4
5. Roof the curb prior to setting the unit. Use standard 2 in. x
4 in. wood nailers (provided), insulate and flash (by oth-
ers) as required.
6. Check to ensure that curb is level and securely attached to
structure.
7. Check for sufficient height between the unit base and the
roof to allow for drain trapping.
8. Use polyurethane caulking on top of the curb to seal be-
tween the unit base and the roof curb.
9. Safely lift the unit into place.
The installer is responsible for installing roof curb in accor-
dance with local building and earthquake codes.
Duct/Weather Hood Installation —
Follow
SMACNA and industry guidelines for duct gages, sizing, ma-
terials, insulation and supports. Transition to and from units as
required for proper airflow. When installing ductwork or
weather hoods to unit exterior, use gaskets or caulking around
entire perimeter of flange. Align the duct or hood over the
opening. Check for adequate clearance to doors and other
openings. Install the duct of hood using sheet metal screws
through the unit casing. Carefully remove excess caulking, if
required, from around the flange.
Electrical Connections —
Follow the latest NEC (Na-
tional Electrical Code) and/or other applicable codes for all
electrical wiring and connections, including grounding.
Nameplate data contains line voltage and minimum ampac-
ity for this unit. Separate line voltage power supply should be
run directly from the building distribution panel to the electri-
cal connection on the unit. Consult wiring diagrams provided
with the unit. Follow NEC and applicable codes for conduit
and wire ratings.
Coils
HEATING COILS (HOT WATER, STEAM) — Heating
coils are constructed of copper tube with corrugated fins. Max-
imum operating pressure is 150 psig. Coils are provided with
drain and vent connections. Do not block the air vent; this may
result in poor coil performance. Inlet line strainers are recom-
mended to prevent debris from blocking coil tubes or valves.
Common causes of heating coil damage are:
• improper piping installation
• water hammer
• freezing
• control valve chattering
• internal corrosion from chemicals in fluid
• external corrosion from chemicals in the airstream
COOLING COILS (CHILLED WATER, DIRECT EXPAN-
SION, GLYCOL) — Cooling coils are constructed of copper
tube with corrugated fins. Maximum operating pressure is
150 psig. An IAQ 304SS (indoor air quality 304 stainless steel)
condensate drain pan is located under the coil with drain and
vent connections. Do not block the air vent; this may result in
poor coil performance. Inlet line strainers are recommended to
prevent debris from blocking coil tubes or valves.
Common causes of water cooling coil damage are:
• improper piping installation
• water hammer
• freezing
• control valve chattering
• internal corrosion from chemicals in fluid
• external corrosion from chemicals in the air stream
Direct expansion (DX) cooling coils are thermal counter-
flow construction with same end liquid and suction
connections.
Common causes of DX cooling coil damage are:
• improper piping installation
• freezing (due to excessively low pressure)
• internal corrosion
• external corrosion from chemicals in the air stream
Refrigerant distributors are brass, pressure type with copper
distributor tubes factory installed.
Reassembly of Split Units —
To prevent air and wa-
ter leaks, all units shipped in sections must be carefully assem-
bled and installed on a proper foundation. Split air units are as-
sembled in one piece in the factory to make sure that all pieces
match and the bolt holes line up, and are then split prior to ship-
ping.
• For proper reassembly, housekeeping pad or roof curb
must be level.
• All nuts, bolts, washers, and caulking required for
assembly of the unit are shipped in the supply fan sec-
tion.
• Place all sections on level surface.
• Caulk where indicated on both sides of split panel and
roof flanges, and bolt the base together. See Fig. 6.
• A come-along or hand-operated winch can be used to
tighten the space between unit section.
• Bolt holes may not align as a result of racking during
transit to the job site. In such instances, lift one side with
jack to align holes on wall of the opposite side. After
bolting this wall, remove jack. Then proceed with bolting
the other side, base, floor, and roof. Any racking that is
out of square should realign as the unit settles.
• Check to make sure that all bolts are properly secured.
• Caulk exterior roof seams. See Fig. 7.
CAULKING
a39-4465
Fig. 6 — Caulking Split Panel Flanges
