Refrigerant Piping Connection; Refrigerant & Charging - Pioneer KFDH075UW Technical Manual

Unit Installation Unit Installation
Field Copper Tubing Connection
To ensure satisfactory operation and performance, the following points should be noted for the field
tubing arrangements of the complete refrigerant cycle.
a) Liquid loops or oil traps must be provided according to the position of the outdoor and the indoor
units (depending on whether the indoor unit is above or below the outdoor unit).
b) Field supplied filter drier must be installed as close to the expansion valve(s) of the indoor
unit (evaporator) as possible.
c) Field supplied sight glass must be assembled and mounted next to filter dryer.
d) Pipe size shall be followed as listed in page
Caution:
• During the preparation, piping shall be properly covered to avoid the containmination of the system.
• Both indoor and outdoor are brazed connection.
Warning:
• Make sure there is no flammable gas at the surrounding before the brazing work started.
• DO NOT charge in flammable gas.
Maximum tube length and Maximum number of Bends
When the pipe is too long, the required refrigerant quantity increases, both the capacity and
reliability of compressor will drop.
When the number of bends increases, refrigerant flow resistance increases, thus lowering the cooling
capacity; the excessive pressure drop might eventually cause the failure of compressor.
If height difference of evaporator and condenser is excessive, this will retard the compressor oil return
and affecting the compressor efficiency
Always choose the shortest piping path with minimum bends.
Cautions: All units installation length
Max elevation
Max total equivalent length 35M
Max bends
For operation safety, accumulator is recommended to be added for any installation more than 30m in
length length
Field Charging & Refrigerant Handling
Scroll compressors have a very high volumetric efficiency and quickly pump a deep vacuum if there is
insufficient refrigerant in the system or if refrigerant is added too slowly. Low suction pressure will lead
to high discharge temperatures.
This process will casue the scrolls are not being well-lubricated eventually leads to high friction
between the scroll flanks and tips and generates additional heat.
This will cause damage to scroll bearing which can occur in less than one minute. But the failure might
occur only in later of time after charging.
Other typical field charging problems include undercharging, overcharging, moisture or air in the
system etc. In time each one of these problems can cause compressor failure.
Equipment
Minimal equipments are required for field charging. to do a satisfactory job is :
Set of service gauges
,
20M
8
Hoses , Vacuum pump,
Scales Thermometer
,
Charging Cylinder
Vacuum gauge