Multi F Installation Manual

35
Refrigerant Piping Connections
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MULTI
F
MAX
MULTI
F
h2
h1
A
B
REFRIGERANT PIPING CONNECTIONS
Multi F Outdoor Unit Piping Length and
Elevation Limitations
Piping Length and Elevation Limitations
One of the most critical elements of Multi F and Multi F MAX systems is the refrigerant piping. The tables on the next few pages list pipe
length limits that must be followed in the design of Multi F and Multi F MAX refrigerant pipe systems.
Figure 41: Multi F Refrigerant Piping System
Limitations (LMU18CHV Example).
Outdoor Unit Model (Btu/h)
LMU18CHV /
18,000
LMU24CHV /
24,000
LMU30CHV /
30,000
LMU36CHV /
36,000
Max. Total System Piping Length (ft.)
164
A+B
246.1
A+B+C
246.1
A+B+C+D
246.1
A+B+C+D
Min. Length for One Branch (ft.) 9.8 9.8 9.8 9.8
Max. Length for One Branch (ft.) 82 82 82 82
Max. Elevation Between Each Indoor Unit
and Outdoor Unit (h1)
49.2 49.2 49.2 49.2
Max. Elevation Between Indoor Units (h2) 24.6 24.6 24.6 24.6
Max. Combination of Indoor Units 24,000 33,000 40,000 48,000
Table 19: Multi F Refrigerant Piping System Limitations.
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Max. 49.2 feet
Max. 24.6 feet
A
B
C
D
Multi F System Example
Example: LMU36CHV outdoor unit with four (4) indoor units
connected.
ODU: Outdoor Unit.
IDU: Indoor Unit.
A, B, C, D: Pipes from Outdoor Unit to Indoor Unit.
Device Connection Limitations
• The minimum number of connected and operating indoor units to Multi F / Multi F MAX systems is two, taking into consideration the
minimum combination ratio.
• The maximum number of indoor units for each Multi F / Multi F MAX heat pump systems is:
LMU18CHV = 2 LMU24CHV = 3 LMU30CHV = 4 LMU36CHV = 4 LMU480HV = 8 LMU540HV = 8 LMU600HV = 8
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Table 20: Equivalent Piping Length for Elbows, Y-branches,
and Branch Distribution Units.
1
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Component
Size (Inches)
1/4 3/8 1/2 5/8 3/4
Elbow (ft.) 0.5 0.6 0.7 0.8 1.2
Y-Branch Kit (ft., Multi F MAX
systems only)
1
1.6
Branch Distribution Unit (ft.,
Multi F MAX systems only)
8.2
Using Refrigerant Components
Field-supplied elbows are allowed as long as they are designed for use with
R410A refrigerant. The designer, however, should be cautious with the quantity
and size of fittings used, and must account for the additional pressure losses in
equivalent pipe length calculation for each branch. The equivalent pipe length of
each elbow must be added to each pipe segment.