Chiller Maintenance Checklist

A chiller rarely fails without warning signs showing up in the readings first — a rising condenser approach temperature, a refrigerant sight glass that’s started showing bubbles, a compressor amp draw that’s crept up a few points. Because a chiller’s compressor, condenser, evaporator, and refrigerant circuit all depend on each other, this checklist is organized by how often each area actually needs a look, from the readings logged every day to the full annual inspection and refrigerant leak-rate calculation most chillers are required to complete.

Industrial chiller unit in a mechanical room

Jump to a section Daily Weekly Monthly Quarterly Annual

Use the checkboxes below for routine checks, or print this page for the mechanical room log binder.

Daily

Log the chiller’s entering and leaving chilled-water temperatures, condenser water temperatures (water-cooled units), suction and discharge pressures, and compressor amperage
Review the control panel for active alarms or fault codes and record any found
Walk the machine room and listen for unusual noise or vibration, and look for visible leaks at piping joints and connections
Check the refrigerant sight glass, where present, for bubbles — a possible sign of low refrigerant charge

Weekly

Review the week’s logged readings for drift from normal — a rising approach temperature, a shrinking delta-T, or a creeping amp draw
Where an oil sight glass or gauge is accessible, confirm the compressor’s oil sits at the correct level and isn’t discolored or contaminated
Inspect chilled-water and condenser-water pump operation, coupling, and seals for leaks or unusual noise
Check water strainer screens for debris and clean or replace as needed
Test condenser water (or a closed-loop glycol mix) for pH, conductivity, and signs of biological growth, or confirm the water-treatment provider’s latest results
Confirm the chiller’s auto-start/auto-stop sequence and any scheduling controls are functioning as expected

Monthly

Inspect air-cooled condenser coils and fins for fouling, debris, or bent fins, and clean as needed
Confirm each condenser fan motor spins in the correct direction, runs smoothly, and draws amperage within its nameplate rating
Inspect electrical connections and terminals at the control panel and motor starter for tightness, pitting, or discoloration
Leak-check refrigerant piping joints and connections, especially any flagged on a previous inspection
Verify flow switches and low-temperature cutout controls trip correctly
Record subcooling and superheat values and compare against the manufacturer’s normal range
On a glycol loop, verify the mixture’s freeze point and glycol percentage are still within the system’s design range

Quarterly

Send an oil sample out for lab analysis on larger compressors, per manufacturer guidance
Verify temperature sensors and pressure transducers are still reading accurately, and recalibrate any that have drifted
Review water-treatment program results with the service provider and adjust chemical feed if needed
Where evaporator tubes are accessible, look for scale buildup or corrosion on the tube surfaces
Check variable-frequency-drive parameters and fault history if the chiller is VFD-equipped
Verify both the high- and low-pressure safety cutouts trip and reset as designed
Look over the refrigeration system’s relief valves for rust or pitting, and check whether any show signs of having released in the past

Annual

Clean condenser tubes (water-cooled) or thoroughly clean condenser coils (air-cooled)
Inspect and clean evaporator tubes, and schedule eddy-current tube testing on larger chillers per manufacturer guidance
Change compressor oil and filters per the manufacturer’s specified interval
Schedule a full inspection by a qualified chiller technician, covering mechanical and electrical components
Test the machine room’s emergency ventilation system and refrigerant detector/alarm
Calculate the system’s annualized refrigerant leak rate from the year’s service records and compare it against the applicable EPA thresholdSystems with a full charge of 50 lbs or more of covered refrigerant are generally subject to a leak-repair requirement if the annualized rate exceeds the threshold set for that appliance type.^[1]
Review and update the written lockout/tagout energy-control procedure for the chiller
Archive the year’s logs, service records, and refrigerant documentationA minimum 3-year retention is a common recordkeeping practice for refrigerant service records — confirm the applicable requirement for the specific system and jurisdiction.

Note: This checklist is a general maintenance reference and recommended starting point for chiller maintenance programs — it is not a substitute for the manufacturer’s service manual or applicable regulatory requirements. Actual tasks and frequencies should reflect the specific chiller type, size, and application. See the full disclaimer below before using or adapting these recommendations.

What Is a Chiller Maintenance Checklist?

A chiller maintenance checklist is a documented set of inspection, logging, and service tasks covering the systems that keep a chiller running efficiently and safely — the compressor, condenser, evaporator, refrigerant circuit, controls, and (for water-cooled units) the paired water-treatment program.

