NOTE

Relay contacts shown are thermostatically operated. The accessory relay scheme is required when safety circuits exist in both systems.

Thermostat

Control

Circuit

!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.

THERMOSTAT

O B

Changeover

Energized

In Heat

Y1 G W1

Fan

Relay

E1

E2

W2

C

R

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

SYSTEM

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Emergency

 

 

Heat

 

 

Limit or

 

 

 

 

 

 

 

 

 

Limit or

Relay

 

 

Relay

 

 

Safety

 

 

 

 

 

 

 

 

 

Safety

Switched

 

 

 

 

 

 

 

 

 

 

 

Hot

 

 

 

 

 

 

 

Switches

 

 

 

 

 

 

 

Switches

Output

 

 

Stage 2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

24 VAC

 

 

 

 

 

 

 

120 VAC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Changeover

 

Compressor

 

Heat

Energized

 

Contactor

 

Relay

In Cool

 

Stage 1

 

Stage 1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

HEAT PUMP SYSTEM

TWO COMMONS MUST

BE JUMPERED TOGETHER!

 

Emergency

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

24 VAC

 

 

 

 

 

 

 

 

 

 

 

Neutral

 

 

 

Relay

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Constant

 

 

 

 

Accessory

 

 

 

 

AUXILIARY

 

 

 

 

 

 

 

 

 

 

 

 

 

Output

 

 

 

 

Relay N.O.

 

 

 

 

 

 

HEATING

 

 

 

 

 

 

 

 

 

Contact

 

 

 

 

TRANSFORMER

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AUXILIARY

 

 

 

 

 

HEAT PUMP

 

 

 

 

 

Limit or

 

 

Limit or

 

 

HEATING SYSTEM

 

 

 

TRANSFORMER

 

 

 

 

Safety

 

Safety

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Hot

 

 

 

 

 

 

 

 

Switches

 

 

 

 

 

 

 

 

 

 

 

 

Switches

 

 

 

 

 

 

 

 

24 VAC

 

 

 

 

 

 

 

 

 

120 VAC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Neutral

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 6. Typical wiring diagram for two transformer systems with safety circuits in BOTH systems

15

Page 15
Image 15
White Rodgers 1F92W-51 manual Heat Pump System