14
Table 4. Refrigerant Line Set Requirements
OUTDOOR UNIT
OUTDOOR UNIT
INDOOR UNIT
INDOOR UNIT
Maximum Line Set
Length
Maximum Line Set
Length
Maximum
Elevation -
Outdooor
Unit BELOW
Indoor Unit
Maximum
Elevation -
Outdooor
Unit ABOVE
Indoor Unit
Minimum Line Set
Length - 10 ft. (3m)
Minimum Line Set
Length - 10 ft. (3m)
Outside Unit BELOW Indoor Unit
Outside Unit ABOVE Indoor Unit
Do not allow for excess length of line sets to be left rolled up as part of the
required distance, or in general. This will also cause additional performance issues.
IMPORTANT
Each system size has a line set length and vertical elevation parameters.
System Size (KBtu)
Line Set Diameters (in.)
Maximum Elevation
Outdoor Unit BELOW
Indoor Unit - Feet
(Meter)
Maximum Elevation
Outdoor Unit ABOVE
Indoor Unit - Feet
(Meter)
Maximum Line
Set Length - Feet
(Meters)
Liquid
Gas
024
3/8
5/8
82 ft. (25 m)
82 ft. (25 m)
164 ft. (50 m)
036/048
3/8
5/8
98 ft. (30 m)
98 ft. (30 m)
213 ft. (65 m)
Leak Test and Evacuation
Air and moisture remaining in the refrigerant system will
have undesirable effects as indicated below:
• Pressure in the system rises
•
Operating current rises
•
Cooling or heating efficiency drops
• Moisture in the refrigerant circuit may freeze
• Water may lead to corrosion of parts in the refrigera-
tion system
The line set between the indoor and outdoor units
must be leak tested and evacuated to remove any non-
condensables and moisture from the system.
Leak Test
Use the following procedure to test for system leaks:
1. Connect the manifold gauge set and dry nitrogen gas
cylinder to the liquid and gas service ports.
2.
Open valve on nitrogen cylinder.
3. Pressurize the system per the pressure test
specifications in “Table 5. Pressure Test Specifications”.
4. Check that the system pressure remains stable. If
there is any movement check system for leaks.
5. After the system is found to be free of leaks:
• Close valve on nitrogen cylinder
• Relieve the nitrogen pressure by: loosening the
charge hose connector at the nitrogen cylinder
• When the system pressure is reduced to normal,
disconnect the hose from the cylinder
Table 5.
Pressure Test Specifications
Bar Psig
kPa
Duration
1
3
44
303
Minimum of 10 minutes
2
15
220
1517
Minimum of 10 minutes
3
32
470
3241
Minimum of 10 minutes
4
45
650
4482
1 hour. Stress test to prove the
integrity of the complete installation.
5
32
470
3241
24 hours. Lower system pressure
test, after confirmation No. 4 was
successfully completed.
IMPORTANT
Use only oxygen-free nitrogen (OFN).
Triple Evacuation Procedure
A Micron or Torr gauge must be used for this procedure.
1. Discharge the oxygen-free nitrogen and evacuate the
system to a reading of 8000 Microns (8 Torr) using all
service valves.
2.
Break the vacuum by allowing nitrogen into the port
connections (liquid and gas line pipes) until a positive
pressure is achieved.
3.
Evacuate the system to a reading of 5000 Microns (5
