LOW VOLTAGE CONTROL CONNECTIONS
The 24 volt power supply is provided by an internally wired low voltage transformer which is standard on all air handler models. Field supplied low voltage wiring can exit the unit on the top right hand corner or the right hand side panel. Refer to Figure 1. Remove desired knockout and pierce foil faced insulation to allow wiring to pass through. Use as small of a hole as possible to minimize air leakage. Install a 7/8” plastic bushing in the selected hole and keep low voltage wiring as short as possible inside the control box. To further minimize air leakage, seal the wiring entry point at the outside of the unit. The field wiring is to be connected at the screw terminals of the control board.
NOTICE
All wiring must comply with local and national electrical code requirements. Read and heed all unit caution labels.
TYPICAL WIRING WITHOUT ELECTRIC HEAT
GND. LUG |
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POWER
SUPPLY 
1 PHASE ELECTRIC HEAT
WITH CIRCUIT BREAKER
& BREAKER BAR REMOVED
GND. LUG | GND. |
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POWER |
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SUPPLY 1 |
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POWER |
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SUPPLY 2 |
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POWER |
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SUPPLY 3 |
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MAY BE 1, 2, OR 3 |
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CIRCUIT BREAKERS |
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ELECTRIC HEAT
WITHOUT CIRCUIT BREAKER
3 PHASE (10 - 18 KW)
GND. LUG | GND. |
| LUG |
POWER |
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SUPPLY | TERMINAL |
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| BLOCK |
ELECTRIC HEAT |
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WITHOUT CIRCUIT BREAKER | |
SINGLE SOURCE (2.5 - 10 KW) | |
GND. LUG | GND. |
| LUG |
POWER |
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SUPPLY |
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| TERMINAL |
| BLOCK |
CONNECT TRANSFORMER LEADS WITH WIRE NUTS (TYPICAL ALL HEAT KITS)
1 PHASE ELECTRIC HEAT WITH CIRCUIT BREAKER AS SHIPPED FROM FACTORY SINGLE SOURCE
(2.5 - 25 KW) - 25 KW SHOWN
GND. LUG |
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POWER 
SUPPLY
(JUMPER BAR)
MAY BE 1, 2, OR 3
CIRCUIT BREAKERS
POWER WIRING
FIGURE 3: Line Power Connections for PSC Motors
TYPICAL WIRING WITHOUT ELECTRIC HEAT
GND. LUG |
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| GND. | |||||
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POWER
SUPPLY
1 PHASE ELECTRIC HEAT
WITH CIRCUIT BREAKER
& BREAKER BAR REMOVED
GND. LUG |
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| GND. | |||||||
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POWER
SUPPLY 1 
POWER
SUPPLY 2 
POWER
SUPPLY 3 
MAY BE 1, 2, OR 3
CIRCUIT BREAKERS
ELECTRIC HEAT
WITHOUT CIRCUIT BREAKER
3 PHASE (10 - 18 KW)
GND. LUG | GND. |
| LUG |
POWER |
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SUPPLY | TERMINAL |
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| BLOCK |
ELECTRIC HEAT |
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WITHOUT CIRCUIT BREAKER
SINGLE SOURCE (2.5 - 10 KW)
GND. LUG | GND. |
| LUG |
POWER |
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SUPPLY |
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| TERMINAL |
| BLOCK |
1 PHASE ELECTRIC HEAT WITH CIRCUIT BREAKER AS SHIPPED FROM FACTORY SINGLE SOURCE
(2.5 - 25 KW) - 25 KW SHOWN
GND. LUG |
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| GND. | |||
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POWER 
SUPPLY
(JUMPER BAR)
MAY BE 1, 2, OR 3
CIRCUIT BREAKERS
POWER WIRING
FIGURE 4: Line Power Connections for Standard ECM Motors
Johnson Controls Unitary Products | 3 |
