4
WIRING DIAGRAMS
Figure 5 – Single Stage or Multi-Stage System (No Heat Pump) with Two Transformers
Single
Stage 1
(SS1)
Multi-
Stage 2
(MS2)
No
Output
Cool
Mode
2nd
Stage
Cool Mode
1st Stage
Blower/
Circulator
Fan Energized
on Call for
Cool (and
Heat if
configured
for Electric
Heat)
No Output
Heat Mode
2nd Stage
Heat
Mode
1st Stage
Optional
24 Volt
(Com-
mon)
Fault
Indicator
(NOT
USED)
24 Volt
(Hot)
Cool
System
Y
G
W/E
C
L
RC
CLASS II
TRANSFORMER
HOT
24VAC
NEUTRAL
120VAC
24 Volt
(Hot)
Heat
RH
120VAC
Remove Jumper Wire
between RH & RC
HOT
24VAC
NEUTRAL
CLASS II
TRANSFORMER
HEATING
COOLING
Y2
W2
Jumper
O/B
O
Energized Constantly
in Cool Mode
B
Energized Constantly
in Heat, Off,
Emergency
Mode
Single Stage
3-wire
Zone Valve
application
Blower/Circulator
Fan Energized
Opens
Valve
(4)
Constant
24 Volt
(Com-
mon)
24 Volt
(Hot)
Cool
System
6
Y
W
C
RC
CLASS II
TRANSFORMER
HOT
24VAC
NEUTRAL
120VAC
24 Volt
(Hot)
Heat
(5)
RH
G
Jumper
Closes
Valve
(6)
Figure 6 – 3-Wire (SPDT) Heat Only Zone Valve Wiring
