Chillers are among the most capital-intensive and operationally critical pieces of equipment in a commercial or industrial facility. When they work correctly, they’re invisible. When they don’t, the consequences spread quickly: production shutdowns, equipment damage, occupant discomfort, and repair bills that reflect the equipment’s complexity. For Indiana facilities operating commercial chiller systems, understanding the technology, the maintenance requirements, and what to look for in a chiller service provider is essential to protecting one of your facility’s largest mechanical investments.
This guide covers the fundamentals of commercial chiller systems, common problems, maintenance best practices, and how to evaluate repair versus replacement decisions that every facility operating aging cooling equipment will eventually face.
What Are Commercial Chiller Systems?
A chiller is a mechanical system that removes heat from a liquid, typically water or a water-glycol mixture, and rejects it to the air or to water outside the facility. The chilled liquid is then circulated through the building or process to absorb heat from the spaces or equipment being cooled before returning to the chiller to be re-cooled.
This indirect cooling approach makes chillers particularly well-suited to large commercial and industrial applications in which a central cooling plant serves multiple zones or processes via a distribution network. Unlike direct-expansion systems that cool air directly, chiller systems can transport cooling energy over long distances through piping with relatively low losses, making them practical for large building footprints, multi-story structures, and industrial process cooling over significant distances.
Chiller systems consist of four primary components: the compressor, which drives the refrigeration cycle; the condenser, which rejects heat to the air or condenser water loop; the evaporator or chiller barrel, where the refrigerant absorbs heat from the chilled water circuit; and the expansion device that controls refrigerant flow between the high and low pressure sides of the system. Supporting systems include chilled-water pumps, condenser-water pumps, and cooling towers for water-cooled systems; piping distribution; and control systems that manage the entire plant operation.
Types of Chillers Used in Commercial Buildings
Commercial chiller systems come in several configurations, each suited to different applications and building types.
Air-cooled chillers reject heat through a finned coil condenser using ambient outdoor air. They’re simpler to install and maintain than water-cooled systems because they don’t require a cooling tower or condenser water system. Air-cooled chillers are the most common type in smaller commercial buildings and are practical for facilities with limited space for cooling towers or water availability. Their efficiency decreases as outdoor temperatures rise, which is a relevant consideration for Indiana’s summer cooling loads.
Water-cooled chillers use a cooling tower or other water-based heat-rejection system, which allows them to operate more efficiently than air-cooled systems because condenser water temperatures can be lower than ambient air temperatures. Water-cooled systems are common in larger commercial buildings, hospitals, universities, and industrial facilities with significant cooling loads. They require more infrastructure but deliver better economic efficiency at scale.
Centrifugal chillers use a rotating impeller to compress refrigerant and are the most efficient technology available for large cooling loads, typically above 200 tons. They’re common in large commercial and institutional facilities and require skilled service technicians familiar with their specific operational characteristics.
Screw chillers use a helical rotor compressor and are well-suited to medium and large commercial applications. They offer good part-load efficiency and are more tolerant of variable operating conditions than centrifugal units.
Scroll chillers use scroll compressor technology and are common in smaller commercial applications. They’re reliable and relatively straightforward to service.
Common Chiller Problems and Warning Signs
Chiller failures rarely occur without warning. Recognizing developing problems early is the difference between a planned repair and an emergency shutdown.
Refrigerant leaks are among the most common chiller problems. Refrigerant loss reduces the system’s heat absorption capacity, which forces the chiller to run longer to meet the same cooling load. A low refrigerant charge also stresses the compressor, causing it to operate outside its design parameters. Signs include a gradual decline in cooling capacity, elevated compressor discharge temperatures, and refrigerant oil staining around fittings and connections.
Fouled heat exchangers reduce heat transfer efficiency on both the evaporator and condenser sides. Scale buildup on chiller tubes from poor water treatment, biological fouling in condenser water systems, and air-side fouling on air-cooled condensers all reduce the chiller’s effective capacity and increase energy consumption. Regular cleaning and water treatment management prevent these conditions from developing.
Compressor wear and failure are the most expensive chiller problems. Compressor issues typically develop over time through oil degradation, bearing wear, and refrigerant contamination. Vibration analysis, oil sampling, and electrical monitoring during preventive maintenance visits identify developing compressor problems before they become failures.
