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 Ampacity (MCA).
Refer to the NEC (USA) or CSA (Canada) for wire sizing. 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 determining the correct wire size. The following table shows the current carrying capabilities for copper conductors rated at 75oC with a 2% voltage drop. Use the Table 7 to determine the voltage drop per foot of various conductors.
Maximum Allowable Length in Feet
to Limit Voltage Drop to 2%*
Wire Size |
| 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 |
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*Based on NEC 1996
Table 7
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 requirements.
This 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 conduit, 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 enclosed in conduit. Consult your local codes.
Air Handler Only
The building supply connects to the stripped black and white wires contained in the air handler electrical compartment cavity. 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 connectors or other NEC or CEC approved means.
Air Handler With
A terminal block is provided with the HKR kit to attach the 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 allow the heat kit circuit breaker(s) to be installed. See the HKR Installation Instructions for further details. The air handler wires and supply wires are installed directly onto the HKR circuit breaker(s) as shown in the HKR Installation Manual and wiring diagram.
Low Voltage Connections
Several combinations of low voltage schemes are available, depending on the presence of a heat kit and whether the heat kit is
REFRIGERANT LINES
WARNING
TO PROTECT THE UNIT WHEN WELDING CLOSE TO THE PAINTED SURFACES, THE USE OF A QUENCHING CLOTH IS STRONGLY ADVISED TO PREVENT SCORCHING OR MARRING OF THE EQUIPMENT FINISH. SOLDER WITH A MINIMUM OF 5% SILVER IS RECOMMENDED.
Tubing Preparation
All cut ends are to be round, burr free, and cleaned. Failure to follow this practice increases the chances for refrigerant leaks. The suction line is spun closed and requires pipe cutters to cut off the closed end.
Post Brazing
Quench all welded joints with water or a wet rag.
6 | 08/04 | |
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