8
Table 4 – Equivalent Lengths for Common Fittings (ft)
Nominal
Tube OD
Elbows
90
Std
90
Lrad 90
Street
45
Std
45
Street
3
/
8
1.3
0.8
2.2
0.6
1
1
/
2
1.4
0.9
2.3
0.7
1.1
5
/
8
1.6
1
2.5
0.8
1.3
3
/
4
1.8
1.2
2.9
0.9
1.5
7/8
2
1.4
3.2
0.9
1.6
1
1
/
8
2.6
1.7
4.1
1.3
2.1
1
3
/
8
3.3
2.3
5.6
1.7
3
1
5
/
8
4
2.6
6.3
2.1
3.4
2
1
/
8
5
3.3
8.2
2.6
4.5
Nominal
Tube OD
Tees
Branch
Flow
Straight-Thru
No Reduct
Reduce 25% Reduce 50%
3
/
8
2.6
0.8
1.1
1.3
1
/
2
2.7
0.9
1.2
1.4
5
/
8
3
1
1.4
1.6
3
/
4
3.5
1.2
1.7
1.8
7/8
4
1.4
1.9
2
1
1
/
8
5
1.7
2.3
2.6
1
3
/
8
7
2.3
3.1
3.3
1
5
/
8
8
2.6
3.7
4
2
1
/
8
10
3.3
4.7
5
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.
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 3 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 5 for maximum suction tube size for
38AUZD/E08 units at minimum load conditions. Consider
suction speed riser (reduced tube size for vertical segment
only) (see Fig. 4) or double suction riser arrangement (see
Fig. 5) if the planned suction tube size does not provide
necessary minimum flowrates for this riser.
Table 5 –
38AU Maximum Suction Pipe Size
Model:
Unit Size
Maximum Tube Size
38AUZD/E
08
1
5
/
8
CONDENSING
UNIT
20-FT (6.1 M) MAX
A
A - Suction Riser
Without
Trap
LEGEND
S - Suction Line to Condensing Unit
S
C12404
Fig. 4 -- Suction Line Piping -- Speed Riser
FROM
EVAPORATOR
A
A - Suction Riser
Without
Trap
B - Suction Riser
With
Trap
S - Suction Line to Condensing Unit
LEGEND
B
S
S
C12405
Fig. 5 -- Suction Line Piping -- Double Riser
Vertical Separation (outdoor unit above indoor unit) –
Vertical elevation difference of 200 ft (60 m) is permitted
when the outdoor unit (38AUZ) is located above the
indoor unit.
Step 6 — Complete Refrigerant Piping Connections
IMPORTANT:
Do not bury refrigerant 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.
38A
U
