By Tamika Brooks · Updated October 22, 2026 · 7 min read
Short answer
A preventive maintenance plan lists each asset, the tasks it needs, how often, who does them and how results are recorded. For chillers, rooftop units and refrigeration, tasks cluster by frequency: frequent visual and log checks, seasonal inspections, and annual deep checks. Good records, trend review and manufacturer instructions turn a checklist into a program that lowers failures and cost.
A preventive maintenance (PM) plan is a written schedule of tasks that keep building equipment running before it fails. It lists each asset, what must be done, how often, who does it and where results are recorded. For commercial HVAC and refrigeration, a good plan covers chillers, rooftop units (RTUs) and refrigeration equipment, follows the manufacturer’s instructions and records readings so trends can be seen. The main benefit is fewer surprise failures and longer equipment life.
What does a preventive maintenance plan include?
A useful plan has six parts:
- Asset list: every unit with model, serial number, location, age, refrigerant type and charge.
- Task list: tasks per asset, taken from the manufacturer’s manual and codes.
- Frequency: how often each task is done, by calendar or run hours.
- Responsibility: who performs and who signs off, in-house or contractor.
- Records: forms or software that capture readings, findings and parts.
- Review: a regular look at trends, failures and costs to adjust the plan.
Preventive work differs from predictive work (using data such as vibration or oil analysis to time repairs) and corrective work (fixing after failure). A mature program uses all three, with PM as the foundation.
What should a chiller PM plan cover?
Chillers carry high value and high consequence, so their plans are the most detailed. The tables below are general examples. Always confirm with the manufacturer’s manual.
| Frequency | Typical tasks |
|---|---|
| Daily or each shift | Log temperatures, pressures, amps, oil level and alarms |
| Monthly | Visual walk-around, oil check, strainers, pump and motor condition, controls check, tower and water treatment checks |
| Annual | Tube inspection and cleaning, oil analysis and filters, leak check, electrical and starter checks, safety device tests, sensor calibration, vibration |
| Multi-year | Tube eddy-current testing, major overhauls per run hours, controls and starter upgrades |
A fuller walk-through is in the chiller maintenance checklist. Oil results are covered in what oil analysis tells you, and water-side work in cooling tower basics.
What should a rooftop unit PM plan cover?
RTUs are many and exposed to weather, so a plan works best when it is simple and consistent across the fleet.
| Frequency | Typical tasks |
|---|---|
| Monthly or quarterly | Replace or check filters, look for belt wear, check condensate drains, confirm thermostat or BAS operation |
| Seasonal (spring and fall) | Clean condenser and evaporator coils, check economizer operation, inspect fan and motor, tighten electrical connections, check heat section |
| Annual | Test safeties, measure airflow and temperature split, check refrigerant leaks, inspect cabinet, curb and roof penetrations |
Filters and coils have the largest effect on energy use and breakdowns. Many RTUs are changing to A2L refrigerants, which affects future work and training; see RTU basics and the A2L transition.
What should a refrigeration PM plan cover?
Walk-in boxes, display cases and larger systems need checks that reflect food safety and constant run time.
| Frequency | Typical tasks |
|---|---|
| Weekly or monthly | Check box temperatures, door seals, evaporator ice and drain pans, and review alarm logs |
| Quarterly | Clean condensers, check fan motors, inspect defrost operation, check sight glass and oil where fitted |
| Annual | Leak checks and records, electrical checks, controller and sensor calibration, safety tests, insulation and panel inspection |
For common warning signs, see walk-in cooler not cooling: common causes.
How should PM records be kept?
Records prove that the program exists and reveal trends. At minimum:
- Date, asset ID, task done and name of the person who did it.
- Readings such as temperatures, pressures, amps and approach temperatures, recorded under similar load.
- Findings and corrective actions, with dates for follow-up.
- Parts used and refrigerant added or recovered, since federal rules require records for some leak and refrigerant activities. See EPA 608 leak repair rules.
- Warranty and code related documents, such as inspection certificates.
A computerized maintenance management system (CMMS) makes scheduling and history easier, but a spreadsheet and consistent forms work for a small portfolio. What matters is that data is entered each visit and reviewed.
How do you build a PM plan from scratch?
- Inventory the equipment and rank it by criticality: what stops if it fails.
- Collect the manufacturer’s maintenance instructions and warranty conditions.
- Draft tasks and intervals, then separate what in-house staff can do from what needs specialized or certified people. Refrigerant work needs EPA certification, and electrical and pressure vessel work has its own safety rules.
- Decide on the record format and who reviews it.
- Start with the critical assets, expand after a quarter, and adjust intervals using failure and trend data.
- Review annually and after any major failure.
How do you know if the plan is working?
Look at fewer unplanned shutdowns, stable energy use per unit of load, more repairs found during inspections rather than during breakdowns, and falling emergency repair spending. If the same failure keeps repeating, change the task or interval rather than just repeating the repair.
Frequently asked questions
How often should commercial HVAC be serviced?
There is no single answer. Manufacturers give minimums, and operating hours, environment and criticality push the schedule up or down. Many owners inspect RTUs at least twice a year and chillers more often.
Is a PM plan required by law?
Not as a general rule, but some codes, insurers, warranties and regulated activities, such as refrigerant leak tracking or healthcare and food facilities, require inspections and records. Check current rules and your contracts.
Can in-house staff do all the PM work?
They can handle many routine checks, such as filters, logs and visual inspections. Work involving refrigerant, controls programming or high voltage should be done by suitably trained and certified people.
SpecServis engineers in Ukraine have experience with maintenance practices for chillers, compressors and refrigeration plants. We are planning to enter the Central Texas market and are looking for technicians, partners and a company to buy. See our open positions or partnership options.
