50ZHK: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
3
during all moving operations. The unit must be level with in 1/4 in. (6
mm) for proper condensate drainage; the ground-level pad must be level
before setting the unit in place. When a field-fabricated support is used,
be sure that the support is level and that it properly supports the unit.
Step 5 – Select and Install Ductwork
The design and installation of the duct system must be in accordance
with the standards of the NFPA for installation of non-residence type air
conditioning and ventilating systems, NFPA 90A or residence type,
NFPA 90B and/or local codes and ordinances.
Select and size ductwork, supply-air registers, and return air grilles
according to ASHRAE (American Society of Heating, Refrigeration,
and Air Conditioning Engineers) recommendations.
Use the duct flanges provided on the supply- and return-air openings on
the side of the unit. See
for connection sizes and locations.
The 14-in. (356 mm) round or 14 x 20 in. (356 x 508 mm) rectangular
duct collars are shipped inside the unit attached to the base pan in the
indoor blower compartment. They are field-installed and must be
removed from the indoor blower compartment prior to start-up, even if
they are not used for installation. If a corrugated shipping block is used
under the blower housing, remove and discard the block and label.
When designing and installing ductwork, consider the following:
A10021
Fig. 3 – Area Not to be Drilled More Than 3/4-in. (19 mm) Deep
1. All units should have field-supplied filters or accessory filter rack
installed in the return-air side of the unit. Recommended sizes for
2. Avoid abrupt duct size increases and reductions. Abrupt change in
duct size adversely affects air performance.
IMPORTANT:
Use flexible connectors between ductwork and unit to
prevent transmission of vibration. Use suitable gaskets to ensure weather
tight and airtight seal. When electric heat is installed, use fireproof
canvas (or similar heat resistant material) connector between ductwork
and unit discharge connection. If flexible duct is used, insert a sheet
metal sleeve inside duct. Heat resistant duct connector (or sheet metal
sleeve) must extend 24-in. (610 mm) from electric heater element.
3. Size ductwork for cooling air quantity (cfm). The minimum air
quantity for proper electric heater operation is listed in
Heater limit switches may trip at air quantities below those
recommended.
4. Seal, insulate, and weatherproof all external ductwork. Seal,
insulate and cover with a vapor barrier all ductwork passing
through conditioned spaces. Follow latest Sheet Metal and Air
Conditioning Contractors National Association (SMACNA) and
Air Conditioning Contractors Association (ACCA) minimum
installation standards for residential heating and air conditioning
systems.
5. Secure all ducts to building structure. Flash, weatherproof, and
vibration-isolate duct openings in wall or roof according to good
construction practices.
shows a typical duct system with unit installed.
Installing factory-supplied duct flanges;
For 24, 30, and 36 sizes:
• Two round 14-in. (356 mm) duct collars are factory supplied.
• Line up the 6 holes in the duct collar with the pre-drilled holes in the
side panel.
• Fasten duct collar to side panel using field-supplied screws.
For 42, 48 and 60 sizes (See
):
• One round 14-in. (356 mm) duct collar for the supply air connections
and two “L” brackets for the 14-in. x 20-in. (356 x 508 mm) return air
connection are factory-supplied.
• Line up the 6 holes in the supply duct collar with the pre-drilled holes
in the side panel. Fasten duct collar to side panel using field-supplied
screws.
• For the return, remove the 4 screws on the left side of the return and
install one of the “L” flanges on the left side by replacing the 4
screws. Using the 2 dimples below the return, align the bottom of the
“L” flange with the two dimples and attach using filed-supplied
thread-cutting screws.
For the second “L” flange, align flange with the three dimples to the
right of the return and the two dimples above the return and attach
using field-supplied thread-cutting screws.
NOTE:
The factory-installed screws to the right of the return should not
be removed in this process.
A10081
Fig. 4 – Installing Factory-Supplied Duct Flanges
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in damage to unit components.
When connecting ductwork to units, do not drill deeper than 3/4 in. (19
mm) in shaded area shown in
or coil may be damaged.
19.17 in.
(487 mm)
3.92 in.
(100 mm)
3 Factory Installed Screws
(Must not be removed)
Remove 4 screws from left side
of duct opening and reuse to
install the left half of duct
flange.
X = Factory dimples for duct flange attachment.
Install supply duct flange
as shown into existing holes
with field-supplied screws.
