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AC Won't Turn On
in McKinney, TX
When you turn the thermostat down and nothing happens, the problem is usually electrical. McKinney sees heavy thunderstorms in the spring and early summer, and power fluctuations during those storms are hard on AC components. Sometimes it's something simple like a tripped breaker, and sometimes a key electrical part has failed.
Quick Answer
An AC that won't start is usually a tripped breaker, a failed capacitor, or a thermostat problem. In McKinney, power surges during summer thunderstorms trip breakers and blow capacitors regularly. Check the breaker first. If it's not that, call (361) 317-6400 because a failed capacitor means the motor can't start and continuing to try will burn it out.
Telltale Signs
Warning Signs to Watch For
- Thermostat shows a temperature but nothing happens when you lower the setting
- The outdoor unit is completely silent and the fan is not moving
- The indoor air handler does not come on at all
- A breaker in your electrical panel labeled AC or HVAC has tripped to the middle position
- The thermostat screen is blank or shows an error code
Root Causes
What Causes AC Won't Turn On?
Tripped Breaker or Blown Fuse
Air conditioners pull a lot of current, especially when they start up. During a McKinney thunderstorm, a power surge or a brief outage can trip the breaker for the AC circuit. If the breaker trips repeatedly after you reset it, that is a sign of a bigger problem and you should not keep resetting it.
The Fix
Breaker Reset and Electrical Inspection
Reset the breaker once and see if the system starts normally. If it trips again, a tech needs to check the disconnect, wiring, and the unit itself before you reset it a third time.
Failed Run Capacitor
The run capacitor gives the compressor and fan motors the boost they need to start and keeps them running. Capacitors in McKinney fail more often than in cooler climates because heat shortens their lifespan, and a capacitor running through temperatures above 100°F for weeks at a time wears out faster than the manufacturer's rating suggests. A failed capacitor means the motor hums but can't spin.
The Fix
Capacitor Replacement
A tech tests the capacitor with a meter and replaces it if it's out of spec. It's a fast repair when caught early, but running the unit with a weak capacitor burns out the motor it's supposed to protect.
Thermostat Failure or Dead Batteries
If the thermostat loses power or fails, it can't send the signal that tells the AC to turn on. Battery-powered thermostats in homes built in the 1990s across subdivisions like Stonebridge Ranch sometimes just need new batteries, but older thermostats also fail outright and need replacing.
The Fix
Thermostat Battery Replacement or Thermostat Replacement
A tech checks whether the thermostat is sending the correct signal to the system. If the thermostat is dead, replacing it with a compatible unit solves the problem.
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 Failure or Dead Batteries |
|---|---|---|---|
| Breaker for the AC is tripped to the middle position | |||
| Outdoor unit hums but fan won't spin | |||
| Thermostat screen is completely blank | |||
| Breaker is fine but unit still won't start | |||
| Unit tripped the breaker right after a storm | |||
| New batteries in thermostat didn't fix anything |
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