035-16408-001 Rev. B (101)
Unitary Products Group
7
FIELD CONNECTIONS - CONTROL WIRING
The recommended field connections for specific indoor air
handlers and furnaces are shown in Figures 4 through 7. All
connects to the outdoor unit are made in the low voltage box
in the bottom right corner of the control box. See Figure 3.
Feed all control wiring through the grommet in the bottom of
the box. Care should be taken so that all wire nut connections
are firm with no exposed wires that could short within the box.
If the fault line (X/L) is not connected to the thermostat, it
should be capped securely inside the box.
Variable Speed Air Handlers and Furnaces
- connections
shown in Figure 4. The first stage thermostat signal is con-
nected to Y1 at the air handler/furnace control. It is critical the
Y2 OUT signal is connected to Y at the air handler/furnace
control to properly control the blower speed.
Single Speed Air Handlers and Furnaces
- connections
shown in Figures 5 and 6. It is mandatory to connect the
appropriate blower relay to operate the low speeds. The first
stage thermostat signal is connected directly to Y1 on the
outdoor unit. Do not connect to Y at the indoor control. The
first stage blower operation is controlled by the G signal. It is
critical the Y2 OUT signal is connected to Y at the air handler/
furnace control to properly control the blower speed by
switching the relay to the high speed tap.
Two Stage Furnaces
- connection shown in Figure 7. The
first stage thermostat signal is connected directly to Y1 on the
outdoor unit. Do not connect to Y at the indoor control. The
first stage blower operation is controlled by the G signal. It is
critical the Y2 OUT signal is connected to Y at the furnace
control to properly control the blower speed.
WIRING DIAGRAMS
FIGURE 4 :
WIRING FOR USE WITH VARIABLE SPEED AIR HANDLERS OR FURNACES
OUTDOOR UNIT
CONTACTOR
WIRE NUT
VARIABLE SPEED
FURNACE AND
AIR HANDLER
THERMOSTAT
TYPICAL
TWO STAGE
COOLING
THERMOSTAT
MUST BE USED
X, Y1, Y2, HUM
LOCATED ON CFM
SELECTION BOARD
POWER
CONTROL
FACTORY
(CLASS 1 WIRING)
(CLASS 2 WIRING)
POWER WIRING
208/230-1-60
TS
CONTROL
HUMIDISTAT
GND.
LUG
T2
T1
L2
L1
M1
BLK
RED
BRN
YEL
ORG
PUR
C
R
Y2
Y1
X/L
2
C
R
Y2
Y1
G
W1
W2
X/L
O
X
W2
W1
G
Y
Y1
Y2
C
R
1
HUM
1
CONNECT FOR THERMOSTAT WITH FAULT
LIGHT INDICATOR ONLY, CAPTHIS WIRE
IF NOT USED.
2
HUMIDISTAT: MAKES CIRCUIT ON HUMIDITY FALL
(JUMPER ON CFM SELECTION
BOARD MUST BE REMOVED)
Y2 OUT
