Comprehensive Fault Diagnosis Guide for Full Range CHANUN Rotary Screw Compressors

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Comprehensive Fault Diagnosis Guide for Full Range CHANUN Rotary Screw Compressors

Release time:

2026-07-24

Factory maintenance teams often encounter diversified abnormal faults on rotary screw compressors, including unstable discharge pressure, excessive operating temperature, abnormal vibration noise, lubricant deterioration and air end abrasion. Many technicians only replace damaged spare parts temporarily without systematic root cause analysis, leading to recurring failures and long-term hidden operation costs. CHANUN provides a unified diagnosis logic matching its full 2.2kW–75kW compressor lineup, covering mechanical, electrical, cooling and control system faults, combined with targeted elimination schemes and standardized after-sales guarantee rules.

1 Classification of Common Recurring Faults of Rotary Screw Compressors

Based on tens of thousands of on-site maintenance records from global service outlets, all typical compressor failures fall into four core categories, which we sort by occurrence frequency:

1.1 Pressure Abnormality Faults

This category includes two opposite failure manifestations: insufficient stable air output and overpressure frequent shutdown.

Low discharge pressure: Long-term filter blockage, aging minimum pressure valve, air pipeline leakage or mismatched VSD parameter settings will cause FAD loss, failing to meet the continuous gas demand of production equipment such as laser cutting and spraying machines.
Frequent overpressure trip: Damaged pressure sensor, failure of pressure relief valve and unreasonable upper/lower pressure difference setting lead to frequent automatic shutdown of the unit, disrupting continuous production rhythm.

1.2 Overheating & Cooling System Failures

Excessive operating temperature is a major factor shortening the service life of air end and lubricating oil, with multiple inducing factors:

Heat exchanger blockage: Dust, metal powder and oil dirt adhere to the surface of air-cooled radiator or water-cooled condenser, reducing heat exchange efficiency sharply.
Cooling fan malfunction: Fan motor burnout, aging fan bearings or abnormal fan control signals cause insufficient forced heat dissipation.
Lubricant shortage or oil degradation: Long-term failure to replace lubricating oil, oil pipeline blockage and oil leakage will break the heat transfer cycle of the unit.
Ambient heat accumulation: Equipment room without ventilation, multiple units operating closely together result in poor ambient heat dissipation.

1.3 Vibration & Abnormal Noise Faults

Continuous abnormal vibration and noise reflect loose or worn internal mechanical structures, which cannot be ignored:

Unbalanced air end rotor: Long-term oil shortage operation leads to uneven rotor abrasion, generating high-frequency rumble noise.
Loose fixed components: Aging shock absorption pads, loose base bolts and detached pipeline brackets amplify equipment vibration during operation.
Bearing wear of fan and motor: Metal friction sound appears when rolling bearings reach the end of service life; if not replaced in time, it will trigger motor stalling.
Foreign matter entering the compression cavity: Broken filter fragments fall into the air end, producing irregular collision noise.

1.4 Electrical & Intelligent Control System Faults

Most intermittent random faults originate from control circuits and electrical components:

Inverter alarm and shutdown: Poor heat dissipation of VSD module, unstable input voltage and damaged current sensor trigger overload, overheating and phase loss alarms.
Unresponsive touch control panel: Loose communication wiring, aging display module and program parameter disorder cause failure to adjust pressure and load.
Motor startup failure: Contactor ablation, damaged thermal protector and insufficient buffer voltage lead to failure to start normally after power on.

2 Standard Four-Step Systematic Fault Diagnosis Process

CHANUN summarizes a universal inspection flow applicable to all models in its full product line, avoiding blind disassembly and repeated component replacement:

Step 1 Collect Complete Operating Data Before Shutdown

Record real-time operating parameters through the unit’s HMI control screen: stable discharge pressure, oil temperature, motor operating current, running load rate and historical alarm codes. Meanwhile record workshop environment: ambient temperature, relative humidity, daily continuous running hours and supporting post-processing equipment operating status. Historical data can directly narrow down the fault range without disassembly.

Step 2 External Visual & Functional Inspection

Carry out full external inspection without disassembling core components:

Check all air filters, oil filters and separator cores for blockage and aging;
Inspect oil pipelines, air pipelines and all sealing joints for oil or air leakage;
Observe the operating state of cooling fan, drain valve and pressure relief valve;
Test the flexibility of touch screen, remote signal receiving and startup response speed.

