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My AC Won't Turn On At All

When an air conditioner does nothing at all, the cause is more often power or a safety switch than a broken part. Check the breaker, the thermostat batteries, the condensate float switch and the furnace door switch before assuming the worst. Those four account for a large share of the no-cooling calls we run.

Work through these in order

  • The breaker for the air handler and the one for the outdoor condenser. A tripped breaker must be pushed fully OFF before it will reset ON.
  • Thermostat batteries. A dying battery can leave the display lit but the relay unable to close.
  • The condensate float switch. When the drain backs up, this switch cuts the system deliberately to stop water damage.
  • The furnace or air handler door. Most units have a safety switch that will not let the blower run with the panel off.
  • The outdoor disconnect box near the condenser, which is sometimes switched off after other work and never switched back.

A breaker that keeps tripping is telling you something

Resetting a breaker once is reasonable. If it trips again, stop. A repeated trip means the circuit is drawing more current than it should, which points to a failing compressor, a shorted capacitor or a wiring fault. Continuing to reset it is how a repair becomes a replacement.

What we do on a no-cool call

A Cool Guy checks the power path first, then the controls, then the equipment, and tells you what the fix costs before starting. The $49 dispatch fee comes off when you move forward with the repair.

FAQ

Common questions

Why did my AC stop working suddenly?

Most sudden no-cooling failures are a tripped breaker, dead thermostat batteries, a condensate float switch that cut the system because the drain backed up, or an open equipment door switch.

Should I keep resetting the breaker?

No. One reset is reasonable. If it trips again the circuit is drawing too much current, which usually means a failing compressor or capacitor, and repeated resets can turn a repair into a replacement.

What is a condensate float switch?

It is a safety switch that shuts the system off when the condensate drain backs up, so the overflow does not damage your ceiling or flooring. It is doing its job when it trips.

Reviewed by Briton Davis, owner, and the Cool Guys Home Services service team · Licensed, bonded & insured (CSLB #1156890)

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