HVACDIAGNOSTIC
Condition

AC Running Constantly After Filter Change

Continuous operation persists after replacing the filter. Points to thermostat, contactor, or refrigerant.

Possible Causes

Welded AC Contactor

Electrical arcing can 'weld' the contactor shut, causing the outdoor unit to run constantly.

Root Cause Analysis →
Repair Options
AC Contactor Replacement →

Incorrect Thermostat Calibration

If the thermostat fails to sense the correct temperature, it won't signal the HVAC to run.

Root Cause Analysis →
Repair Options
Thermostat Replacement →

Dirty Evaporator Coils

Dust buildup on the coils restricts airflow and stops heat absorption.

Root Cause Analysis →
Repair Options
Evaporator Coil Cleaning →

Repair Options

AC Contactor ReplacementView Repair Manual →Thermostat ReplacementView Repair Manual →Evaporator Coil CleaningView Repair Manual →

Related Components & Parts

contactorthermostatevaporator coil

Other AC Running Constantly Conditions

AC Running Constantly in Extreme HeatAC Running Constantly Upstairs OnlyAC Running Constantly Intermittent
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