Hanbell RC2-AV Series, Manual

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PROBLEMS POSSIBLE CAUSES REMEDY / CORRECTIVE ACTION
Abnormal vibration and
noise of compressor
Liquid compression Adjust proper suction superheat
Friction between rotors or between rotor and
compression chamber
Change screw rotors or compression chamber or both.
Insufficient lubrication oil
Check the oil supply of the compressor is enough, add some
oil if necessary
Loose internal parts Dismantle the compressor and tighten/change loose parts
System harmonic vibration caused by improper piping
system
Check the system piping and if possible replace steel pipe by
copper pipe
External debris fallen into the compressor
Dismantle the compressor and check the damage. Clean and
polish rotor and chamber surfaces. Replacement might be
needed depending on damages.
Friction between slide valve and rotors Dismantle the compressor and change damaged parts
Motor rotor rotates imbalance Check and repair
Motor line open Check
Start-up difficulties
Tripped overload Check the electrical connection
Screw rotors seized Replace screw rotors, bearings etc…
Broken motor Change motor
Insufficient refrigerant
Leakage test. Charge additional refrigerant and adjust
suction superheat less than 10K
High discharge temperature
Poor heat exchange in condenser Check and clean the condenser
Refrigerant overcharge Reduce the refrigerant charge
Air/moisture in refrigerant system Recover, purify refrigerant and vacuum system
Improper expansion valve Check and adjust proper suction super heat
Insufficient lubrication oil Check the oil level and add oil
Damaged bearings
Stop the compressor and change the bearings and other
necessary parts
Improper Vi value Change the slide valve
No system additional cooling (Liquid injection or oil
cooler)
Install additional system cooling (liquid injection or oil cooling
or both base on working condition limitation)
Lack of refrigerant Check for leaks. Charge additional refrigerant
Compressor losses oil
Improper system piping
Check and correct the piping or install an external oil
separator
Liquid fills back Maintain suitable suction superheat at compressor
Lack of refrigerant Check for leakage. Charge additional refrigerant
Low suction pressure
Evaporator dirty or iced Defrost or clean coil
Clogged liquid line filter drier Replace the cartridge
Clogged suction line or compressor suction strainer Clean or change suction strainer
Expansion valve malfunctioning Check and reset for proper superheat
Condensing temperature too low Check means for regulating condensing temperature
Note: Replacements of compressor parts should be performed by a qualified / certified serviceman with full knowledge
of HANBELL screw compressors or HANBELL service engineers.