Carrier 38AUZ - Complete Refrigerant Piping Connections; Determine Refrigerant Line Sizes

11
horizontal is not less than 45 degrees. Raise and set the
unit down carefully.
If it is necessary t o roll the unit i nto position, mount the
unit on longitudinal rails, using a minimum of 3 rollers.
Apply force to the rails, not the unit. If the unit is to be
skidded into position, place it on a large pad and drag it
by the pad. Do not apply any force to the unit.
Raise from above to lift the unit from the rails or pad
when unit is in its final position.
After the unit is in position, remove all shipping material s
and top crating.
Step 5 — Complete Refrigerant Piping
Connections
IMPORTANT: Do not bury re frigerant piping
underground.
IMPORTANT: A refrigerant receiver is not provided
with the unit. Do not install a receiver.
Provide Safety Relief —
If local codes dictate an additional safety relief device,
purchase locally and install locally. Installation will
require the recovery of the factory shipping charge before
the factory tubing can be cut and the supplemental relief
device is installed.
Model 38AUD has two separate refrigeration systems. If
required, each circuit will require a field-supplied/installed
supplemental relief device.
Check 38AU Model with Evaporator Coil Connections —
Confirm before installation of unit that the evaporator coil
connec tions are consistent with this 38AU model. See
Table 3 on page 9.
Determine Refrigerant Line Sizes —
Select the recommended line sizes for 38AUZ and
38AUD unit from the appropriate tables.
Determine the linear length of interconnecting piping
require d between the outdoor unit and indoor unit
(evapora tor). Consider and identify also the a rrangement
of the tubing path (quantity and type of elbows in both
lines), liquid line solenoid size, filter drier and any other
refrigeration specialties located in the liquid line. Refer to
the indoor unit installation instructions for additional
details on refrigeration specialties devices.
Determ ine equivalent line length adjustment s for path and
compone nts and add to linear line lengths. See Table 4,
Equivalent Lengths for Common Fittings, for usual fitting
types. Also identify adjustments for refrigeration
specialties. Refer to Part 3 of the Carrier System Design
Manual for additional data and information on equivalent
lengths.
Table 4 – Equivalent Lengths for Common Fittings
(EN units)
mm
Ref
Nominal
Tube OD
(in)
Elbows
90
Std
90
Lrad
90
Street
45
Std
45
Street
9.5
3
/
8
0.40 0.24 0.67 0.18 0.30
12.7
1
/
2
0.43 0.27 0.70 0.21 0.34
15.9
5
/
8
0.49 0.30 0.76 0.24 0.40
19.1
3
/
4
0.55 0.37 0.88 0.27 0.46
22.2
7/
8
0.61 0.43 0.98 0.27 0.49
28.6 1
1
/
8
0.79 0.52 1.25 0.40 0.64
34.9 1
3
/
8
1.01 0.70 1.71 0.52 0.91
41.3 1
5
/
8
1.22 0.79 1.92 0.64 1.04
54.0 2
1
/
8
1.52 1.01 2.50 0.79 1.37
mm
Ref
Nominal
Tube OD
(in)
Tees
Branch
Flow
Straight-Thru
No
Reduct
Reduce
25%
Reduce
50%
9.5
3
/
8
0.79 0.24 0.34 0.40
12.7
1
/
2
0.82 0.27 0.37 0.43
15.9
5
/
8
0.91 0.30 0.43 0.49
19.1
3
/
4
1.07 0.37 0.52 0.55
22.2
7/
8
1.22 0.43 0.58 0.61
28.6 1
1
/
8
1.52 0.52 0.70 0.79
34.9 1
3
/
8
2.13 0.70 0.94 1.01
41.3 1
5
/
8
2.44 0.79 1.13 1.22
54.0 2
1
/
8
3.05 1.01 1.43 1.52
NOTE: Equivalent line lengt hs will vary based on tube
diameter. Calculate equivalent line length for each pipe by
adding e quivalent length adj ustments to linear lengths for
each pipe.
Enter the appropriate table to select the recommended line
sizes.
Model: Line Sizes Table Quantity of Line Sets
38AUZ 5 1
38AUD 6 2
Liquid Lift —
A liquid lift condition exists when the outdoor unit is located
below the indoor (evaporator) unit and liquid flows vertically
up in a portio n of the liquid line. The vertical column of
liquid reduces the available state point subcooling at the
evaporator coil’ s thermal expansion valve. This effect
reduces the length of liquid lift (feet of elevation ) that a
liquid line size can accommodate. Longer linear tube lengths
will also reduce the amount of liquid lift possible.
Check T ables 5 (38AUZ) and 6 (38AUD) for maximum
liquid lift capabilities for line sizes. Res elect the liquid line
tube size if necessary. If maximum available tube size
cannot provide the required lift distance on this installation,
relocate the outdoor unit to reduce the equivalent line length
or the lift requirement.
38AU