PRE-SEASON HVAC COMMISSIONING CHECKLIST

Seasonal transitions place the greatest stress on commercial HVAC systems. Equipment that sat idle in heating or cooling mode for months is asked to restart, modulate, and hold setpoint under full load almost immediately — and small deferred-maintenance issues that were invisible in shoulder season become comfort complaints, energy waste, or equipment failures within the first few weeks of the new season.

This checklist is built around the same audit discipline Energy Sense Building Solutions applies to ASHRAE Level I-III commercial energy audits: verify the control sequence first, confirm airflow and heat transfer second, and validate refrigerant and combustion safety last. Used consistently each spring and fall, it converts seasonal startup from a reactive scramble into a documented, defensible maintenance record.

Confirm the building automation system is reading real values, executing the intended sequence of operations, and free of overrides left from the prior season before any mechanical testing begins.

• 1.Confirm BAS front-end communication with all rooftop units, AHUs, and zone controllers — no offline or unacknowledged alarm points.PFN/A
• 2.Verify outdoor air temperature and humidity sensors against a calibrated handheld reference (+/- 1 degree F / +/- 3% RH tolerance).PFN/A
• 3.Confirm space temperature sensors in representative zones match handheld readings; recalibrate or replace drifted sensors.PFN/A
• 4.Review and clear all manual overrides, forced points, and operator bypasses left active from the previous season.PFN/A
• 5.Verify occupied/unoccupied scheduling reflects current building hours and any holiday/closure calendar updates.PFN/A
• 6.Confirm economizer changeover setpoint and lockout logic matches design intent for the upcoming season.PFN/A
• 7.Test demand-controlled ventilation (CO2 reset) sequence where installed; verify minimum OA damper position fails safely open.PFN/A
• 8.Verify supply air temperature reset sequence and confirm reset schedule aligns with current setpoints.PFN/A
• 9.Confirm staging and lockout sequence for multi-stage equipment (compressors, heat sections) operates in correct order.PFN/A
• 10.Test and document time-delay/anti-short-cycle protection on each compressor and confirm field timer settings match design.PFN/A

Airflow deficiencies are the most common root cause of comfort complaints and reduced equipment efficiency. Verify both the delivery path and the measurement instrumentation before the season's first full-load day.

• 11.Inspect and replace all air filters; record static pressure drop across filter bank (clean vs. dirty reading).PFN/A
• 12.Measure total supply airflow at each AHU/RTU and compare to design CFM; flag any unit reading below 90% of design.PFN/A
• 13.Inspect supply, return, and exhaust fan belts for wear, glazing, or misalignment; replace and re-tension as needed.PFN/A
• 14.Verify fan motor amperage draw against nameplate; confirm VFD-driven fans are not exceeding rated current at full speed.PFN/A
• 15.Inspect dampers (OA, RA, exhaust, mixed-air) for full stroke travel and confirm actuators are not slipping on the shaft.PFN/A
• 16.Check ductwork accessible in mechanical rooms and above ceilings for disconnected sections, crushed runs, or insulation failure.PFN/A
• 17.Verify minimum outdoor air ventilation rate at each unit meets current ventilation standard for the space served.PFN/A
• 18.Inspect and clean supply diffusers, return grilles, and VAV box inlets in a representative sample of zones.PFN/A
• 19.Test VAV box minimum/maximum airflow setpoints against design and confirm box dampers respond to BAS commands.PFN/A
• 20.Confirm exhaust fan interlocks (kitchen hood, restroom, lab) operate correctly and make-up air responds as designed.PFN/A

Coil fouling, water-side fouling, and hydronic balancing drift are gradual — they rarely trigger an alarm, but they steadily erode capacity and efficiency until a peak-load day exposes the shortfall.

• 21.Inspect evaporator and condenser coil fins for dirt loading, bent fins, or biological growth; clean with appropriate coil cleaner.PFN/A
• 22.Check condensate drain pans and lines for standing water, biological growth, or blockage; verify trap is properly primed.PFN/A
• 23.Inspect condensate overflow switches and confirm they trip equipment offline when tested.PFN/A
• 24.Verify chilled water and hot water supply/return temperature differential matches design delta-T at representative coils.PFN/A
• 25.Inspect hydronic strainers (pump suction, coil inlet) for debris loading; clean and record pressure drop before/after.PFN/A
• 26.Test and lubricate pump bearings; verify pump motor amperage against nameplate and check for cavitation noise.PFN/A
• 27.Inspect glycol concentration (where used) with a refractometer and confirm freeze-protection level meets local design conditions.PFN/A
• 28.Verify air has been bled from hydronic loops at high points; check expansion tank pressure against system static fill pressure.PFN/A
• 29.Inspect cooling tower fill, basin, and float valve (cooling-season units) for scale, debris, or mechanical wear.PFN/A
• 30.Confirm water treatment program (chemical feed, blowdown control) is active and most recent water analysis is within target range.PFN/A

A correctly charged system that loses 10% capacity to a fouled condenser will read like a refrigerant problem. Confirm airflow and heat rejection first, then validate the refrigerant circuit itself.

