Commercial HVAC Preventative Maintenance Checklist

Preventative maintenance is the cornerstone of reliable commercial HVAC operations. This comprehensive checklist covers the essential tasks that should be performed quarterly to ensure your system operates efficiently and avoids unexpected failures.

Why Preventative Maintenance Matters

In Oklahoma’s extreme climate—with summer temperatures exceeding 100°F and winter lows below freezing—HVAC systems work harder than in most regions. Without regular maintenance, you’re not just risking comfort; you’re risking:

Risk Category	Without PM	With PM Program
Unplanned downtime	3-5 events/year	Rare (under 1/year)
Energy cost increase	20-30% higher	Optimized baseline
Equipment lifespan	5-10 years shorter	Full design life
Air quality compliance	At risk	Maintained
Emergency repair costs	$15,000-50,000/year	Under $5,000/year

Photo credit: smartcaresolutions.com

Quarterly Maintenance Tasks

Air Handling Units (RTUs, MAUs, AHUs)

Filters

Task	Check	Standard
Visual inspection	Loading level, damage	Replace if over 50% loaded
Filter replacement	Per manufacturer spec	Typically 1-3 months
Rack sealing	No bypass gaps	Full contact all edges
Size documentation	Correct for unit	Match nameplate
MERV rating	Appropriate for application	Per design requirements

Belts & Drives

Component	Inspection	Action If Failed
Belt tension	Per manufacturer spec	Adjust or replace
Belt condition	Cracks, glazing, wear	Replace
Pulley alignment	Parallel, no wobble	Realign
Pulley wear	Groove condition	Replace if worn
Bearings	Noise, temperature, vibration	Lubricate or replace
Motor amps	Compare to nameplate	Investigate if high

Coils

Check	Purpose	Action
Visual inspection	Fouling, damage	Clean if restricted
Fin condition	Bent, crushed	Comb fins
Condensate drain	Clear, proper flow	Clear blockages
Drain trap	Properly primed	Prime if dry
Condensate pump	Operational	Test float switch

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Controls

Control Component	Test	Pass Criteria
Thermostat	Calibration check	Within 2°F of setpoint
Economizer damper	Full stroke test	Opens/closes fully
Actuator response	Timing test	Per specification
Wiring	Visual inspection	No damage, tight connections
Sensors	Calibration verification	Within tolerance

Chillers

Daily Checks (Automated or Operator)

Parameter	Normal Indication	Alarm Trigger
Operating logs	No anomalies	Error codes present
Approach temperatures	Within design range	Greater than 5°F over design
Refrigerant levels	Stable	Dropping trend
Alarm history	Clear	New or repeated alarms
Oil level/pressure	Normal range	Low level or pressure

Quarterly Service

Task	Purpose	Documentation
Oil analysis (centrifugal)	Detect wear, contamination	Lab report
Refrigerant leak check	Prevent charge loss	Inspection record
Starter contacts	Prevent electrical failure	Condition noted
Safety controls	Verify protection	Test results
Condenser coil cleaning	Maintain heat rejection	Before/after photos
Water treatment review	Protect tubes	Chemistry logs

Boilers

Safety First

Safety Device	Test Method	Frequency
Low-water cutoff	Blowdown test	Weekly
Safety valve	Visual inspection (do not test manually)	Annual (by inspector)
Flame safeguard	Functional test	Annual
Burner operation	Visual inspection	Weekly
High limit	Verification	Monthly

Performance

Task	Purpose	Measurement
Combustion analysis	Verify efficiency	O2, CO, stack temp
Steam pressure controls	Proper modulation	Setpoint accuracy
Refractory inspection	Prevent heat loss	Visual condition
Gasket condition	Prevent leaks	Visual inspection
Feedwater pump	Reliable operation	Amps, flow, noise

Oklahoma-Specific Considerations

Seasonal Focus Areas

Season	Primary Focus	Key Risks	Recommended Actions
Summer (May-Sept)	Chillers, cooling towers, condensers	Algae growth, high head pressure	Weekly water treatment, condenser cleaning
Winter (Nov-March)	Boilers, heat exchangers, freeze protection	Freeze damage, combustion issues	Glycol verification, safety testing
Spring/Fall	Changeover systems	Mode transition failures	Test both modes before demand

Summer (May - September)

• Increased Focus: Chillers, cooling towers, condensers
• Risk: Algae growth in cooling towers from high humidity
• Action: Weekly water treatment monitoring

Winter (November - March)

• Increased Focus: Boilers, heat exchangers, freeze protection
• Risk: Freeze damage to outdoor equipment
• Action: Verify glycol concentration in exposed piping

Spring/Fall Transition

• Changeover Period: Switch between heating and cooling modes
• Action: Test both modes before seasonal demand

When to Call for Professional Service

While some tasks can be handled in-house, certain maintenance requires factory-trained technicians:

Service Type	Why Professional	Certification/Equipment
Refrigerant handling	Legal requirement	EPA 608 certification
Combustion tuning	Safety and efficiency	Gas analysis equipment
Electrical troubleshooting	High-voltage hazards	Licensed electrician
Pressure vessel inspection	Code compliance	ASME R-Stamp
Controls programming	System integration	Manufacturer training
VFD service	Specialized knowledge	Factory certification

Cost vs. Downtime Analysis

Scenario	Annual Cost	Risk Level	Typical Outcome
Comprehensive PM Program	$8,000 - $15,000	Low	Predictable, minimal surprises
Reactive Maintenance Only	$12,000 - $30,000	High	Frequent emergencies
Summer Chiller Failure	$50,000+	Critical	Emergency + lost revenue
Winter Boiler Failure	$25,000+	Critical	Building closure risk

PM Program ROI by Equipment Type

Equipment	PM Cost/Year	Avoided Repairs	Energy Savings	Total ROI
Chiller (200-ton)	$3,500	$8,000 avg	$4,500	3.6x
Boiler (100 HP)	$2,000	$5,000 avg	$3,000	4.0x
RTU (25-ton)	$800	$2,500 avg	$1,200	4.6x
Cooling Tower	$1,500	$4,000 avg	$2,000	4.0x

Maintenance Documentation Best Practices

Document Type	Contents	Retention
Service reports	Tasks completed, findings, recommendations	5 years minimum
Equipment logs	Run hours, alarms, performance data	Life of equipment
Repair history	Parts replaced, costs, technician notes	Life of equipment
Inspection photos	Before/after, deficiencies found	3 years minimum
Compliance records	Certifications, test results	Per code requirements

Get Started with a PM Agreement

Total Mechanical Services offers customized preventative maintenance agreements for commercial facilities across Oklahoma. Our programs include:

Program Feature	Standard	Premium	Enterprise
Quarterly scheduled service	Yes	Yes	Yes
Priority emergency response	24-hour	4-hour	2-hour
Detailed inspection reports	Yes	Yes	Yes
Equipment lifecycle planning	Annual	Quarterly	Continuous
Parts discount	10%	15%	20%
Energy analysis	Annual	Semi-annual	Quarterly

Request a Proposal or call our commercial division at (405) 223-9900.

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This checklist is based on industry best practices and Oklahoma climate conditions. Your specific equipment may require additional tasks per manufacturer recommendations.