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4. Remove corner post screws and rigging brackets, then
re- -install screws.
After the unit is placed on the roof curb or mounting pad, remove
the top crating.
OPTIONAL
RETURN
AIR
OPENING
2˝
(50.8mm)
EVAP. COIL
Fig. 7 - - Slab Mounting Detail
Step 6 — Connect Condensate Drain
NOTE: When installing condensate drain connection be sure to
comply with local codes and restrictions.
Model 704D disposes of condensate water through a 3/4 in. (19.05
mm) NPT fitting which exits through the base on the evaporator
coil access side. See Fig. 2 & 3 for location.
Condensate water can be drained directly onto the roof in rooftop
installations (where permitted) or onto a gravel apron in ground
level installations. Install a field- -supplied condensate trap at end of
condensate connection to ensure proper drainage. Make sure that
the outlet of the trap is at least 1 in. (25.4 mm) lower than the drain
pan condensate connection to prevent the pan from overflowing
(See Fig. 8). When using a gravel apron, make sure it slopes away
from the unit.
Connect a drain tube using a minimum of 3/4 - -in. (19.05 mm)
PVC or 3/4 - -in. (19.05 mm) copper pipe (all field- -supplied) at the
outlet end of the 2- -in. (50.8 mm) trap. Do not undersize the tube.
Pitch the drain tube downward at a slope of at least 1- -in. (25.4
mm) for every 10 ft (3.1 m) of horizontal run. Be sure to check
the drain tube for leaks. Prime trap at the beginning of the cooling
season start- -up.
1" (25 mm) MIN .
Fig. 8 - - Condensate Trap
Step 7 — Install Duct Connections
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
Refrigeration, and Air Conditioning Engineers) recommendations.
The unit has duct flanges on the supply- - and return- -air openings
on the side of the unit.
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 1.
2. Avoid abrupt duct size increases and reductions. Abrupt
change in duct size adversely affects air performance.
OPTIONAL
SUPPLY
AIR
OPENING
COND. COIL
A07926
TRAP
OUTLET
2" (51 mm) MIN.
A08001
Society
of
Heating,
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.
(609.59 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
Table 2. 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
(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.
CONFIGURING UNITS FOR DOWNFLOW
(VERTICAL) DISCHARGE
WARNING
!
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.
1. Open all electrical disconnects and install lockout tag before
starting any service work.
2. Remove return duct cover located on duct panel by
breaking four (4) connecting tabs with screwdriver and a
hammer (See Fig. 9 & 10).
3. To remove supply duct cover, break front and right side
connecting tabs with a screwdriver and a hammer. Push
louver down to break rear and left side tabs (See Fig. 9 &
10).
4. If unit ductwork is to be attached to vertical opening flanges
on the unit composite base (jackstand applications only), do
so at this time. Collect ALL screws that were removed. Do
not leave screws on rooftop as permanent damage to the
roof may occur.
5. It is recommended that the unit base insulation around the
perimeter of the vertical return- -air opening be secured to
the unit base with aluminum tape. Applicable local codes
may require aluminum tape to prevent exposed fiberglass.
6. Cover both horizontal duct openings with the duct covers
from the accessory duct cover kit. Ensure opening is
air- -and watertight.
7. After completing unit conversion, perform all safety checks
and power up unit.
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.
7
National
Association
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