• 31.Inspect condenser coil and fan for debris, bent fins, or obstructed airflow; clean and verify free fan rotation.PFN/A
• 32.Verify refrigerant charge against manufacturer subcooling/superheat targets at current ambient conditions.PFN/A
• 33.Inspect all visible refrigerant line joints, flares, and service ports for oil residue indicating a slow leak.PFN/A
• 34.Test high- and low-pressure safety cutout switches at the field controller to confirm trip points match design.PFN/A
• 35.Verify compressor crankcase heaters are functioning and have had adequate soak time before first start of the season.PFN/A
• 36.Inspect and test reversing valves on heat-pump equipment for full-stroke operation and correct changeover.PFN/A
• 37.Confirm sight glass (where present) shows clear, bubble-free liquid line flow under stable load conditions.PFN/A
• 38.Verify TXV or EEV operation by observing superheat response to a deliberate load change.PFN/A
• 39.Inspect compressor mounting, isolators, and electrical connections for vibration-related wear or loosening.PFN/A
• 40.Record refrigerant type, total system charge, and any added/recovered refrigerant for EPA Section 608 recordkeeping.PFN/A

Heating equipment that has been idle for 6-8 months requires the most deliberate startup sequence of any system component — combustion safety devices in particular should never be assumed functional without a direct test.

• 41.Inspect burner assembly, igniter, and flame sensor for corrosion or carbon buildup; clean per manufacturer procedure.PFN/A
• 42.Test flame failure / flame rollout safety shutoff by simulating a no-flame condition and confirming lockout.PFN/A
• 43.Perform combustion analysis (O2, CO, CO2, stack temperature) at low and high fire; record results against manufacturer targets.PFN/A
• 44.Inspect heat exchanger for visible cracks, corrosion, or signs of flue gas leakage into the supply airstream.PFN/A
• 45.Verify gas supply pressure (inlet and manifold) matches nameplate specification under firing load.PFN/A
• 46.Inspect venting and combustion air intake for blockage, corrosion, or improper clearance to combustibles.PFN/A
• 47.Test high-limit temperature safety control and confirm it shuts down the burner at the correct setpoint.PFN/A
• 48.Inspect boiler low-water cutoff (where applicable) by manually lowering water level and confirming safe shutdown.PFN/A
• 49.Verify electric heat strip stages (where installed) energize in correct sequence without nuisance tripping of breakers.PFN/A
• 50.Confirm heating-mode changeover and outdoor air lockout setpoints are programmed for the upcoming heating season.PFN/A

These items protect people and the building, not just comfort or efficiency. A Fail on any item in this section should hold the unit out of service until corrected — do not defer life-safety findings to a future visit.

• 51.Test duct smoke detectors (supply and return) by introducing test smoke or using the manufacturer test feature; confirm unit shutdown.PFN/A
• 52.Verify fire/smoke damper actuators fully close on a simulated alarm signal and reset cleanly afterward.PFN/A
• 53.Inspect electrical disconnects, contactors, and terminal connections for heat discoloration, pitting, or loose lugs.PFN/A
• 54.Megohm-test compressor and major motor windings; record insulation resistance and flag any reading trending downward.PFN/A
• 55.Verify emergency shutdown (EPO) and fire alarm interlock shuts down associated air handling equipment as designed.PFN/A
• 56.Inspect grounding and bonding connections at all major equipment for corrosion or mechanical damage.PFN/A
• 57.Confirm CO and refrigerant-leak detection sensors (where required by code) are within calibration date and alarm correctly on test.PFN/A
• 58.Verify panel-mounted overcurrent protection (breakers/fuses) matches equipment nameplate MCA/MOCP — no field substitutions.PFN/A
• 59.Inspect mechanical room ventilation and emergency lighting required for equipment rooms housing refrigerant or combustion equipment.PFN/A
• 60.Confirm a current set of as-built control sequences, safety test records, and this completed checklist are filed with building records.PFN/A