Chillers depend on consistent, trended readings more than almost any other piece of mechanical equipment in a facility — a single reading rarely tells you much, but the same reading logged daily and watched for drift is often the earliest warning a problem is developing. That’s why this checklist, like the eWorkOrders Chiller Maintenance: Common Issues, Solutions & Tips guide it’s paired with, is organized by frequency rather than by component alone.

The specific tasks and intervals differ by chiller type, size, and application. Follow the manufacturer’s service manual for the specific unit, and adjust frequencies for load, water quality, and run hours.

Key Systems to Inspect on a Chiller

Compressor: Oil level and condition, vibration, amperage, and capacity controls.

Condenser & Heat Rejection: Coils or tubes, fan motors, and approach temperature.

Evaporator: Tube condition, approach temperature, and freeze-protection controls.

Refrigerant Circuit: Charge level, sight glass, subcooling/superheat, and leak points.

Controls & Electrical: Sensors, starters, connections, and VFD parameters.

Water Treatment (Water-Cooled): Chemical feed, pH, conductivity, and glycol concentration.

Safety Considerations for Chiller Maintenance

Chiller maintenance combines pressurized refrigerant, high-voltage electrical equipment, and in many facilities, water-treatment chemicals — a few points apply across most systems:

Refrigerant work requires certification. In the U.S., technicians who service a chiller’s refrigerant circuit must be certified under EPA Section 608, and systems holding a large enough refrigerant charge carry leak-repair and recordkeeping obligations of their own.^[1]^[2]

Lock out and tag out before service. Isolate electrical energy and relieve pressure in the relevant circuit before opening a panel, servicing the compressor, or working near rotating components.

Machine rooms have their own code requirements. Refrigerant detectors, mechanical ventilation, and alarms in the chiller’s machine room should be tested and kept in working order as required by applicable mechanical and fire codes.

Water-treatment chemicals carry their own hazards. Follow the safety data sheet and the water-treatment provider’s handling procedures for any chemicals used in the condenser or chilled-water loop.

Personal Protective Equipment (PPE)

The right PPE depends on the specific task and the facility’s own safety program, but most chiller maintenance work calls for some combination of the following:

Eye & Face Protection

Safety glasses or a face shield when working near pressurized refrigerant lines or handling water-treatment chemicals.

Hand Protection

Chemical-resistant gloves for water-treatment chemicals, and insulated or cut-resistant gloves as the electrical or mechanical task requires.

Hearing Protection

Hearing protection in mechanical rooms where compressor and pump noise levels warrant it.

Electrical PPE

Appropriately rated electrical PPE when work requires opening an energized panel, per the facility’s electrical safety program.

Common Chiller Maintenance Mistakes

Treating a single reading as the diagnosis

One slightly-high pressure or amperage reading rarely means much by itself — the same reading tracked over weeks and compared to the chiller’s own history is what actually reveals a developing problem.

Calculating the refrigerant leak rate only at reporting time

Waiting until an annual report is due to add up the year’s refrigerant additions turns a straightforward calculation into guesswork, and can leave a real compliance obligation undetected for months.

Maintaining the chiller without maintaining the cooling tower it depends on

A water-cooled chiller’s performance is tied directly to its cooling tower’s condition — see the Cooling Tower Maintenance Checklist for the companion system.

Frequently Asked Questions

What is a chiller maintenance checklist?

A chiller maintenance checklist is a documented set of inspection, logging, and service tasks covering a chiller’s compressor, condenser, evaporator, refrigerant circuit, controls, and — for water-cooled units — its water-treatment program, organized so each area gets checked at an appropriate frequency.

How often should a chiller be serviced?

Most chillers need daily reading logs, weekly trend reviews and basic checks, monthly condenser and electrical inspections, quarterly oil analysis and sensor calibration, and an annual full-service inspection including tube cleaning and a refrigerant leak-rate calculation. Follow the manufacturer’s recommendations for the specific model.

What is EPA Section 608 and does it apply to chiller maintenance?

EPA Section 608 is the federal refrigerant management program under the Clean Air Act. It requires technicians who service a chiller’s refrigerant circuit to be certified, and it sets leak-repair and recordkeeping requirements for systems holding a large enough refrigerant charge — generally a 10% annualized leak-rate repair trigger for comfort-cooling systems like most building chillers, for appliances with a full charge of 50 lbs or more of covered refrigerant. Confirm the current threshold and requirements for the specific system.

What is condenser approach temperature and why does it matter?

Condenser approach is the difference between the refrigerant’s condensing temperature and the leaving condenser water (or outdoor air) temperature. A rising approach over time usually points to fouled condenser tubes or coils, or non-condensable gases in the system, and is one of the earliest signs of lost efficiency.

