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• Allow sufficient space for airflow clearance, wiring,
refrigerant piping and servicing unit. See Fig. 1.
• Locate unit so that condenser airflow is unrestricted
on all sides and above.
• Unit has legs for mounting on level pad. See Fig. 2
and
Table 1
for weight distribution based
on
recommended support points.
NOTE:
If vibration isolators are required for a par¬
ticular installation, use the data in Table 1 and Fig. 2
to make proper selection.
Step 2 — Rig and Locate the Unit
A CAUTION
Be sure unit panels are securely in place prior to
rigging. Be careful rigging, handling and installing
unit. Improper unit location can cause system mal¬
function and material damage.
RIGGING — Lift units at points 3, 4, 7, 8 (Fig. 2). Use
eyebolts and washers supplied in parts package. Do not
sling unskidded unit. Skidded unit may be slung provided
sling does not contact sides of unit. While unit is on skid,
it can be rolled or dragged.
Step 3 — Mount Compressor
COMPRESSOR MOUNTING
As shipped, the com¬
pressor is held down by special self-locking bolts and
lockwashers. After unit is installed, remove self-locking
bolts one at a time and reassemble with flanged washers
and neoprene snubbers as shown in Fig. 4. The flanged
washers and neoprene snubbers are shipped in a cloth
bag tied to one of the compressor feet. Tighten all 4
bolts, then loosen each until the flanged washer can be
moved sideways with finger pressure.
Step 4 — Complete Refrigerant Piping
Connections
SIZE REFRIGERANT LINES — Consider length of
piping required between outdoor and indoor units,
amount of liquid lift and compressor oil return. Refer to
Part 3 of Carrier System Design Manual for line sizing
information. Refer to indoor unit installation instruc¬
tions for additional information.
Maximum liquid line length is 100 feet. Carefully
determine the minimum expected unit capacity and size
interconnecting lines accordingly. For low load condi¬
tions, determine if there is a need for double suction
risers per Carrier System Design Manual. Consider vapor
line as hot gas line. Consider line sizes for heating as well
as cooling capacities.
IMPORTANT: SPREADER BARS MUST BE USED BETWEEN POINTS
3-4 AND 7-8
n □-7
□
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c
□
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T
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—
COIL
COMPR
SECTION
SECTION
~i
+
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17
3
5
TOP VIEW
LEG LOCATIONS
LIFTING POINTS
Fig. 2 — Weight Distribution
PLACING UNIT — Place unit so that airflow is un¬
restricted above. Provide clearance around the unit as
shown in Fig. 1. Remove 6 hold-down bolts, releasing
skid. The legs are attached to base skid.
A CAUTION
Piping must be properly sized and installed for the
system to operate efficiently.
— FILTER DRIERS — 38AQ units have factory-installed
filter driers. It is not necessary to add filter drier and check
valve arrangements in interconnecting piping. It is recom¬
mended that a field-supplied liquid moisture indicator be
installed in liquid line. Indoor units provide filter driers
with heat pump piping packages, for field installation.
Refer to indoor unit installation instructions for details.
Complete refrigerant piping from indoor coil to out¬
door coil before opening liquid and suction lines at the
heat pump unit. See Table 3 for proper refrigerant charge
and piping selection data.
PROVIDE SAFETY RELIEF — A fusible plug is
located on the liquid line before the liquid valve and on
top of the accumulator (Fig. 3). DO NOT CAP THIS
PLUG. If local code requires additional safety devices,
install as directed.
Block up or suspend unit. With bolts supplied, secure
legs (see Fig. 5) to unit (1, 2, 3, 4, 5 and 6 in Fig. 2 and
Table 1).
Table 1 — Weights
UNIT
38AQ
WEIGHT (lb)
TOTAL
Leg Location
1
2
3
4
5
6
024
2040
204
204
670
670
146
146
028
2160
203
203
592
642
235
285
034
2500
286
286
834
834
130
130
The unit may be mounted on a full pad or on raised
supports at each leg. Weight distribution shown in Fig. 2
will determine type of support required. Bolt unit securely
to pad or supports when positioned and leveled.
HEAD PRESSURE CONTROL —Fan cycling for head
pressure control is a standard offering but functions in
cooling mode only. The no. 2 fan cycles as a function of
liquid pressure sensed by fan cycling pressure switch
(FCPS). Fan no. 3 cycles as a function of outdoor air
temperature through the action of the air temperature
switch (ATS). See Table 2 for settings. These switches are
automatically bypassed in heating mode. Table 4 shows
minimum outdoor ambient temperatures at which units
will operate and provide full cooling capacity.
RECEIVER — No receiver is provided with the unit; it
is recommended that one not be used.
PIPING PROCEDURE — Do not remove caps from
vapor and liquid line stubs in compressor compartment
until piping connections are ready to be made. Pass nitro¬
gen or other inert gas through piping while brazing, to
prevent formation of copper oxide.
Install thermostatic expansion valves in liquid line
ahead of each indoor coil section.
2
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