The Commercial HVAC Preventive Maintenance Checklist, by Equipment Type

Monthly to quarterly: inspect and change air filters, check belt tension and alignment, clear and treat the condensate drain, and inspect the economizer dampers and changeover setpoint. Seasonally (before cooling and before heating): clean condenser and evaporator coils, measure compressor amperage against the nameplate, check refrigerant charge and inspect for leaks, test safety controls, verify the gas-heat section — ignition, flame sensor, and a heat-exchanger inspection — and confirm thermostat/BAS sequencing. Coils are the priority: dirt acts like insulation and forces the compressor to overwork.

Monthly/quarterly: check filters where applicable, log operating temperatures and pressures, verify flow, and review safety and control setpoints. Annually (typically before the cooling season): clean or eddy-current test the tubes, perform compressor oil and refrigerant-oil analysis, inspect and test starters/VFDs and safeties, calibrate sensors, and complete a refrigerant leak check with EPA-compliant handling. Trending the chiller's approach temperatures and kW/ton over time is what catches fouling and efficiency loss before it becomes a breakdown.

Weekly: test water chemistry — pH (commonly held around 7–8), conductivity, and biocide levels — and inspect for visible biofilm or scale. Monthly: inspect the fill, drift eliminators, fan, gearbox or belt, float and make-up valve, and basin; clean as needed. Seasonally: a thorough basin cleaning, mechanical inspection, and verification of the water-treatment program. Cooling-tower water treatment is also a Legionella risk-management obligation, which is why documented treatment logs matter, not just clean water.

Pre-season (before heating) and monthly during the heating season: inspect and test the burner and ignition, perform a combustion analysis and tune for efficiency and safe CO levels, test safety and limit controls and the low-water cutoff, check and treat boiler water, inspect for leaks, and verify the controls and aquastat/pressuretrol settings. Combustion tuning and safety-control testing are the non-negotiables — they protect both efficiency and life safety.

Quarterly to annually: verify sensors against reference readings and recalibrate drift, review and confirm schedules and setpoints, check that control sequences (economizer changeover, staging, resets) are operating as designed, audit alarms and overrides, and confirm trends are logging. A drifted sensor or a forgotten manual override silently undoes the work every other PM task is trying to accomplish, so controls verification multiplies the value of all the rest.

Monthly/quarterly: change filters, check belts and bearings, inspect dampers and actuators, and confirm condensate handling. Seasonally: clean coils, inspect and lubricate pumps and motors, check pump seals and verify flow, inspect VAV/terminal boxes, and confirm airflow and balancing where comfort complaints suggest drift. Clean filters and coils plus healthy belts and bearings are what keep airflow — and the efficiency that depends on it — where the system was designed to deliver.

• •Filter and belt service monthly/quarterly
• •Coil cleaning and refrigerant checks seasonally
• •Economizer damper and setpoint verification
• •Gas-heat ignition and heat-exchanger safety inspection

• •Chiller tube cleaning, oil analysis, and leak checks
• •Boiler combustion tuning and safety-control testing
• •Cooling-tower water treatment and basin cleaning
• •Performance trending to catch efficiency loss

• •Filter, belt, bearing, and damper service
• •Pump and motor inspection and lubrication
• •BAS sensor calibration and setpoint review
• •Airflow and balancing checks where comfort drifts

One contractor for every system

RTUs, chillers, boilers, cooling towers, air handlers, and controls under one maintenance program — instead of juggling separate vendors for each piece of equipment.

Measurement, not just visual checks

We log amperages, pressures, water chemistry, and combustion readings against benchmarks, so we catch the efficiency loss and impending failures a walk-around misses.

Commercial-only focus

We maintain commercial and multifamily equipment across the NYC metro every day, so our checklists reflect how this equipment actually wears and fails in the field.

Documentation built for owners

Clear records, water-treatment logs, and trended performance give you the paper trail that supports warranties, compliance, and capital planning.

Maintenance Assessment

The starting point: an equipment inventory and a recommended preventive-maintenance scope and cadence for your building.

