6
IO-230F
08/04
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 75
o
C with a 2% voltage drop. Use
the
Table 7
to determine the voltage drop per foot of
various conductors.
10
15
20
25
30
35
40
45
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
Maximum Allowable Length in Feet
to Limit Voltage Drop to 2%*
Minimum Circuit Ampacity (MCA)
Wire Size
(AWG)
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 (Non-Heat Kit Models)
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 Non-Circuit Breaker Heat Kits
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 single-stage or multi-staging. The low voltage
connections are determined by whether the outdoor unit is
a condenser or heat pump. The 24V-control voltage
connects the air handler to the room thermostat and
condenser. Low voltage wiring is to be copper conductors.
A minimum of 18AWG must be used for installations up to
50’ and 16AWG for installations over 50’. Low voltage
wiring can be made through the top of the cabinet or through
either side. See the “Thermostat Wiring” section of this
manual for the ARUF, ARPF and ARPT models for typical
low voltage wiring connections. The Supplemental
Installation Manual included with the AEPT product shows
the wiring diagrams for these models.
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.
