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AC Won't Turn On
in Richardson, TX
Richardson's spring storms regularly knock out power and send voltage spikes through homes, and those spikes trip breakers and kill capacitors in AC systems. A system that won't turn on at all can mean something simple or something serious, and you won't know which until someone checks it. Letting the problem sit means the house heats up fast, especially in June and July when overnight lows barely drop below 75.
Quick Answer
When an AC won't start at all, it's usually a tripped breaker, a blown fuse, a failed capacitor, or a thermostat that lost power. Start with the breaker panel and thermostat batteries. If those check out, a technician needs to test the electrical components inside the unit. Call (361) 202-9465 before you spend a night in the heat waiting to find out it was something simple.
Telltale Signs
Warning Signs to Watch For
- The thermostat shows cooling mode but neither the indoor nor outdoor unit starts
- You can hear a faint click or hum from the outdoor unit but nothing spins
- The breaker for the AC has tripped to the middle position
- The thermostat screen is blank or shows a low battery warning
- The outdoor unit starts but the indoor air handler does nothing
Root Causes
What Causes AC Won't Turn On?
Tripped Breaker or Blown Fuse
AC systems draw a large surge of power when they start up, and a voltage spike from a storm or a momentary overload can trip the breaker. The disconnect box near the outdoor unit also holds fuses that blow when the system is overloaded. Richardson sees 50 to 60 thunderstorm days a year on average, and each one is a chance for a power event to knock out the AC.
The Fix
Breaker Reset or Fuse Replacement
A technician resets the breaker or replaces the fuse and then monitors the system to make sure the same fault doesn't trip it again. A breaker that trips repeatedly means something else is wrong.
Failed Run Capacitor
The run capacitor is a small cylinder that gives the motors in the outdoor unit the jolt they need to start spinning. When it fails, the motors hum but don't turn over, and the system quickly shuts off on a safety switch to avoid burning up the motor. Capacitors wear out faster in the heat, and units in Richardson that run 8 or 9 months a year go through them faster than units in cooler climates.
The Fix
Capacitor Replacement
A technician tests the capacitor with a meter and replaces it if it's out of spec. It's a straightforward repair that restores normal starting immediately.
Thermostat or Control Board Failure
The thermostat sends a signal to the control board, which tells the system to start. Dead batteries, a wiring fault, or a failed control board can break that signal and leave the system completely unresponsive. Homes in the Arapaho Road corridor that still use original builder-grade thermostats from the 1990s are especially prone to this, since those units are well past their expected lifespan.
The Fix
Thermostat or Control Board Replacement
After testing both the thermostat and the board, the technician replaces whichever component failed. A new programmable thermostat is a reasonable upgrade at the same time, since the old one is likely at end of life anyway.
Self-Diagnosis
Which Cause Applies to You?
Check the signs you're observing to narrow down the likely root cause before your inspection.
| What You're Seeing | Tripped Breaker or Blown Fuse | Failed Run Capacitor | Thermostat or Control Board Failure |
|---|---|---|---|
| Outdoor unit hums briefly then goes quiet with nothing spinning | |||
| Thermostat screen is blank | |||
| Breaker is in the tripped position | |||
| Indoor unit runs but outdoor unit does nothing | |||
| System was fine yesterday and went dead overnight after a storm |
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