Pump failure is one of the most common mechanical issues encountered in commercial and industrial chiller systems. These pumps are responsible for circulating chilled water or glycol throughout the system. When they fail, cooling performance can drop rapidly or stop altogether.
Understanding the causes, consequences and repair options for pump failure is key to minimising downtime and preventing wider system damage.
Signs Your Chiller Pump May Be Failing
Pump problems often start subtly before becoming more serious. These are some of the most common warning signs:
- The flow rate begins to drop, with poor temperature control at the far end of the circuit
- You hear unusual noises, such as grinding or rattling, from the pump housing
- The pump becomes unusually hot or vibrates more than normal
- Pressure readings are unstable or show a consistent drop
- Low flow or pressure alarms appear on the control panel
- Seal failure causes visible leaks around the pump casing
Common Causes of Chiller Pump Failure
Pump failure is rarely the result of a single issue. More often, it is the outcome of gradual wear combined with system imbalance. One of the most common causes is mechanical seal degradation, often from poor lubrication, water chemistry issues or particulate damage. Bearing wear, misalignment or overworked motors can also lead to overheating or seizure.
Electrical faults are another risk, particularly when control signals are lost or when power supply irregularities cause overheating. In glycol systems, incorrect fluid concentration can also lead to pump stress, particularly in colder months when fluid becomes more viscous.
Troubleshooting and Repair Process
Once a pump fault has been confirmed, engineers should follow a structured diagnostic and repair sequence.
1. Initial System Assessment
Engineers begin by confirming whether the fault lies with the pump or another part of the system. Flow sensors, pressure readings and motor current levels are checked alongside system alarms.
2. Mechanical Inspection
The pump is inspected for bearing wear, misalignment, shaft seal damage and impeller degradation. Any signs of cavitation or blockage are addressed at this stage.
3. Electrical Testing
Control signals, motor windings and power supply integrity are checked. If the motor is burned out, it is either rewound or replaced, depending on age and availability.
4. Operational Verification
Once repairs are complete, the pump is tested under normal operating conditions to confirm flow rates, noise levels and system pressures are within range.
If a replacement is required, the new pump must be properly matched to the system’s hydraulic design, something our engineers assess carefully on site.
Repair or Replace? What to Consider
While certain pump issues can be resolved with part replacements or servicing, it is not always the most economical route. If the pump is part of an older system with recurring faults or poor overall efficiency, replacing the entire chiller unit may be more cost-effective long term.
Modern chillers are quieter, more efficient and compatible with advanced control systems and newer refrigerants. We offer a full range of replacement chiller systems tailored to each site’s load profile and application.
Our team will always evaluate the condition of the wider system and advise whether repair or full replacement is the more reliable option.
Why Regular Maintenance Makes a Difference
Scheduled chiller maintenance is the best way to prevent pump failure. During a service, engineers check for signs of wear, test flow rates, inspect seals and bearings and verify pressure performance. Early detection of flow issues or component stress can prevent system-wide faults and emergency shutdowns.
