White Rodgers 1F92W-51 Installation & Operation Manual page 15

Relay contacts shown are thermostatically operated. The
accessory relay scheme is required when safety circuits
exist in both systems.
O B
Changeover
Energized
In Heat
Changeover Compressor
Energized
In Cool
HEAT PUMP SYSTEM
TWO COMMONS MUST
BE JUMPERED TOGETHER!
Figure 6. Typical wiring diagram for two transformer systems with safety circuits in BOTH systems
NOTE
Y1 G E1
W1
Emergency
Fan
Relay
Switched
Relay
Output
Emergency
Heat
Contactor Relay
Stage 1 Stage 1
HEATING SYSTEM
Thermostat
Control
Circuit
THERMOSTAT
E2 W2 C R
Limit or
Heat
Relay
Switches
Stage 2
Relay
Constant
Output
AUXILIARY
Limit or
Safety
Switches
CAUTION
!
Polarity must be observed. If the HOT
side of the second transformer is
jumpered to the COMMON side of the
first transformer a short will be made.
Damage to equipment will occur when
power is restored.
SYSTEM
Safety
Hot
24 VAC 120 VAC
Neutral
24 VAC
Accessory
AUXILIARY
Relay N.O.
HEATING
Contact
TRANSFORMER
HEAT PUMP
TRANSFORMER
Hot
24 VAC
120 VAC
Neutral
Limit or
Safety
Switches
Limit or
Safety
Switches
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