Hanbell ExP Series, Техническое руководство, Страница: 44 / 46

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5.2 regular check
a. To avoid refrigerant leakage, Hanbell strongly recommends using a gas detector and refer to ASHRAE 15 regarding standard
leakage rate.
b. Check whether clear frozen oil.
5.3 Troubleshooting
The table below shows some problem that might encounter in the jobsite during commissioning or upon operation of compressor.
This table will only serve as a guide for the Engineer to understand the situation once the problem occurred in the site.
PROBLEMS PROBABILITY CAUSES REMEDY / CORRECTIVE ACTION
Sudden trip of motor
thermistor / sensor
Low suction pressure cause low refrigerant flow rate Install liquid injection to motor coil
Refrigerant shortage Charge refrigerant
Suction filter clogged Clean filter
High suction temperature Install liquid injection to motor coil
High suction superheat Adjust the superheat less than 10°K
Unstable electricity system or failure Check electricity power supply
Motor overload
Bad motor coil causing temperature rising rapidly
Compressor unable to
load
Low ambient temperature or high oil viscosity. Turn on the oil heater before compressor start.
Capillary clogged. Clean or replace capillary
Modulation solenoid valve clogged or solenoid valve coil burnt. Clean / purge solenoid valve core or replace the solenoid valve coil
Internal built-in oil line clogged. Check and clean the compressor oil circuit
Piston stuck-up. Change piston or piston ring
Oil filter cartridge clogged. Clean oil filter (replace if needed)
Too small the high-low pressure differential. Minimum pressure differential is 4 bar. Consider to install an oil pump.
Compressor unable to
unload.
Modulation solenoid valve clogged or burnt. Clean or replace the solenoid valve
Piston rings worn off or broken, or cylinder damaged resulting leakage. Change piston (if cylinder damaged severely, change the cylinder)
Lubrication oil insufficient. Check the oil level of the compressor if enough, add some oil if necessary
Leakages at internal discharge cover plate end side. Check or replace the gasket and tighten the bolts.
Solenoid valve voltage misused. Check the control voltage
Piston stuck-up. Change the piston set, and check the cylinder and slide valve.
Capacity control logic unsuitable. Check
Poor insulation of
motor
1. Bad compressor motor coil.
Check the coil or change the motor stator
2. Motor power terminal or bolt wet or frosty.
3. Motor power terminal or bolt bad or dusty.
4. Bad insulation of magnetic contactors.
5. Acidified internal refrigeration system.
6. Motor coil running long time continuously under high temperature.
7. Compressor restart counts too many times.
Compressor starting
failure or Y- Δ starter
shifting failure
Slide valve piston unable to go back to its lowest % original position.
Check if the unloading SV is energized once the compressor shut down.
Unload the compressor before shot down.
Voltage incorrect. Check the power supply
Voltage drop too big when starting the compressor or magnetic contactor failure or phase failure.
Check the power supply and the contactor.
Motor broken down Change the motor
Motor thermister sensor trip. See “sudden trip of motor sensor” above
Incorrect supply power connection. Check and re-connect
Y- Δ timer failure. Check or replace.
Discharge or suction stop valve closed. Open the stop valve
Improper connection between node terminals of Y- Δ wiring. Check and re-connect the wiring
Rotor locked Check and repair
Earth fault Check and repair
Protection device trip Check
Abnormal vibration
and noise of
compressor
Damaged bearings. Change bearing.
Phenomenon of liquid compression. Adjust proper suction superheat
Friction between rotors or between rotor and compression chamber. Change screw rotors or/and compression chamber.
Insufficient lubrication oil.
Check the oil level of the compressor if enough, add some oil if necessary.
Loosen internal parts.
Dismantle the compressor and change the damaged parts.
Electromagnetic sound of the solenoid valve. Check
System harmonic vibration caused by improper piping system. Check the system piping and if possible improve it using copper pipe.
External debris fallen into the compressor.
Dismantle the compressor and check the extent of the damage.
Friction between slide valve and rotors. Dismantle the compressor and change the damaged parts.
Motor rotor rotates imbalance. Check and repair.
Compressor does not
run
Motor line open Check
Tripped overload Check the electrical connection
Screw rotors seized Replace screw rotors, bearings etc….
Motor broken Change motor.
High discharge
temperature
Insufficient refrigerant.
Check for leaks. Charge additional refrigerant and adjust suction superheat less
than 10°K
Condenser problem of bad heat exchange. Check and clean condenser
Refrigerant overcharge. Reduce the refrigerant charge
Air / moisture in the refrigerant system Recover and 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 damaged 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)
Compressor losses oil
Lack of refrigerant Check for leaks. Charge additional refrigerant.
Improper system piping Check and correct the piping or install an external oil separator
Liquid fills back Maintain suitable suction superheat at compressor