Carrier 38AUM Series, Инструкция по установке, эксплуатации и обслуживанию, Страница: 10 / 44

Check 38AUM Model with Evaporator Coil Connections
Confirm before installation of unit that the evaporator coil connections are consistent with this 38AUM model.
Determine Refrigerant Line Sizes
Select the recommended line sizes for 38AUMZ and 38AUMD unit from the appropriate tables. Determine the linear
length of interconnecting piping required between the outdoor unit and indoor unit (evaporator). Consider and identify
also the arrangement 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. Determine equivalent line length adjustments for path and
components and add to linear line lengths. See Equivalent Lengths for Common Fittings (EN units), 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.
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
NOTE
: Equivalent line lengths will vary based on tube diameter. Calculate equivalent line length for each pipe by
adding equivalent length adjustments to linear lengths for each pipe. Enter the appropriate table to select the
recommended line sizes.
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 portion 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 Table
Piping Recommendation for maximum liquid lift capabilities for line sizes. Reselect 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.
Suction Riser
A suction riser condition exists when the outdoor unit is located above the indoor (evaporator) unit and suction vapor
must flow vertically up to return to the compressor. Oil return is a concern when the suction tube size is too large to
produce the minimum refrigerant velocity to ensure oil return at minimum load conditions. Check Table 38AUM
Maximum Suction Pipe Size for maximum suction tube size for 38AUM units at minimum load conditions. Consider
suction speed riser (reduced tube size for vertical segment only) or double suction riser arrangement if the proposed
suction tube size does not provide necessary minimum flowrates for this riser.
38AUM Maximum Suction Pipe Size
Model: Unit Size Maximum Tube Size
38AUMZ
07 1 – 3/8
08 1 – 5/8
38AUMD
12 1 – 3/8
14 1 – 3/8
16 1 – 3/8
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
Model: Line Sizes Table Quality of Line Sets
38AUMZ 5 1
38AUMD 6 2
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