Technical Guide

635425-YTG-D-0413
10 Johnson Controls Unitary Products
CONVENTIONAL CONTROL WIRING (24 VAC)
* Optional dehumidification humidistat switch contacts open on rise.
Notes:
1. “Y/Y2” Terminal on air handler control board must be connected for full CFM and applications requiring 60 second blower off delay for SEER enhancement.
2. Remove humidistat jumper on air handler control board.
3. For heat pump applications - set MODE jumper on air handler control board to the HP position.
4. To change quantity of heat during HP defrost cycle - reverse connections at W1 and W2 on air handler control board.
FIGURE 2: COOLING MODELS WITH ELECTIC HEAT WIRING
Air Handler Control Wiring
Typical A/C - Cooling only Applications
THERMOSTAT
AIR HANDLER
BOARD
1 - STAGE
AIR CONDITIONING
RR
G
Y
W1
W2
C
G
W1
W2
Y
C
Y/Y2
Y1
O
HUM
X / L
COM
HUMIDISTAT
THERMOSTAT
AIR HANDLER
BOARD
1 - STAGE
AIR CONDITIONING
RR
G
Y
W1
W2
C
G
W1
W2
Y
C
Y/Y2
Y1
O
HUM
X / L
COM
HUMIDISTAT
Air Handler Control Wiring
Typical A/C with Electric Heat Applications
FIGURE 3: SINGLE-STAGE HEAT PUMP WIRING
CONTROL WIRING - Air Handler
And UPG Single Stage HP Systems
Single Stage HP with Standard Demand Defrost Control Board
THERMOSTAT
AIR HANDLER
BOARD
1 - STAGE
HEAT PUMP
RR R
GG
Y
W / W1
W
O
O
O
X / L X / L
X / L
C C
Y/Y2
Y1
Y
W1 66
W2
W1
HUM
COM
HUMIDISTAT
*
W2
E
FIGURE 4: TWO-STAGE HEAT PUMP WIRING
CONTROL WIRING - Air Handler & UPG HP Systems
Two Stage H/P with York Guard VI Board & Copeland “Ultra Tech”
Conventional Application - Not Hot Heat Pump
THERMOSTAT
AIR HANDLER
BOARD
2 - STAGE SCROLL
HEAT PUMP
RR R
GG
Y2
E
W
W
O O
O
X / L X / L X / L
C
C
Y/Y2
Y1
Y1
Y2 OUT
Y2
W2 OUT
W1 OUT
BS
W2
W1
HUM
COM
HUMIDISTAT
*
Y1