Step 3 Layered Disassembly Internal Inspection (Targeted According to Alarm Codes)

Locate suspected assemblies according to fault types summarized in the first chapter for targeted disassembly:

Pressure faults: Focus on minimum pressure valve, pressure sensor and air receiver pipeline joints;
Overheating faults: Dismantle and clean heat exchanger, check oil circulation pipeline and fan assembly;
Vibration & noise faults: Inspect shock absorption structure, motor bearings and air end internal rotor clearance;
Electrical faults: Detect contactors, wiring terminals, inverter modules and sensor wiring tightness with a multimeter.

Step 4 Simulated Load Verification After Maintenance

After replacing faulty accessories or adjusting abnormal parameters, run the unit under actual production load for no less than 2 consecutive hours. Monitor all operating indicators in real time to confirm that alarm codes no longer appear, pressure, temperature and noise return to the standard range, so as to judge whether the fault is completely eliminated.

3 Root Cause Permanent Elimination Solutions for Major Faults

3.1 Solutions for Pressure Instability

Pipeline leakage: Replace aging sealing gaskets and fasten loose pipeline joints; add pressure monitoring points for long-distance air supply pipelines;
Blocked filter elements: Follow the official maintenance cycle to replace original filter cores; install pre-filter devices for high-dust workshops;
Abnormal pressure valve: Replace worn minimum pressure valve and pressure relief valve with CHANUN original parts, and recalibrate pressure difference parameters on the control panel.

3.2 Overheating Fault Optimization Measures

Heat exchanger blockage: Clean radiator surface with compressed air every month; use water washing for severe oil dirt accumulation (cut off power in advance);
Cooling fan failure: Replace fan motor and bearings regularly, optimize fan automatic startup and shutdown temperature threshold;
Lubrication failure: Strictly use CHANUN special anti-oxidation lubricating oil, replace oil every 2000 working hours, and clean oil filter regularly;
Environmental heat accumulation: Increase ventilation fans in the equipment room, reserve independent heat dissipation intervals between multiple compressors.

3.3 Vibration & Noise Control Schemes

Rotor unbalance: Replace worn air end bearing assembly, carry out dynamic balance calibration of the rotor; avoid long-term low-load idle operation;
Loose fixing parts: Replace aging shock absorption pads, retighten all base and pipeline fixed bolts every six months;
Foreign matter intrusion: Upgrade high-efficiency primary air filters to prevent debris from entering the compression cavity.

3.4 Electrical & Control System Maintenance Standards

Inverter failure: Clean VSD heat sink regularly, configure stable voltage regulator equipment for factories with fluctuating grid voltage;
Control panel malfunction: Reconnect loose communication cables, restore factory settings and re-import standard operating parameters;
Motor startup failure: Replace ablated contactors and aging thermal protection components, check three-phase power supply balance before each startup.

4 Full-Series After-Sales Support & Warranty Explanation

All CHANUN rotary screw compressors from 2.2kW to 75kW adopt unified manufacturing standards and accessory general specifications, which greatly reduces the difficulty of cross-model maintenance for technicians.

Original spare parts supply: Global authorized dealers and domestic 200+ service outlets stock complete original filters, valves, bearings and electrical components, realizing rapid replacement;
Standard warranty scope: The air end enjoys a 2-year official warranty against manufacturing defects; electrical parts, heat exchange assemblies and control systems are covered by a 12-month warranty under standardized operation and maintenance;
On-site service support: Overseas customers can apply for remote technical video guidance; domestic factories enjoy 24-hour emergency on-site fault diagnosis service.

Key Warranty Exclusion Reminders

All faults caused by human operation errors are not included in the free warranty, including the use of non-original lubricants and filter elements, overpressure long-term overload operation, failure to perform maintenance according to the cycle, and unmodified disassembly of core components without authorization.

5 Daily Maintenance Checklist to Reduce Fault Frequency

Regular standardized maintenance can cut compressor failure rate by more than 70%:

Daily: Check unit operating noise, oil level and pressure display; empty condensed water of air receiver tank;
Weekly: Clean radiator surface, inspect all pipeline joints for leakage;
Monthly: Test the automatic operation of cooling fan and drain valve; check filter blockage degree;
Every 2000 working hours: Replace lubricating oil, oil filter, air filter and separator core, and calibrate control parameters.

Closing Summary

Most frequent compressor faults are not sudden quality defects, but the cumulative result of irregular operation and delayed maintenance. This multi-dimensional systematic diagnosis guide adapts to all models of CHANUN full product lineup, helping maintenance staff quickly locate fault sources and formulate permanent elimination plans. Factories in need of detailed fault code manuals and maintenance operation videos can visit the official international website www.chanuncompressor.com to download complete technical materials or contact global authorized service engineers for one-to-one technical consultation.