NOTE
IF SAFETY CIRCUITS ARE IN ONLY ONE OF THE
SYSTEMS, REMOVE THE TRANSFORMER OF THE
SYSTEM WITH NO SAFETY CIRCUITS.
Thermostat
Control
Circuit
THERMOSTAT
CUT AND
TAPE OFF!
Hot
120 VAC | 24 VAC |
O B
Changeover
Energized
In Heat
Y1 G W1
Fan
Relay
E1 | E2 | W2 | C | R |
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| SYSTEM |
Emergency |
| Heat |
| Limit or |
Relay |
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| Relay |
| Safety | |
Switched |
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Output |
| Stage 2 |
| Switches |
Neutral
TRANSFORMER
Changeover |
| Compressor |
| Heat | |||
Energized |
| Contactor |
| Relay | |||
In Cool |
| Stage 1 |
| Stage 1 | |||
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HEAT PUMP SYSTEM
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| TRANSFORMER | Limit or |
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| Emergency |
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| Relay |
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| Hot | Safety |
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| Constant |
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| Switches |
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| Output | 24 VAC |
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| 120 VAC |
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| AUXILIARY HEATING SYSTEM |
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| Neutral |
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DEPENDING ON SYSTEM REQUIRE-
TWO COMMONS MUST
BE JUMPERED TOGETHER!
MENTS, REPLACE WITH A
75VA TRANSFORMER, IF NEEDED
Figure 5. Typical wiring diagram for two transformer systems with NO safety circuits
14