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PH4G--B: Installation Instruction
Rigging/Lifting of Unit (See
Lifting holes are provided in base rails as shown.
1. Attach shackles, clevis pins, and straps to the base rails of the unit.
Be sure materials are rated to hold the weight of the unit (See
Fig.
5).
2. Attach a clevis of sufficient strength in the middle of the straps.
Adjust the clevis location to ensure unit is lifted level with the
ground.
After the unit is placed on the roof curb or mounting pad, remove the top
skid.
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.
The unit has duct flanges on the supply- and return-air openings on the
side of the unit.
WARNING
!
PERSONAL INJURY HAZARD
Failure to follow this warning could result in personal injury or death.
For vertical supply and return units, tools or parts could drop into
ductwork. Install a 90 degree turn in the return ductwork between the
unit and the conditioned space. If a 90 degree elbow cannot be installed,
then a grille of sufficient strength and density should be installed to
prevent objects from falling into the conditioned space. Units with
electric heaters require 90 degree elbow in supply duct.
When designing and installing ductwork, consider the following:
1. All units should have field-supplied filters or accessory filter rack
installed in the return-air side of the unit. Recommended sizes for
filters are shown in
Table
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.
to duct flanges. Use suitable gaskets to ensure weather-tight and
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
Fig.
5)
1.
Configuring Units for Downflow (Vertical) Discharge
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury or death.
Before performing service or maintenance operations on the system,
turn off main power to unit and install lockout tag. There may be more
than one disconnect switch.
1. Open all electrical disconnects and install lockout tag before
starting any service work.
2. Remove horizontal (metal) ductcovers to access vertical
(downflow) discharge duct knockouts in unit basepan. (See
3. To remove downflow return and supply knockout covers, break
front and right side connecting tabs with a screwdriver and hammer.
Push cover down to break rear and left side tabs.
Horizontal Duct Covers
Basepan
Downflow
(Vertical)
Supply
Knockout
Fig. 6 – Supply and Return Duct Opening
NOTE: These panels are held in place with tabs similar to an electrical
Table
2.
knockout. Reinstall horizontal duct covers
factory. Insure openings are air and watertight.
NOTE: The design and installation of the duct system must be in
accordance with the standards of the NFPA for installation of
nonresidence-type air conditioning and ventilating systems, NFPA 90A
or residence-type, NFPA 90B; and/or local codes and ordinances.
Adhere to the following criteria when selecting, sizing, and installing the
duct system:
1. Units are shipped for side shot installation.
2. Select and size ductwork, supply-air registers, and return-air grilles
according to American Society of Heating, Refrigeration and Air
Conditioning Engineers (ASHRAE) recommendations.
3. Use flexible transition between rigid ductwork and unit to prevent
transmission of vibration. The transition may be screwed or bolted
airtight seal.
7
WARNING
!
(Fig.
6) shipped on unit from
Fig.
6.)
A09510
Basepan
Downflow
(Vertical)
Return
Knockout
A09518
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