Carrier 48EL - Manual

Number One
AirConditbninq
Maker
Division of
Carrier Corporation
Carrier Parkway • Syracus N Y 13221
Combination Heating/Cooling Units
INTRODUCTION
The 48EL and EM combination heating/cooling
units are complete systems designed for outdoor
installation on slab or rooftop.
Installation consists of: rigging and mounting
the unit, attaching ductwork, making single gas,
electrical
and condensate connections, and
attaching thermostat leads. A field-furnished filter
rack is required in the return airstream.
RECEIVING THE UNIT
Examine the unit carefully for any damage
incurred in shipment. If damaged, file claim with
transportation company immediately.
Check unit nameplate to ensure that unit
electrical requirements match available power
supply, and that unit is designed for use with the
proper gas type (natural or liquefied petroleum).
INSTALLATION
Check national and local gas and electrical
codes and local building codes for any special
installation requirements.
Unit Location — Install unit outdoors. Maintain
clearance of at least 2 ft from building. Unit may
face in any direction since neither the condenser
air inlet nor the flue outlet (Fig. 1) are affected by
wind. Do not locate unit near sources of con­
taminated air.
Although the unit is weatherproof, position
unit so that water and ice from roofs or eaves
cannot fall directly on the unit. •
SPACE LIMITATIONS — Provide sufficient space
for unimpeded airflow and for wiring and servicing
unit (Fig. 1).
OUTSIDE AIR LIMITATIONS - Although there
are no restrictions on either the percentage or the
temperature of the outside air circulated thru the
unit, the rate of moisture condensation from the
combustion process increases significantly when
return air temperature drops below 50 F. Protect
the drain holes in the bottom pan against ice
buildup if outside air of below freezing tempera­
ture is used.
VIBRATION ISOLATION - The unit compressor,
evaporator fan and condenser fan are mounted on
isolators to minimize vibration. Additional
isolation is not required for slab mounting. With
some types of roof construction, however, the use
of field-furnished rubber pad type isolators may be
advisable.
Unit Rigging
1. Sling the unit perpendicularly to shipping skid
runners. Use spreader bars to prevent damage
from sling or cable.
2. Raise unit to desired location and remove
shipping skid.
3. Mount and level the unit as indicated in Unit
Support and Mounting section.
Unit Support and Mounting
LEVELING THE UNIT - Level the unit from end
to end but pitch the unit slightly (3/8 to 1/2 in.)
towards the condensate drain on the service access
face of the unit (Fig. 1). Use the unit frame as a
leveling reference.
SLAB MOUNTING ^ Mount the unit on a
concrete pad, cement blocks, bricks or creosoted
wood of sufficient area and strength to support the
unit weight (Table 1) without distortion or damage
and maintain the drainage pitch recommended
above.
A gravel apron prevents grass and foliage from
obstructing the condenser air inlet (Fig. 1).
FLAT OR RECESSED ROOF MOUNTING should
be as close as possible to the roof duct opening.
Place the unit on at least 2 wooden 2 x 4 in. or 2 x
6 in. sleepers.
Sleepers may be perpendicular to or parallel to
the unit mounting rails, but must span at least 2
roof joists or purlins to distribute unit weight. Set
the sleepers in roof cement or mastic. Do not plug
drain
holes in the compressor or furnace
compartment.
Do not support the unit by the ends of the base
rails, nor use vibration isolators at these points.
Unit will not be properly supported and could sag
in the middle.
PITCHED ROOF MOUNTING - Construct a
sturdy welded or bolted frame of 1-1/2 x 1-1/2 x
1/4 in. or larger angle iron, with frame members at
right angles to unit rails. Make provisions for
securing unit to frame. Use roof cement or mastic
where frame is in contact with roof.
© Carrier Corporation 1978 Form 48EL-1SI