HIGH VOLTAGE!
Disconnect ALL power before servicing. 
Multiple power sources may be present. 
Failure to do so may cause property damage, personal injury or death.
HIGH VOLTAGE!
To avoid property damage, personal injury or death due to electrical shock, this unit MUST have an uninterrupted, unbroken electrical ground. The electrical ground circuit may consist of an appropriately sized electrical wire connecting the ground lug in the unit control box to the building electrical service panel.
Other methods of grounding are permitted if performed in accordance with the National Electric Code (NEC)/American National Standards Institute (ANSI)/National Fire Protection Association (NFPA) 70 and local/state codes. In Canada, electrical grounding is to be in accordance with the Canadian Electric Code (CSA) C22.1.
Building Electrical Service Inspection
This unit is designed for
Nominal Input | Minimum Voltage | Maximum Voltage |
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|
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208/240 | 187 | 253 |
| Table 5 |
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Wire Sizing
Wire size is important to the operation of your equipment. Use the following check list when selecting the appropriate wire size for your unit.
•Wire size must carry the Minimum Circuit Ampac- ity (MCA).
•Refer to the NEC (USA) or CSA (Canada) for wire siz- ing. The unit MCA for the air handler and the optional electric heat kit can be found on the unit Series and Rating Plate.
•Wire size allows for no more than a 2% voltage drop from the building breaker/fuse panel to the unit.
Refer to the latest edition of the National Electric Code or in Canada the Canadian Electric Code when deter- mining the correct wire size. The following table shows the current carrying capabilities for copper conductors rated at 75oC with a 2% voltage drop. Use Table 6 to determine the voltage drop per foot of various conduc- tors.
Maximum Allowable Length in Feet
to Limit Voltage Drop to 2%*
Wire Size |
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| Minimum Circuit Ampacity (MCA) |
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(AWG) |
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10 |
| 15 | 20 | 25 | 30 | 35 | 40 | 45 | |
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14 | 75 |
| 50 | 37 | NR | NR | NR | NR | NR |
12 | 118 |
| 79 | 59 | 47 | NR | NR | NR | NR |
10 | 188 |
| 125 | 95 | 75 | 63 | 54 | NR | NR |
8 | 301 |
| 201 | 150 | 120 | 100 | 86 | 75 | 68 |
6 | 471 |
| 314 | 235 | 188 | 157 | 134 | 118 | 110 |
*Based on NEC 1996 |
| Table 6 |
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Maximum Overcurrent Protection (MOP)
Every installation must include an NEC (USA) or CEC (Canada) approved overcurrent protection device. Also, check with local or state codes for any special regional re- quirements.
Protection can be in the form of fusing or HACR style circuit breakers. The Series and Rating Plate can be used as a guide for selecting the MAXIMUM overcurrent device.
NOTE: Fuses or circuit breakers are to be sized larger than the equipment MCA but not to exceed the MOP.
Electrical Connections – Supply Voltage
USE COPPER CONDUCTORS ONLY.
A knockout is provided on the air handler top panel or side to allow for the entry of the supply voltage conductors. If the knockouts on the cabinet sides are used for electrical con- duit, an adapter ring must be used in order to meet UL1995 safety requirements. An NEC or CEC approved strain relief is to be used at this entry point. The wire is to be sized in accordance with the “Electrical Wire and MOP” section of this manual. Some areas require the supply wire to be en- closed in conduit. Consult your local codes.
Air Handler Only (Non-Heat Kit Models)
The building supply connects to the stripped black and red wires contained in the air handler electrical compartment cav- ity. A ground screw is also contained in this area. Attach the supply wires to the air handler conductors as shown in the unit wiring diagram using appropriately sized solderless con- nectors or other NEC or CEC approved means.
Air Handler With Non-Circuit Breaker Heat Kits
A terminal block is provided with the HKR kit to attach the power supply and air handler connections. Follow the HKR Installation Manual and wiring diagram for complete wiring details.
Air Handler With Heat Kits Containing a Circuit Breaker
HKR models with a “C” suffix contain a circuit breaker(s). The air handler has a plastic cover on the access panel that will require either one or both sections to be removed to al- low the heat kit circuit breaker(s) to be installed. See the HKR Installation Instructions for further details. The air han- dler wires and supply wires are installed directly onto the HKR circuit breaker(s) as shown in the HKR Installation Manual and wiring diagram.
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