DUCTWORK
Ductwork should be designed and sized according to the
methods in Manual Q of the Air Conditioning Contractors of
America (ACCA).
A closed return duct system shall be used. This shall not
preclude use of economizers or outdoor fresh air intake. The
supply and return air duct connections at the unit should be
made with flexible joints to minimize noise.
The supply and return air duct systems should be designed for
the CFM and static requirements of the job. They should NOT
be sized to match the dimensions of the duct connections on
the unit.
CAUTION: When fastening ductwork to side duct flanges on
unit, insert screws through duct flanges only. DO
NOT insert screws through casing.
Outdoor ductwork must be insulated and water-
proofed.
Refer to Figure 4 for information concerning side and bottom
supply and return air duct openings.
FILTERS
2" filters are supplied with each unit. 1" replacement filters may
be used with no modification to the filter racks. Filters must
always be installed ahead of the indoor coil and must be kept
clean or replaced with same size and type. Dirty filters will
reduce the capacity of the unit and will result in frosted coils or
safety shutdown. Minimum filter area and required sizes are
shown in Table 3.
CONDENSATE DRAIN
Plumbing must conform to local codes. Use a sealing
compound on male pipe threads. Install a condensate drain line
from the 3/4" female connection on the unit to spill into an open
drain.
NOTE: The condensate drain line MUST be trapped to provide
proper drainage. See Figure 2.
SERVICE ACCESS
Access to all serviceable components is provided by five
removable panels:
•
Compressor compartment
•
Heater compartment
•
Blower compartment
•
Main control box
•
Filter compartment
Refer to Figure 4 for location of these access panels.
THERMOSTAT
The room thermostat should be located on an inside wall
approximately 56" above the floor where it will not be subject
to drafts, sun exposure or heat from electrical fixtures or
appliances. Follow manufacturer’s instructions enclosed with
thermostat for general installation procedure. Color coded
insulated wires (#18 AWG) should be used to connect
thermostat to unit. Eight conductors are required.
The subbase on the low voltage thermostat includes an
“Emergency Heat” position on the system switch and a pilot
light. In the “Emergency Heat” position, the thermostat will
provide electric resistance heat only. The compressors will not
run. The pilot light will indicate that the switch is on “EM HT”.
Nine conductors are required for this application.
POWER AND CONTROL WIRING
Field wiring to the unit must conform to provisions of the
National Electrical Code, ANSI / NFPA (latest edition) and/or
local ordinances. The unit must be electrically grounded in
accordance with N.E.C. ANSI / NFPA (latest edition) or local
codes. Voltage tolerances which must be maintained at the
compressor terminals during starting and running conditions
are indicated on the unit Rating Plate and Table 1.
The internal wiring harness furnished with this unit is an integral
part of a UL and C.G.A. design certified unit. Field alteration to
comply with electrical codes should not be required.
A disconnect switch should be field provided for the unit. The
switch must be separate from all other circuits. Refer to Figure
4 for installation locations. If any of the wire supplied with the
unit must be replaced, replacement wire must be of the type
shown on the wiring diagram.
Electrical line must be sized properly to carry the load. USE
COPPER CONDUCTORS ONLY. Each unit must be wired with
a separate branch circuit fed directly from the meter panel and
properly fused.
CAUTION: When connecting electrical power and control wir-
ing to the unit, waterproof type connectors MUST
BE USED so that water or moisture cannot be
drawn into the unit during normal operation. The
above waterproofing conditions will also apply
when installing a field-supplied disconnect switch.
Refer to Figure 3 for typical field wiring and to the appropriate
unit wiring diagram for control circuit and power wiring
information. Refer to Table 2 for electrical data.
ELECTRIC HEATERS
Supplemental electric heaters are available as field-installed
accessories. Refer to Form 530.18-N9.1V for accessory
instruction. These UL and C.G.A. approved heaters are located
within the central compartment of the unit (see Figure 4 for
access panel) with the heating elements extending into the
supply air chamber. All accessory heater kits contain a single
point power kit.
Fuses are supplied, where required, with the accessory kits.
Some KW sizes require fuses and others do not. Refer to the
accessory instruction for electrical data.
COMPRESSORS
The compressors are mounted on springs which have been
tightened down for shipment only. After the unit is installed,
back out the compressor bolts until the sleeve clears the top
grommet.
FIG. 2 - RECOMMENDED DRAIN PIPING
511.06-N2W
4
Unitary Products Group
