AZ Checklists
AC Maintenance Checklist 2025: Stay Cool & Reduce Energy Bil

AC Maintenance Checklist 2025: Stay Cool & Reduce Energy Bil

Comprehensive air conditioning maintenance checklist covering safety, filters, coils, electrical systems, refrigerant, and performance testing.

AC Maintenance Checklist

Complete air conditioning maintenance checklist covering all essential AC system components including safety procedures, filter maintenance, coil cleaning, electrical systems, refrigerant checks, and performance testing for optimal cooling efficiency.

1. Pre-Maintenance & Safety Precautions

1Turn off AC unit and disconnect power (breaker or switch)
2Use proper personal protective equipment (gloves, goggles, etc.)
3Wait for the unit to cool down before servicing
4Ensure ladder or access point is stable and safe
5Keep a clear workspace around the unit (remove clutter)
6Label wires or take photos before disconnection
7Check for signs of pests, insects, or animals inside unit
8Use a non-contact voltage tester to verify power is off
9Have required tools and cleaning supplies ready
10Keep manufacturer's manual and wiring diagrams accessible

2. Air Filters & Airflow

1Inspect filters for dust, debris, or damage
2Clean reusable filters (wash, dry, and reinstall)
3Replace disposable filters if clogged or past service life
4Check filter frame and housing seals for gaps
5Verify correct filter size and orientation
6Ensure airflow path (vents, grills) is unobstructed
7Check whether airflow seems weak or restricted
8Inspect return air grilles for dust buildup
9Measure static pressure drop across filter (if instrument available)
10Note filter change date and schedule next replacement

3. Indoor (Evaporator) Coil & Drainage

1Inspect the evaporator coil for dirt, mold, or fouling
2Clean the coil with suitable coil cleaner / mild detergent
3Straighten bent fins (using fin comb)
4Check the drain pan for standing water or corrosion
5Clean or flush the condensate drain line
6Ensure drain trap or P-trap is functioning
7Use compressed air or a vacuum to clear clogs
8Check for algae, slime, or mold in drain path
9Confirm drain slope is adequate toward outlet
10Test draining by pouring water and observing flow

4. Outdoor (Condenser) Unit & Coils

1Clear vegetation, debris, leaves, or obstructions around the unit
2Inspect condenser coil surfaces and fins
3Clean condenser coil with water (gentle spray) or coil cleaner
4Straighten bent fins on the condenser side
5Verify the condenser casing is intact and secured
6Check top of unit for foreign objects or nesting material
7Ensure sufficient clearance (e.g. 12–24 in) on all sides
8Confirm fan guard is secure and undamaged
9Inspect condenser fan blades (damage, balance)
10Check that the outdoor unit is level and firmly anchored

5. Fans, Motors & Moving Parts

1Inspect blower fan (indoor) for dust accumulation
2Clean blower wheel or fan blades
3Check blower motor mountings and alignment
4Lubricate bearings, shafts, and moving parts (if design allows)
5Check condition of belts (for belt-driven systems)
6Adjust or replace worn / loose belts
7Ensure fan blades rotate freely without rubbing
8Measure motor amperage draw (compare to nameplate)
9Check for unusual noise or vibration during fan operation
10Confirm fan speed settings per manufacturer specs

6. Electrical & Control Systems

1Inspect all electrical wiring and terminations for corrosion or damage
2Tighten loose connections and terminals
3Check contactors, relays, and control switches
4Measure voltage and current on motors, compressor, etc.
5Inspect capacitors (start, run) and test their microfarad values
6Inspect control board or circuit board for signs of overheating
7Verify correct operation of safety and limit switches
8Inspect fuses, breakers, or overload protection devices
9Check and test electrical grounding and bonding
10Test wiring insulation resistance (if you have insulation tester)

7. Refrigerant System & Piping

1Inspect refrigerant lines and run for damage, corrosion, or insulation degradation
2Verify refrigerant charge (pressure test per manufacturer)
3Check for leaks (use leak detector or soap solution)
4Inspect suction and liquid line insulation
5Observe refrigerant line temperatures (superheat / subcooling)
6Confirm condenser and evaporator pressures under normal load
7Check and service service valves and access ports
8Ensure proper spacing and bending radius on pipes
9Look for oil stains or residue indicating leaks
10Verify that refrigerant matches manufacturer specifications

8. Thermostat & Controls

1Calibrate thermostat if possible; compare to actual room temp
2Inspect wiring to thermostat for damage or loose terminals
3Replace thermostat batteries (if used)
4Confirm mode switching (cool, off, auto) functions correctly
5Check delay timers / time-off settings / anti-short-cycle features
6Ensure thermostat is not exposed to heat sources or sunlight
7Test fan control (on / auto)
8Verify setpoints are working (e.g. set to cooler, unit engages)
9Test zone controls or multiple thermostats if applicable
10Record thermostat gain or hysteresis settings

9. Ductwork, Vents & Distribution

1Inspect ducts for dust, mold, damage, leaks
2Seal duct leaks (with mastic or metal tape)
3Check insulation on ducts (especially in unconditioned spaces)
4Ensure vents / registers are clean and open
5Verify that supply and return grills are not blocked
6Measure temperature drop between return and supply in each zone
7Balance airflow to different rooms (using dampers)
8Inspect duct joints and connections for tightness
9Clean or vacuum duct interiors if excessive dust
10Check for strange odor or moisture in ducts

10. Performance Testing & Documentation

1Run full cooling cycle and observe system behavior
2Measure indoor and outdoor temperatures, and ΔT (temperature split)
3Record operating pressures and compare to design specs
4Check compressor and system current draw
5Monitor for abnormal noise, vibration, or overheating
6Confirm that system cycles on and off properly
7Check system recovery after power interruption
8Document all corrections or parts replaced
9Note service date, next scheduled maintenance, and recommendations
10Take before/after photos (especially for coils, wiring)
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