Scheduled PM Program

Recurring preventive maintenance across your equipment on the right cadence.

Portfolio Program

One coordinated maintenance program across multiple buildings or sites.

Own a Commercial Property?

Business+ plans start at $499/year — includes 2 rtu tune-ups, 10% off all services, and priority scheduling.

How often should commercial HVAC be serviced?

A good program uses several cadences rather than one annual visit. Simple tasks — filter checks, visual inspections, and cooling-tower water testing — happen monthly or more often. Mechanical checks like belts, amperage readings, and control verification are typically quarterly. The deeper work — coil cleaning, chiller tube cleaning, boiler combustion tuning, full safety testing — is done seasonally, timed before the cooling and heating peaks. Equipment serving critical loads or revenue spaces warrants tighter intervals.

What's actually included in commercial HVAC preventive maintenance?

It varies by equipment, which is the whole point of an equipment-by-equipment checklist. For an RTU it means filters, belts, coil cleaning, refrigerant and amperage checks, condensate and economizer service, and gas-heat safety inspection. For a chiller it means tube cleaning, oil analysis, sensor calibration, and leak checks. For a boiler it means combustion tuning and safety-control testing. For a cooling tower it means water treatment, mechanical inspection, and basin cleaning. And across all of it, BAS sensor calibration and setpoint verification tie the system together.

Does preventive maintenance really save money versus just fixing things when they break?

Yes, on two fronts. First, energy: tasks like coil cleaning and correct refrigerant charge keep equipment near its design efficiency, while a neglected unit burns more energy every month — dirty coils alone cost several percent of efficiency per year. Second, failure cost: emergency repairs carry premium labor, expedited parts, and tenant-disruption costs that planned maintenance avoids, and PM extends equipment life so major replacements come later. The recurring cost of maintenance is consistently a fraction of the emergency-and-replacement spending it prevents.

Why does cooling-tower water treatment get its own attention?

Because untreated cooling-tower water grows scale, corrosion, and biofilm that wreck efficiency and equipment — and because it's a Legionella risk-management issue with documentation obligations. A proper program tests chemistry frequently (pH commonly held around 7–8, plus conductivity and biocide levels), maintains treatment, and logs it. The logging isn't bureaucratic box-checking; it's the record that demonstrates the water is being managed for both performance and public-health reasons.

What maintenance is most important for a commercial boiler?

Combustion tuning and safety-control testing. A combustion analysis confirms the boiler is burning efficiently and within safe carbon-monoxide limits, and tuning recovers efficiency that drifts over a season. Testing the safety and limit controls and the low-water cutoff protects against dangerous failure modes. Add water treatment, leak inspection, and control verification, and time the heavy work for before the heating season so the boiler is ready when you need it rather than failing on the first cold night.

Can one contractor maintain all of our different HVAC equipment?

That's the ideal arrangement. Buildings often run a mix — rooftop units, a chiller, a boiler, a cooling tower, air handlers, and a building-automation system — and splitting those across vendors fragments accountability and documentation. A single commercial contractor maintaining everything gives you one cadence, one record, one point of contact, and a whole-building view that feeds capital planning. Com+ Mechanical runs that kind of consolidated program across the NYC metro.

When should cooling-side and heating-side maintenance be scheduled?

Before the peaks. Cooling-side work — coil cleaning, chiller service, cooling-tower preparation, refrigerant checks — is best completed in spring, before summer load arrives. Heating-side work — boiler combustion tuning, safety testing, burner service — belongs in fall, before the first hard cold. Scheduling deep maintenance ahead of the season means problems are found on a planned visit instead of as an emergency when the equipment is under full load and a failure hits hardest.

Does maintenance documentation matter beyond just record-keeping?

Considerably. Documented maintenance supports equipment warranties (many require proof of service), demonstrates compliance for items like cooling-tower water treatment and combustion safety, and creates the performance history that makes repair-vs-replace and capital decisions defensible. Trended readings also surface slow efficiency loss and equipment drifting toward end-of-life, so the same documentation that proves you maintained the equipment also tells you when it's time to plan a replacement.