Understanding compressor failures By Eamonn Ryan Root causes and best practices for reliable operation.
INCORPORATING COLD CHAIN
NETWORKING
COLD LINK AFRICA PUBLISHED BY Interact Media Defined( Pty) Ltd 13A Riley Rd, Bedfordview, 2007, South Africa PO Box 695, Edenvale, 1610 Tel: + 27( 0) 11 579 4940 Web: www. interactmedia. co. za
PUBLISHING UNIT LEAD: Dale Macnamara sales @ interactmedia. co. za
EDITOR: Eamonn Ryan eamonn @ interactmedia. co. za
Understanding compressor failures By Eamonn Ryan Root causes and best practices for reliable operation.
CONSULTING EDITOR: John Ackermann
ADVERTISING SALES External sales: Dale Macnamara sales @ interactmedia. co. za
SUBSCRIPTIONS: Ralph Shongwe | ralph @ interactmedia. co. za
SUB-EDITOR: Megan O ' Connor megan @ interactmedia. co. za
DESIGN AND LAYOUT: Ruan Coetzee ruan @ interactmedia. co. za
PROCESS CO-ORDINATOR: Royce Headger royce @ interactmedia. co. za
MANAGEMENT Finance / operations: Sean Macnamara sean @ interactmedia. co. za Finance: Laetitia Arnott | laetitia @ interactmedia. co. za
PRINTING: TYPO
DISTRIBUTION: distribution @ interactmedia. co. za
CIRCULATION: Jul- Sep 2025 Print: 2 416 | Online: 1 401 | Total: 3 817
ENVIRONMENT-FRIENDLY PRINTING: All paper is sourced from the Forest Stewardship Council and Chain of Custody-certified suppliers. All wastepaper from the plant is recycled. All used plates are recycled. All new printing equipment is purchased for low energy-consumption levels and low volatile organic-compound emissions.
DISCLAIMER: While every reasonable precaution has been taken to ensure the accuracy of the advice and information given, neither the editor, publisher, proprietor, staff, nor any official body represented or published in this issue, will accept responsibility for any damages, loss, injuries, or false claims that may arise or be made in the content. Including but not limited to any references to gender, religion, politics, ethnicity, or personal preferences of any editorial contribution whether an industry expert, advertiser through sponsored or paid content or contract writer. We subscribe to the Code of Conduct of the Advertising Regulatory Board( info @ arb. co. za) and the Press Ombudsman( see below). Disclaimers by individual companies are hereby overridden by this disclaimer.
COPYRIGHT: Reproduction of any of the content and photographs is expressly forbidden in terms of the Copyright Act of 1987 with all amendments. All requests to reproduce must be made in writing to the publisher and such confirmation must be given in writing before proceeding. A copy of where the reproduction was published must be supplied to the publisher at the above address. All publication and exhibition titles are registered as trademarks in terms of the Trademarks Act of 1993 and are held by Interact Media Defined( Pty) Ltd, Reg No 2014 / 092774 / 07.
PRESS OMBUDSMAN: This publication has committed itself to maintain the highest standards of journalism as embodied in the Press Code of Professional Practice. If you believe we have failed to report news and comment accurately, honestly and fairly, you may lodge a complaint with the Press Ombudsman either by email, letter, or by telephoning the office for the procedure to be followed. Tel: + 27( 0) 11 484 3612 / 8. Email: enquiries @ ombudsman. org. za Website: www. presscouncil. org. za for the press code and / or the complaints form.
OFFICIAL PUBLICATION
When measurement matters
On 11 November 2025, the SAIRAC Cape Town Centre hosted a technical talk by Grant Truebody, general manager at Million-Air Services – refrigeration and HVAC compressor specialists. With more than 20 years of experience in the industry, he brings expert knowledge in compressor failure diagnostics, system fault finding and troubleshooting, including experience in ammonia, CO2 systems, and technical training.
Over the course of the session, Truebody examined common causes of compressor breakdowns, including electrical, mechanical and system-related issues, and emphasised the importance of commissioning, preventative maintenance and root cause analysis. This article distills the key lessons from the session, providing practical guidance for technicians, engineers and end-users on diagnosing failures, optimising system performance and extending the operational life of compressors.
" Compressor failures are some of the most common and costly problems we face in industrial refrigeration systems. While the immediate result is usually downtime, the real causes are often misunderstood. From my experience, a compressor rarely fails on its own; more often, it’ s the system, the installation or operational practices that set the stage for the failure,” says Truebody.
