Carrier LIGHT COMMERCIAL CONDENSING UNITS 38HDL018-060 User Manual

Page 3

Step 2 — Rig and Mount Unit

MOUNTING ON GROUND — Mount unit on a solid, level
concrete pad. Position unit so water or ice from roof does
not fall directly into unit. Field-fabricated stacking kits can
be used when units are to be stacked. If conditions or local
codes require unit to be fastened to a pad, 6 field-supplied
tiedown bolts should be used and fastened through slots pro-
vided in unit mounting feet.

MOUNTING ON ROOF — Mount unit on level platform or
frame at least 6 in. (154 mm) above roof surface. Isolate unit
and tubing from structure.

RIGGING

Be sure unit panels are securely in place prior to
rigging.

Keep unit upright. Lift unit using sling. Use cardboard or

padding under sling, and spreader bars to prevent sling dam-
age to unit. See Fig. 3. See Fig. 2 for center of gravity ref-
erence. Install unit so coil does not face into prevailing winds.
If this is not possible and constant winds above 25 mph are
expected, use field-fabricated wind baffle.

NOTE: Field-fabricated wind baffles should be used on all
units with accessory low-ambient control.
Field-fabricated snow stand may be used to raise unit when
operation will be required during the winter. Units may also
be wall mounted using the accessory wall mounting kit.

Step 3 — Complete Refrigerant Piping Connec-
tions —

Outdoor units may be connected to indoor units

using field-supplied tubing of refrigerant grade and condi-
tion. See Tables 1A and 1B for correct line sizes. Do not use
less than 10 ft (3 m) of interconnecting tubing.

DO NOT BURY MORE THAN 36 IN. (922 mm) OF
REFRIGERANT PIPE IN THE GROUND. If any sec-
tion of pipe is buried, there must be a 6 in. (154 m) ver-
tical rise to the valve connections on the outdoor unit.
If more than the recommended length is buried, refrig-
erant may migrate to the cooler, buried section during
extended periods of system shutdown. This causes
refrigerant slugging and could damage compressor at
start-up.

When more than 50 ft (15.2 m) of interconnecting tubing

and more than 30 ft (9.1 m) of vertical lift is used, refer to
Part 3 of the Carrier System Design Manual for design de-
tails, or contact your local distributor.

If either refrigerant tubing or indoor coil is exposed to at-

mospheric conditions for longer than 5 minutes, it must be
evacuated to 1000 microns to eliminate contamination and
moisture in the system.

Run refrigerant tubes as directly as possible, avoiding un-

necessary turns and bends. Suspend refrigerant tubes so they
do not damage insulation on vapor tube and do not transmit
vibration to the structure. Also, when passing refrigerant tubes
through the wall, seal opening so that vibration is not trans-
mitted to structure. Leave some slack in refrigerant tubes be-
tween structure and outdoor unit to absorb vibration. Refer
to separate indoor unit installation instructions for addi-
tional information.

CHECK ACCURATER

௡ CONTROL — The correct

AccuRater (bypass type) refrigerant control is required for
cooling system capacity optimization. An AccuRater device

with field-replaceable piston should be supplied with the in-
door unit. Refer to AccuRater metering device table in sepa-
rate indoor unit installation instructions to determine the correct
AccuRater piston size required for the condenser/evaporator
system being installed.

Note that one of 2 types of the AccuRater devices can be

found on the indoor unit. See Fig. 4. Do not interchange com-
ponents between AccuRater device types. Matching of out-
door unit with indoor unit may require field replacement of
piston. Replace piston, if required, before connecting refrig-
erant lines. Piston replacement instructions are included
in the indoor unit installation instructions. After system in-
stallation is complete, see Refrigerant charging section on
page 8 to check and/or adjust refrigerant charge.

The 38HDL018-060 units may also be installed with units

using a thermostatic expansion valve (TXV). If a TXV is
used, be sure to remove the piston from the indoor coil. See
installation instructions shipped with the TXV for proper po-
sitioning and adjustment.

MAKE PIPING SWEAT CONNECTIONS — Remove plas-
tic caps from liquid and suction service valves. Use refrig-
erant grade tubing. Service valves are closed from the fac-
tory and ready for brazing. After wrapping the service valve

Fig. 3 — Lifting Unit with Sling

NOTE: Arrow on AccuRater body points in free-flow direction, away
from the indoor coil.

Fig. 4 — AccuRater Metering Device Components

TYPE A (BYPASS TYPE)

TYPE B