7
APPLICATION DATA
Operating limits
Varifan III (option)
The Carrier Varifan III allows adjustment of the fan speed or of
the three-phase motors (400 V-3 ph-50 Hz) at low outdoor
temperatures.
Varifan III is an adjustment device that is directly controlled by
a pressure transducer that permits very precise maintenance of
the condensing pressure.
38AJ/AZ
008-024
030-036
046-074
Min. outdoor air temperature
°
C
Unit with Varifan option
-18
-18
-18
Standard unit
12
2
0
INSTALLATION
SAFETY CONSIDERATIONS
Installation, start-up and servicing this equipment can be
hazardous due to system pressures, electrical components and
equipment location (roofs, elevated structures, etc.).
NOTE: Only trained, qualified installers and service
mechanics should install, start-up and service this equipment.
When working on the equipment, observe precautions in the
literature, and on tags, stickers, and labels attached to the
equipment.
•
Follow all safety codes.
•
Wear safety glasses and work gloves.
•
Use care in handling, rigging and setting down bulky
equipment.
WARNING: Before doing any work ensure that the power
supply (400 V and 230 V) is disconnected, and switches and
isolators are opened and tagged.
During operation some parts of the unit reach or exceed
temperatures of 70
°
C (e.g. compressor discharge side,
discharge line). Only trained and qualified engineers, aware of
these hot surfaces, are allowed to perform maintenance
operations.
Preliminary checks
Check equipment received
•
Inspect the unit for damage or missing parts. If damage is
detected, or if shipment is incomplete, immediately file a
claim with the shipping company.
•
Confirm that the unit received is the one ordered.
Compare the nameplate data with the order.
•
Confirm that all accessories ordered for on-site installation
have been delivered, and are complete and undamaged.
Moving and siting the unit
Moving
Do not remove skids, pallets or protective packaging until the
unit is in its final position. Move the chiller using tubes or
rollers, or lift it, using slings of the correct capacity.
Siting
Before siting the unit check that :
•
the permitted loading at the site is adequate or that
appropriate strenghtening measures have been taken.
•
the surface is horizontal, flat and intact.
•
there is adequate space around the unit to make power and
water connections for service and air flow.
•
there are adequate support points and that they are in the
right places.
•
the location is not subject to flooding.
•
where heavy snowfall is likely and long periods of sub-
zero temperatures are normal, provision has been made to
prevent snow accumulating by raising the unit above the
height of drifts normally experienced.
Baffles may be necessary to deflect strong winds and to
prevent snow from blowing directly into the unit. They
must not restrict air flow into the unit.
CAUTION: Before lifting the unit, check that all casing panels
are securely fixed in place. Lift and set down the unit with
great care. Tilting and jarring can damage the unit and impair
unit operation. Only use slings at the designated lifting points
which are marked on the unit.
The 38AJ/AZ units can be hoisted with rigging or lifted by
forklift. Coils should always be protected against crushing
while a unit is being moved. Use struts or spreader bars to
spread the slings above the unit. Do not tilt a unit more than 15
°
.
WARNING: Never push or lever on any of the enclosure panels
of the unit. Only the base of the unit frame is designed to
withstand such stresses.
REFRIGERANT CONNECTIONS
Size the refrigerant lines. Consider the length of piping
required between condensing unit and evaporator, the amount
of liquid lift, and the compressor oil return.
Refer to the dimensional drawings for the size, type and
location of the suction and liquid line pipe connections. Refer
to the Carrier System Design Manual (Refrigerant lines).
Include a liquid receiver in the installation.