1. TYPES OF COMPRESSOR FAILURES: ELECTRICAL, MECHANICAL AND SYSTEM- RELATED
Electrical failures account for a significant proportion of compressor issues. Typical scenarios include:
• Complete winding burnout: Here, the insulation melts, copper darkens and the motor is entirely damaged. Causes may include low voltage, short cycling, loose connections or unbalanced voltage.
• Single-phase loss: If one phase is lost, the remaining phases overwork, causing overheating in two of the three windings. Identifying this requires checking fuses, contactors and connections.
• Half-winding burnout: In systems with multiple windings, a delayed or failed phase can lead to one half of the winding burning while the other remains intact. Delays in oil or contactor activation are often culprits.
“ Mechanical failures usually start with overheating or lubrication problems. High discharge temperatures, blocked condensers or poor airflow can all degrade the oil’ s viscosity, which then damages bearings, rods and pistons. When you open up a compressor, a visual inspection often tells the story – blackened components, scorched rings, burned bearings – these are clear signs of overheating or insufficient lubrication,” explains Truebody.
“ System-related failures, on the other hand, are often more subtle but just as critical. Excessive moisture can lead to coppering inside the system. Liquid slugging can tear apart reed valves or pistons. Even poorly designed or misaligned mounts can create vibration, accelerate wear and eventually cause failure.
“ The key point to understand is that the compressor is rarely the root cause – it’ s usually the symptom. Consequently, simply replacing a
Grant Truebody, general manager at Million-Air Services, commencing his presentation.
failed unit without addressing the underlying system issues almost guarantees repeated failures. In fact, statistically, a new or refurbished compressor is four times more likely to fail than the original factory-installed unit if the system problems aren’ t corrected.”
2. VISUAL DIAGNOSIS: WHAT COMPONENT DAMAGE TELLS YOU
Field technicians can often determine the nature of a failure through careful inspection:
• Overheated components: Blackened pistons, scorched bearings and darkened valve plates indicate insufficient lubrication or high discharge temperatures.
• Liquid-related damage: Clean, undarkened components with broken reed valves often signal liquid slugging.
• Moisture contamination: Coppering on internal components points to residual moisture in the system – often due to poor evacuation during installation, open-system flushing or minor leaks.
Truebody adds:“ Understanding these visual clues is critical. When you can interpret burnt, blackened or coppered components, you’ re able to link the damage you see back to the underlying system problem. This reduces guesswork and ensures that any corrective action you take actually addresses the root cause, rather than just treating the symptom.”
3. THE ROLE OF INSTALLATION AND COMMISSIONING
Proper installation and commissioning are critical to compressor longevity. A rushed or incomplete start-up can mask problems that manifest as early failures. Commissioning should include:
• Pulling a proper vacuum to remove all moisture.
• Checking refrigerant charge and oil levels, verifying OEM-specified oils.
• Verifying superheat and subcooling settings to prevent overheating.
• Conducting electrical checks: voltage, current, insulation resistance and rotation direction.
• Testing safety devices: high- and lowpressure cutouts, oil failure switches and vibration mounts.
• Recording baseline operating data: pressures, temperatures and amperage readings.
“ A thorough commissioning process isn’ t something you rush through. For a small system, it can take a full day, and for more complex plants several days. Done properly, commissioning prevents early failures, reduces warranty claims and gives you baseline data you can use for future troubleshooting. It sets the system up for long-term reliability from day one, ensuring that both the mechanical and electrical components are operating exactly as they should.”
4. MAINTENANCE: PROTECTING CAPITAL EQUIPMENT
Even the best commissioning cannot compensate for neglect. Preventative maintenance is essential to preserve system integrity over the life of the compressor. Key maintenance practices include:
• Routine inspections: Check oil levels, colour and condition. Conduct oil analysis to detect moisture or debris.
• System integrity checks: Monitor pressures, refrigerant levels and superheat. Detect slow leaks or changes in operating parameters.
• Mechanical monitoring: Check alignment, vibration mounts and bearing conditions. Verify HPLP switches and other safety devices are properly mounted and functional.
• Electrical checks: Test insulation resistance and winding condition over time, noting trends that may indicate emerging problems.
“ Preventative maintenance is what turns unplanned breakdowns into planned interventions,” says Truebody.“ By regularly inspecting your system, monitoring oil quality, checking pressures and ensuring everything is operating within specification, you reduce downtime and protect your expensive components. Organisations that implement systematic on-site monitoring – like those offering‘ cooling-as-a-service’ – can extend the life of compressors by decades while keeping operations running efficiently. It’ s not just about fixing problems; it’ s about preventing them before they happen and keeping the entire system healthy over the long term.”
All images supplied by SAIRAC Cape Town Centre
March / April 2026 www. coldlinkafrica. co. za COLD LINK AFRICA
5