www.poolpak.com | 800-959-772546 | MPK Series - Installation, Operation and Maintenance
Field Installed Piping
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 standards.
PIPING GUIDELINES
The following piping recommendations are intended for use as a general guide. For more complete information,
refer to the latest ASHRAE Handbook.
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.
• PoolPak units do not utilize compressors with unloading stages. Consequently, double hot gas risers are not
needed for reduced load conditions as refrigerant flow rates will not fall below minimum velocities necessary
to carry oil up through the discharge line.
• A field provided, field installed liquid line filter-drier is required in the field piping adjacent to the PoolPak unit
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. Oversizing 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. Proper sizing and charging of the lineset will prevent this problem.
• Discharge lines should be designed to prevent condensed refrigerant and oil from draining back to the
compressor during OFF cycles. Use the following guidelines:
• The highest point in the discharge line should be above the highest point in the condenser coil.
• The hot gas line should loop toward the floor if the condenser is located above the PoolPak unit, especially if the
hot gas riser is long.
• For refrigerant line sizing for an Air Cooled Condenser (ACC) where the lineset length is less than 100 feet or the
ACC location is less than 50 feet higher or 20 feet lower than the unit, use the below Table 4-1.
• ACC line lengths beyond the above limits will void warranty unless written approval is obtained from the factory
PRIOR to installation and startup.
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