Typical wiring when using the evaporator defrost control (EDC):
Cooling Split System and AY28X079 Evaporator Defrost Control
R
Y
G
W
B
Red (R)
Y
Y Low
Orange
Green (G)
White (W1)
White (W2)
White (W3)
Blue (B)
R
Y
O
G
W
X2
B
Red
Yellow
Orange
Brown / X2
Blue
EDR-1
EDC
EDR
Y
B
Red (R)
Y
Y Low
Green (G)
White (W1)
White (W2)
White (W3)
Blue (B)
EDC
Heat Pump Split System and AY28X084 Evaporator Defrost Control
Thermostat
Air handling unit
Thermostat
Pg. 5
Heat pump
unit
Air handling unit
Cooling
unit