Allied Air 4AC18LT Series, Installation And Maintenance Instructions Manual

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506469-01 Issue 1008
Roof Mounting
Install unit at a minimum of 6” above surface of the roof to
avoid ice buildup around the unit. Locate the unit above a
load bearing wall or area of the roof that can adequately
support the unit. Consult local codes for rooftop applications.
• Install the unit high enough above the ground or roof to
allow adequate drainage of defrost water and prevent
ice buildup.
• In heavy snow areas, do not locate the unit where drifting
snow will occur. The unit base should be elevated above
the depth of average snows.
NOTE: Elevation of the unit may be accomplished by
construction a frame using suitable materials. If a
support frame is constructed, it must not block drain
holes in unit base.
• When installed in areas where low ambient temperatures
exist, locate unit so winter prevailing winds do not blow
directly into outdoor coil.
• Locate unit away from overhanging roof lines which
would allow water or ice to drop on, or in front of, coil or
into unit.
Slab Mounting
When installing a unit at grade level, install on slab high
enough above grade so that water from higher ground will
not collect around the unit (See Figure 2). Slab should have
a slope tolerance away from the building of 2° or 2” per 5’.
This will prevent ice from building up under the unit during a
defrost cycle. Refer to following roof mounting section for
barrier construction if unit must face prevailing winter winds.
If unit coil cannot be mounted away from prevailing winter
winds, a wind barrier should be constructed (See Figure 3).
Size the barrier at least the same height and width as the
outdoor unit. Mount barrier 24” from the sides of the unit in
the direction of the prevailing winds.
Electrical Wiring
All field wiring must be done in accordance with the National
Electrical Code (NEC) recommendations, Canadian
Electrical Code (CEC) and CSA Standards, or local codes,
where applicable.
Refer to the furnace or blower coil installation instructions
for additional wiring application diagrams and refer to unit
rating plate for minimum circuit ampacity and maximum
overcurrent protection size.
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Unit must be grounded in accordance with national and
local codes. Failure to ground unit properly can result in
personal injury or death.
WARNING
Line voltage is present at all components when unit is
not in operation on units with single pole contactors.
Disconnect all remote electric power supplies before
opening access panel. Unit may have multiple power
supplies. Failure to disconnect all power supplies could
result in personal injury or death.
WARNING
Figure 3
Figure 2
Slab Mounting
Discharge Air
Mounting Slab
Ground Level
Building
Structure