12
The Temperature Rise Tables can also be used to
estimate the air handler airow delivery. When using these
tables for this purpose set the room thermostat to maximum
heat and allow the system to reach steady state conditions.
Insert two thermometers, one in the return air and one in the
supply air. The temperature rise is the supply air temperature
minus the return air temperature. Using the temperature
rise calculated, CFM can be estimated from the TR formula
above. See Specication Sheet and/or Service Manual for
more information.
For heat kit selection, see the Specication Sheet for each
specic Air Handler.
All routing of electrical wiring must be made
through provided electrical knockouts. When removing the
electircal knockouts, take care not to damage the PCB. Do
not cut, puncture or alter the cabinet for electrical wiring.
12.1 Building Electrical Service Inspection
This unit is designed for single-phase electrical supply
only. DO NOT OPERATE AIR HANDLER ON A THREE-
PHASE POWER SUPPLY. Measure the power supply to
the unit. The supply voltage must be measured and be
in agreement with the unit nameplate power requirements
and within the range shown.
12.2 Wire Sizing
Wire size is important to the operation of your equipment.
Use the following check list when selecting the appropri-
ate wire size for your unit.
•
Rating Plate.
• 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.
•
to the unit.
•Wires with dierent insulation temperature rating have
varying ampacities - be sure to check the temperature
rating used.
Refer to the latest edition of the National Electric Code or
in Canada the Canadian Electric Code when determining
the correct wire size.
12.3 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. Protection can be in the form of fusing or
HACR style circuit breakers. The Series and Rating Plate
provides the maximum overcurrent device permissible.
Fuses or circuit breakers are to be sized larger
than the equipment MCA but not to exceed the MOP.
12.4 Electrical Connections – Supply Voltage
Knockouts are provided on the air handler top panel and
sides of the cabinet to allow for the entry of the supply
voltage conductors, as shown in Figure 14. Separate
knock-outs must be used for two circuit Heat-kits. 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. Some codes/
municipalities require the supply wire to be enclosed in
conduit. Consult your local codes.
12.4.1 Air Handler Only (Non-Heat Kit Models)
Installation of Air Handler must follow any
local codes/regulations. The manufacture recommends
that when a heater kit is not installed, a eld supplied
disconnect switch or breaker should be installed in the
electrical circuit that will allow power to be shut-o for
service or maintenance.
The power supply connects to the stripped black and red
wires contained in the air handler electrical compartment.
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. A ground lug is also provided in the electrical
compartment. The ground wire from the power supply
must be connected to this ground lug.
12.4.2 Air Handler - Non-Circuit Breaker Heat Kits
WARNING
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