Wiring Diagrams
The following is just a sample of the most common types of HVAC sys- tems. Refer to your systems installation manual for wiring information.
HEAT/COOL | HEAT ONLY |
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SINGLE TRANSFORMER | SINGLE TRANSFORMER |
jumper
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| RH |
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Transformer |
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| RC |
| E |
| Hot |
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| R | |
120 VAC |
| 24 VAC |
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| Heating |
| W | M | |
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| Control |
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| O | |
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| Cooling |
| Y | S | |
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| Control |
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| T |
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| A |
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| Fan |
| G | ||
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| T | |||
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| Control |
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Factory- Installed
jumper
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| RH | T | |
Transformer | H | |||
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Hot |
| RC | E | |
120 VAC | 24 VAC |
| R | |
| Heating | W | M | |
| Control | |||
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| Y | S | |
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| Fan |
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| Control | G | T | |
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| HEAT ONLY |
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| COOL ONLY |
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| SINGLE TRANSFORMER |
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| NOTE: Remove factory |
| SINGLE TRANSFORMER | |||||||||||||
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| installed jumper |
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| NOTE: Remove factory | ||||||||||
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| installed jumper |
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| RH | T |
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Transformer |
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| H |
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| Transformer | RH |
| H |
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| Hot |
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| RC |
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| Hot |
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| RC |
| E |
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120 VAC | 24 VAC |
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| R |
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| Heating |
| W | M |
| 120 VAC | 24 VAC |
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| R |
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| Control |
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| W |
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| Y |
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| Cooling |
| Y |
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| Control |
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| A |
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| A |
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| G | T |
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| Fan |
| G |
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| Control |
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HEAT/COOL
5-WIRE
TWO TRANSFORMER
| (HEATING) |
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| Transformer |
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| T |
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| Hot |
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| RH |
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120 VAC | 24 VAC |
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| H |
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| RC | E |
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| R |
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| Heating |
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| W | M |
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| Control |
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| O |
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| Cooling |
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| Y | S |
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| Hot |
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| Control |
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| T |
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120 VAC | 24 VAC |
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| A |
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| Fan |
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| G |
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| T |
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| Control |
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(COOLING) Transformer
NOTE: Cut center of factory installed jumper and bend back
NOTE: Both transformers must be in phase.
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