6
.
Step 3 — Install Ductwork
UPFLOW INSTALLATION If return air is to be ducted,
install duct flush to the floor. Only use the return-air opening
provided. All return air must pass through the coil.
HORIZONTAL INSTALLATIONS Be sure installation
complies with all applicable building codes, which may require
installation of a secondary condensate pan.
NOTE
:
To ensure proper drainage for horizontal installations,
unit must be installed so it is within
1
/
8
-in. pitch of the length
and width of the unit.
1. Arrange support for unit by setting it in or above
secondary condensate pan.
2. When suspending unit from ceiling, dimples in casing
indicate proper location of screws for mounting metal
support straps.
DUCT CONNECTIONS Connect supply-air duct over
outside of
3
/
4
-in. flange provided on supply-air opening. Secure
duct to flange with proper fasteners for type of duct used, and
seal duct-to-unit joint.
Duct connection flanges are provided at the discharge air unit
connection.
Use flexible connectors between ductwork and unit to prevent
transmission of vibration. Ductwork passing through
unconditioned space must be insulated and covered with vapor
barrier.
DUCTWORK
ACOUSTICAL
TREATMENT
Metal
duct systems that do not have a 90
elbow and 10 feet of main
duct to first branch takeoff may require internal acoustical
insulation lining.
As an alternative, fibrous ductwork may be used if constructed
and installed in accordance with the latest edition of SMACNA
(Sheet Metal and Air-Conditioning Contractors’ National
Association) construction standard on fibrous glass ducts. Both
acoustical lining and fibrous ductwork shall comply with
National Fire Protection Association Standards 90A or B as
tested by UL (Underwriters Laboratories) Standard 181 for
Class 1 air ducts.
Step 4 — Connect Piping
CONDENSATE PIPING
The unit is supplied with a
3
/
4
-in.
female pipe thread drain connection to connect drain piping.
When installing the unit, follow these recommendations:
• Condensate piping should slope downward in the
direction of condensate flow, with a minimum gradient
of 1 inch per 100 inches.
• Condensate piping should be installed in such a way that
it does not block the front service panel.
• A drain trap may be required by local codes and is
recommended for odor control.
• The differential height between inlet and outlet should be
at least three inches. The differential height between the
bottom of the trap and outlet should also be three inches.
See Fig. 4.
Fig. 4 —Condensate Drain Trap
• Auxiliary drain should be connected and run to a location
where it is easily visible when it becomes active
suggesting a problem with the main drain system.
• When multiple units are connected to a common
condensate drain, ensure that the drain is large enough to
cope with the volume of condensate from all units. It is
also recommended to have an air vent in the condensate
piping to prevent air locks.
• Insulate the drain line to prevent sweating and provide
proper support to prevent undue stress.
• Condensate piping must not be installed where it may be
exposed to freezing temperatures.
REFRIGERANT PIPING
When connecting from an indoor unit to an outdoor unit,
follow these procedures:
• Check for maximum height drop and length of
refrigerant piping between the indoor and outdoor unit. If
the difference is more than 33 feet, consider mounting
the outdoor unit above indoor unit.
• Refrigerant piping connection between indoor and
outdoor units should be performed once the units are
secured at their respective installation locations.
• The refrigeration piping starts at the indoor unit and ends
at the outdoor unit.
• There must be less than 15 bends in the refrigeration
piping.
• The refrigerant piping should be dry and free of dust and
other contaminants.
• The bending angle of the refrigerant pipe should not
exceed 90°F and the bending radius should be as large as
possible to prevent any breakage in piping.
• Use a torque wrench for flare nuts. Refer to Table 3 for
flare nut torque recommendations.
• Use proper cutting and flaring tools to avoid leakage.
Table 3 —Flare Nut Torque Recommendations
• Before insulating the suction and liquid refrigeration
pipes, perform pressure and leak tests. For details, see
the outdoor unit installation manual. Insulating both
suction and liquid refrigerant pipes is required.
• Vacuuming and charging of the system should be carried
out as described in the outdoor unit installation manual.
IMPORTANT:
If the unit is installed in the ceiling, be sure
that the ceiling grid is supported separately from the unit.
The ceiling grid must not be supported by any part of the
unit, grille, or any associated wiring or piping work.
CAUTION
When connecting from an indoor unit to an outdoor unit,
the isolation valve at the outdoor unit should be in the
closed position throughout the refrigerant piping process.
Failure to follow this procedure may result in equipment
damage.
Outside Diameter (in.)
Recommended Torque (ft-lb)
1/4
15
3/8
26
1/2
41
5/8
48
