-
mostat to the terminal board on the CFM programmable
board. Connect Class 2 control wiring: see Figure 9, for sin-
gle stage thermostat wiring: see Figure 10 for two stage ther-
mostat wiring. .
Apply strain relief to thermostat wires passing through the
cabinet.
NOTE:
Some electronic thermostats do not have adjustable
heat anticipators. They may have other type cycle rate adjust-
ments. Follow the thermostat manufacturer's instructions.
The 24volt, 40 VA transformer is sized for the furnace compo-
nents only, and should not be connected to auxiliary devices
such as humidifiers, air cleaners, etc. The transformer may
provide power for an air conditioning unit contactor.
Use copper conductors only.
FIGURE 8 :
Upflow Models - Electrical Wiring
BLK/BLK
WHT/WHT
GRN/GRN
HUM
EAC
WIRING INSIDE
JUNCTION BOX
BURNER
COMPARTMENT
CFM/TIMER
BOARD
BLOWER
COMPARTMENT
IGNITION MODULE
CLASS 2 SYSTEM
CONTROL WIRING
TO THERMOSTAT
DOOR SWITCH
JUNCTION BOX
EAC (HOT)
HUM (HOT)
GND.
N
L1
(HOT)
WHT
GRN
BLK
Set the heat anticipator in the room thermostat as
shown below. Setting it lower will cause short cycles.
Setting it higher will cause the room temperature to
exceed the setpoint.
Two-Stage Thermostat
First Stage
.4 Amps
Second Stage
.1 Amps
Single Stage Thermostat
.4 Amps
FIGURE 9 :
Field Wiring for Single Stage Thermostat
TYPICAL FIELD WIRING - SINGLE STAGE
SINGLE STAGE
THERMOSTAT
HUM
Y2
Y1
Y
R
W1
W2
G
C
O
X/L
Y1
R
W1
G
C
LOW HEAT TIME
ADJUSTMENT
CFM/TIMER BOARD
MINUTE SELECT
10
15
20
TIME OFF
HUM
Y2
Y1
Y
R
W1
W2
O
C
O
X/L
HUM
HEAT PUMP
HUMDISTAT
COOL
HEAT
DELAY
ADJ
P9
P6
W1
W2
10
15
20
MINUTE SELECT
