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4.7
Pipe Installation
Installation of the outdoor air-cooled condenser should only be done by a qualified refrigeration mechanic
familiar with this type of work. Many service problems can be avoided by taking adequate precautions to
provide an internally clean and dry system and by using procedures and materials that conform to
established procedural standards.
1.
Materials
•
Use clean, dehydrated, refrigeration-grade copper tubing for all refrigerant lines. Hard drawn tubing should be
used where no appreciable amount of bending around pipes or obstructions is necessary. If soft copper tubing
must be used, care should be taken to avoid sharp bends which may cause restrictions and excessive refrigerant
pressure drops.
•
Use long radius elbows wherever possible with one exception - short radius elbows should be used for any traps
in the hot gas riser.
•
Braze all copper to copper joints with a phosphorus-copper alloy material such as Silfos 5 or equivalent. Do not
use soft solder.
•
During brazing operations flow an inert gas, such as nitrogen, through the lines to prevent internal oxidation
scaling and contamination.
•
Support refrigeration lines at intervals with suitable hangers, brackets or clamps.
•
Pack glass fiber insulation and a sealing material around refrigerant lines, where they penetrate a wall, to
reduce vibration and to retain some flexibility.
•
The liquid line and discharge line should not be in contact with one another. If the installing contractor must tie
these lines together because of an installation requirement, the contractor must insulate them from each other
to prevent heat transfer. Because the discharge line is hot during system operation, precautions should be
taken to avoid personnel injury.
2.
Sizing
•
The lines must be sized and routed so that oil is carried through the system. Using smaller lines than
recommended will give excessive pressure drops, resulting in reduced capacity and increased power
consumption. Oversized lines could result in an oil flow problem within the system and possible compressor
damage.
•
Excessive pressure drops in the liquid line may cause flashing of the refrigerant and a loss of a liquid seal at the
expansion valve inlet. A reduction in capacity may then occur because the presence of gaseous refrigerant will
partially block the expansion valve. Using hot gas and liquid line sizes recommended in the Air Cooled
Condenser section for these units and the proper system refrigerant charge will prevent this problem.
•
Discharge lines should be designed to prevent condensed refrigerant and oil from draining back to the
compressor during OFF cycles.
NOTE
The size of the Copper
Pipe: 2pcs of 25mm, 2pcs
of 19mm
