HVACDIAGNOSTIC
Condition

AC Running Constantly in Extreme Heat

System never cycles off during peak summer temperatures. May indicate undersized unit, refrigerant, or thermostat.

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 →

Severely Clogged Air Filter

A dirty filter restricts airflow, putting strain on the blower motor and reducing efficiency.

Root Cause Analysis →
Repair Options
High-Efficiency Air Filter Replacement →

Dirty Evaporator Coils

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

Root Cause Analysis →
Repair Options
Evaporator Coil Cleaning →

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 →

Repair Options

AC Contactor ReplacementView Repair Manual →High-Efficiency Air Filter ReplacementView Repair Manual →Evaporator Coil CleaningView Repair Manual →Thermostat ReplacementView Repair Manual →

Related Components & Parts

contactorfilterevaporator coilthermostat

Other AC Running Constantly Conditions

AC Running Constantly After Filter ChangeAC Running Constantly Upstairs OnlyAC Running Constantly Intermittent
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