What’s the difference between air-cooled and water-cooled chiller maintenance?

Air-cooled chillers reject heat through outdoor fans and condenser coils, so their maintenance focuses on coil cleanliness and fan operation. Water-cooled chillers reject heat to condenser water cooled by a cooling tower, so their maintenance adds condenser tube cleaning and an ongoing water-treatment program, in addition to maintaining the paired cooling tower itself.

Why is my chiller losing cooling capacity?

Common causes include a low refrigerant charge or a leak, fouled condenser or evaporator tubes, dirty air-cooled condenser coils, a failing compressor, or a heat load that’s grown beyond the chiller’s capacity. Comparing current readings against the chiller’s own logged history usually narrows down the cause.

How does a CMMS help with chiller maintenance?

A CMMS helps by scheduling recurring PM work and logging tasks for the chiller, assigning that work to a technician, and keeping a connected record of readings, inspection findings, and repair history tied to the chiller as an asset.

How eWorkOrders CMMS Supports Chiller Maintenance

PM Scheduling

Recurring PM schedules can be set for chiller logging, inspections, and service tasks by calendar date.

Work Assignment

PMs and repair work orders are assigned to specific technicians or work groups.

Asset History

Each chiller has a connected record of logged readings, completed PMs, oil-analysis results, and repair history.

Condition Monitoring

eWorkOrders integrates with condition-monitoring partners like AssetWatch, which can auto-generate a work order when a monitored value — such as compressor vibration — crosses a set threshold, catching a developing fault before it shows up on the next scheduled check.

By Janet Jaquis, Marketing Director | CMMS Software Specialist · Updated October 2026

Additional Resources

Part of the eWorkOrders Learning Center
The Ultimate Library of Maintenance Checklists
Chiller Maintenance: Common Issues, Solutions & Tips — the full guide to how chillers work, common problems, and troubleshooting
Cooling Tower Maintenance Checklist — the companion system for water-cooled chillers
Commercial HVAC Maintenance Checklist
Boiler Maintenance Checklist

References

U.S. Environmental Protection Agency. Section 608 — Stationary Refrigeration and Air Conditioning (technician certification and refrigerant management requirements).
U.S. Environmental Protection Agency, 40 CFR § 82.157, via Cornell Law School Legal Information Institute. Leak repair requirements for appliances with a full charge of 50 or more pounds of covered refrigerant.

A Rising Approach Temperature Rarely Means Much on Its Own

A few extra degrees on the condenser approach, a sight glass showing the occasional bubble — neither one is a crisis by itself, but tracked against a chiller’s own history, it’s often the first sign the tubes need cleaning or the charge has shifted. eWorkOrders lets your team schedule recurring chiller PMs, assign the related work orders to a technician, and record meter readings and inspection results for review with the chiller’s maintenance records.

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Important Disclaimer: This chiller maintenance checklist is provided by eWorkOrders as a general reference and recommended starting point for chiller maintenance programs. The tasks, inspection intervals, and suggested maintenance considerations are recommendations only. They are not intended to establish a universal maintenance schedule or to state that every task applies to every chiller.

Chiller maintenance requirements vary according to chiller type (air-cooled, water-cooled, absorption, evaporative-cooled), compressor type, size, age, refrigerant type and charge, water quality, operating environment, manufacturer specifications, jurisdiction, and applicable laws, codes, and standards (including EPA Section 608 and other regulations where applicable).

Before using this checklist, facility owners, maintenance managers, and other responsible personnel should review and adapt it for the specific chiller and conditions in their operation. Appropriate tasks, inspection intervals, and acceptance criteria should be established using the manufacturer’s service documentation, applicable regulatory requirements, and the judgment of qualified maintenance and refrigeration personnel.

This checklist does not replace manufacturer documentation, applicable federal, state, or local laws and regulations (including EPA Section 608 requirements where they apply), requirements of the authority having jurisdiction, the facility’s own safety program, or the judgment of qualified personnel.

Chiller maintenance work can expose workers to serious hazards, including electrical shock, pressurized-refrigerant release, chemical exposure from water-treatment products, and injury from rotating equipment. Such work should only be performed by personnel who are appropriately trained, certified where required (including EPA Section 608 certification for refrigerant work), and equipped for the work, following applicable lockout/tagout and other safety procedures.

eWorkOrders makes no representation that this checklist is complete or appropriate for any particular chiller, facility, jurisdiction, or operating environment. Responsibility for determining the appropriate maintenance activities, inspection frequencies, and compliance obligations remains with the facility and the qualified professionals responsible for it.