You set the thermostat to Cool, waited, and nothing happened. No air moving, no compressor hum outside. Dead system.
You probably came here because…
- The thermostat screen may be blank or dim
- No air is moving from any vents in the house
- The outside unit is completely silent
- You may have heard a click and then nothing
What’s actually happening
A totally dead AC usually comes down to one of three power problems: a tripped breaker, a bad capacitor at the outdoor unit, or a blown low-voltage fuse on the control board.
A tripped breaker is your first suspect and the cheapest fix. The other two are cheap parts but need to be diagnosed carefully because a blown fuse or dead capacitor is usually a symptom of something else stressing the system.
If the thermostat itself is dead, the problem is upstream: the low-voltage transformer or the fuse that protects it.
What we do about it
Reset the breaker
Find your electrical panel. Look for a breaker labeled AC, HVAC, or Condenser. If it's tripped (sitting in the middle position), flip it all the way off, then back on. If it trips again immediately, stop and call us.
Check the thermostat
Blank screen means it's not getting power. If it's battery-powered, replace the batteries. If it's hardwired and dead, there's a fuse on the furnace or air handler control board that blew.
Listen at the outdoor unit
Set the thermostat to Cool at 65 and go stand next to the outdoor unit. You should hear a click and the fan should start within 60 seconds. If you hear a hum but no fan spin, the capacitor is dead.
When to just call
If the breaker trips again after reset, do not keep resetting it. Something is drawing too much current and you can damage the unit or start a fire. