Screw compressor
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Causes of faults in slide valve-controlled twin-screw compressors. Fault symptoms: The opening degree of the slide valve varies each time the compressor is started; sometimes it can reach 100% of its maximum opening, while other times it only reaches 20%. However, the cooling load of users remained essentially unchanged. Seeking advice!
Check whether the spool indicator signal is correct? Does the current of the motor change in sync with the valve spool position? How is the opening degree of the flash valve changing?
Is the spool screw stuck?
The operation of the slide valve is related to temperature
Have there been any changes in operating conditions, such as inlet temperature and pressure, outlet pressure, and the efficiency of the condenser in performing condensation?
Observe whether there are any changes in the motor current as well as the suction pressure and exhaust pressure; if no changes are observed, it is recommended to check whether the spool valve probe is functioning properly
The opening degree of the slide valve is adjusted based on the cooling capacity and load; if there are no alarms from the unit, there’s no need to worry too much
Is the operating current of the compressor normal? Are there any large fluctuations? If the current doesn’t change, it’s a problem with the spool position sensor
I think it’s probably a problem with the spool position sensor, as the current changes with variations in load. But this is a vicious cycle: when there is a problem with the slide valve, it opens wider, which increases the load on the unit, resulting in a poorer cooling effect. As a result, users demand more refrigerant, which in turn increases the load on the unit further.