HVAC SOP Example

Central A/C Seasonal Tune-Up & Refrigerant Check

Annual cooling system tune-up covering coil cleaning, electrical inspection, refrigerant verification, and service report.

1. Pre-work documentation & safetyDocument system nameplate data: model, serial number, refrigerant type (R-410A), and nominal charge weight. Photograph both indoor and outdoor unit condition before any work. Verify system is OFF at the thermostat before opening any panels. Switch off the outdoor disconnect and tag. Note ambient temperature — accurate refrigerant readings require ambient above 55°F for cooling checks. Record customer complaint details: slow to cool, warm rooms, or specific symptoms in service ticket before beginning diagnostics.
2. Indoor unit inspection — evaporator & drainRemove the air handler access panel. Inspect the evaporator coil face for ice, dirt loading, or biological growth. A heavily dirty evaporator coil is the most common cause of poor cooling performance — photograph and document condition. Inspect the drain pan for standing water, algae, or overflow evidence. Pour 1 cup of water into the drain pan and confirm it drains freely. Clear drain line blockage with a wet-dry vacuum at the exterior termination. Flush with a mixture of water and distilled white vinegar. Check blower wheel for dirt buildup and inspect the filter — a clogged filter causes both icing and underperformance.
3. Condenser unit inspection & coil cleaningRestore power to the outdoor unit and allow system to operate for 10 minutes before taking refrigerant readings. Then shut down again for coil cleaning. Remove condenser cabinet panels — inspect coil fins for bending, debris accumulation, or rodent damage. Apply approved foaming coil cleaner to all exposed condenser coil surfaces. Allow 10-minute dwell time. Rinse from inside to outside using low-pressure garden hose — never use pressure washer on condenser coils. Straighten any significantly bent fins with a fin comb. Inspect the fan blade for cracks or chips and verify it spins freely.
4. Electrical component inspectionWith power confirmed off and capacitor discharged (use a 20kΩ bleed resistor), remove and test the run capacitor with a digital capacitance meter. Capacitor must read within ±6% of nameplate microfarad rating — replace if out of tolerance. Inspect the contactor: examine contact tips for pitting, carbon tracking, or welding. A contactor with more than 30% pit depth should be replaced. Inspect all wiring for cracked insulation, corroded terminals, or loose connections. Tighten all electrical connections per manufacturer torque specs. Photograph all component conditions.
5. Refrigerant charge verificationRestore power and operate system in cooling mode. Allow the system to run for minimum 15 minutes to reach stable operating conditions. Attach manifold gauges to the service ports — use only R-410A rated gauges (800 PSI minimum). Measure suction line temperature with a clamp thermometer at the service port. Calculate superheat (for fixed-orifice systems) or subcooling (for TXV systems) per manufacturer spec. Suction pressure and temperatures must correlate to expected values given the ambient conditions. If charge is low, locate and repair any refrigerant leak before adding refrigerant — EPA Section 608 requires leak repair before recharge on systems above 5 tons.
6. Airflow & temperature split verificationMeasure supply and return air temperatures at the air handler with a digital thermometer. A properly functioning system should deliver a temperature split (delta-T) of 15–22°F across the coil under design conditions — lower split indicates undercharge, dirty coil, or low airflow. Measure external static pressure with a manometer — compare to blower performance data for the unit. Check all accessible supply registers for balanced airflow. If significant imbalance exists, note in service report and recommend duct assessment.
7. Service report & customer communicationComplete service report documenting: all readings (suction/discharge pressure, superheat or subcooling, supply and return temperatures, static pressure, capacitor readings, amperage), all components inspected and their condition, any refrigerant added (quantity and reason per EPA records), repairs made, and any recommended follow-up items. Walk the customer through findings before leaving — explain any items flagged for future attention. Leave a copy of the service report with the customer and ensure they understand the filter change schedule to prevent recurrence.