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REFRIGERANT PIPING DESIGN
Device Connection Limitations
A single-zone system consists of one outdoor unit and one indoor unit. One of the most critical elements of a single-zone system is the
refrigerant piping. If the connection piping is not within allowable limits, there will be reliability, performance, noise, and vibration issues. The
table below lists pipe length limits that must be followed in the design of a Single Zone Four-Way Ceiling-Cassette refrigerant pipe system.
See paragraph below for calculating additional refrigerant charge necessary for longer piping lengths. Refer to the figures for maximum
length and elevation of piping.
Table 55: Single-Zone Four-Way Ceiling Cassette
System Model Name
Pipe Sizes
Pipe Length
(ELF = Equivalent
Length of Pipe)
Elevation
(All Elevation Limitations are
Measured in Actual Feet)
Additional Refrigerant Needed (oz/ft)
Figure 55: Typical LC098HV and LC128HV System Layout.
Max Length = A
Max Elevation = B
Indoor unit
66
A
B
Outdoor unit
Additional Refrigerant Charge
Each outdoor unit is factory charged (nameplate charge) for the
evaporator as well as a standard 24.6 foot line. Any time a line
set is used longer then the standard 24.6 foot line set length, the
refrigerant charge has to be adjusted.
The charge must be adjusted on 0.22 oz. or 0.43 oz. of R410A per
foot based on how many feet of piping are added. The factory charge
accommodates pipe lengths up to the standard length without
requiring refrigerant removal.
NOTE
Example:
78 | APPLICATION
Refrigerant Piping System Limitations.
Vapor
Liquid
Standard length (no add'l refrigerant)
Longest total equivalent piping length
Shortest total equivalent piping length
Distance between fittings and indoor or
outdoor units
If outdoor unit is above indoor unit
If outdoor unit is below indoor unit
Unit = Feet
Outdoor unit
66
A
B
Indoor unit
©
LC098HV, LC128HV
LC188HV, LC249HV
3/8
1/4
24.6 feet
66 feet
16.4
49 feet
49 feet
0.22
Figure 56: Typical LC188HV and LC249HV System Layout.
Max Length = A
Max Elevation = B
Indoor unit
164
A
B
Outdoor unit
Figure 57: Typical LC349HV and LC429HV System Layout.
Max Length = A
Max Elevation = B
Indoor unit
246
A
B
Outdoor unit
LC369HV, LC429HV
5/8
5/8
3/8
3/8
24.6 feet
24.6 feet
164 feet
246 feet
16.4
16.4
98.4 feet
98.4 feet
98.4 feet
98.4 feet
0.43
0.43
Unit = Feet
Outdoor unit
164
A
B
Indoor unit
Unit = Feet
Outdoor unit
246
A
B
Indoor unit
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