Control system issues produce symptoms that can be mistaken for refrigerant or mechanical problems. A chiller that’s short-cycling, failing to start, or displaying fault codes that don’t match actual system conditions may have control board, sensor, or actuator problems that a technician with chiller-specific diagnostic capability can distinguish from true mechanical failures.
Chilled-water and condenser-water pump failures interrupt the fluid circuits on which the chiller depends on. Pump failures are often accompanied by audible bearing noise, vibration, or seal leaks that precede complete failure.
Importance of Chiller Maintenance
Chillers are expensive to repair and even more expensive to replace. A maintenance program that extends the service life of a chiller by five years represents hundreds of thousands of dollars in deferred capital expenditure for a large commercial system. That math makes the cost of comprehensive annual maintenance look very different from what it does when viewed in isolation.
Beyond equipment life, consistent maintenance keeps the chiller operating at its design efficiency. A chiller operating at 90% of its design COP due to fouled heat exchangers and a degraded refrigerant charge is consuming 10% to 15% more electricity than it should. For a large commercial chiller running thousands of hours per year, that inefficiency represents a significant annual operating cost that maintenance would have eliminated.
Maintenance also provides the documentation trail that supports warranty claims, insurance requirements, and, eventually, the repair-versus-replace decision. Chillers with documented maintenance histories are easier to assess accurately than those without records.
Energy Efficiency Tips for Cooling Systems
Several operational strategies can maximize chiller efficiency in commercial facilities in Indiana.
Chilled water temperature reset adjusts the chilled water supply setpoint upward during periods of lower cooling demand. Each 1 °C increase in chilled water temperature improves chiller efficiency by approximately 1% to 1.5%. During mild shoulder-season days, resetting chilled water temperature to 46 or 48 degrees instead of 44 degrees meaningfully reduces compressor energy consumption.
Managing condenser water temperature is equally important for water-cooled systems. Allowing the cooling tower to produce the coldest condenser water conditions allowed, rather than controlling to a fixed setpoint, improves chiller efficiency during cooler Indiana spring and fall weather.
Chiller staging in plants with multiple units optimizes efficiency by running the minimum number of chillers needed at their most efficient load points. Running two chillers at 50% load is often more efficient than running one at 100% load, depending on the specific equipment’s part-load performance curves.
Free-cooling or waterside economizer operation during cold weather allows the cooling tower to provide cooling without running the chiller compressor, delivering dramatic efficiency gains during Indiana’s fall and spring seasons when outdoor temperatures permit.
Repair vs Replacement Considerations
The repair-versus-replace decision for commercial chillers involves multiple factors that extend beyond the immediate repair quote.
Age and remaining service life determine whether repair investment makes economic sense. Chillers typically have service lives of 20 to 25 years with proper maintenance. A 15-year-old chiller with a major compressor failure has reasonable remaining service life to justify significant repair investment. The same failure in a 22-year-old unit with documented reliability problems warrants a replacement analysis.
Refrigerant type affects long-term operating costs and replacement timing. Chillers using older, phased-out refrigerants face rising refrigerant costs and eventual replacement regardless of equipment condition.
Replacement efficiency gains should be quantified for older equipment. Replacing a 20-year-old chiller operating at a COP of 4.5 with a modern unit operating at 6.0 or higher delivers operating cost savings that can meaningfully offset replacement costs over the new unit’s life.
Choosing a Chiller Service Provider in Indiana
Chiller service requires specific training and experience that not every HVAC contractor possesses. Centrifugal and screw chillers, in particular, require technicians with manufacturer-specific training and the diagnostic equipment needed to work on these systems safely and effectively.
HMH Contractors provides commercial chiller services across Indiana, including installation, repair, and preventive maintenance for air-cooled and water-cooled chiller systems in commercial and industrial facilities. Their certified technicians work on all major chiller manufacturers and bring the equipment and expertise to handle everything from annual maintenance agreements to emergency chiller repairs and complete system replacements.
With 20-plus years of experience serving Indiana’s commercial and industrial markets and three locations across the state, HMH delivers the chiller service expertise large commercial facilities require, backed by a local presence that ensures responsive service.
Contact HMH Contractors today to discuss chiller service, maintenance agreements, or replacement planning for your facility in Indiana.
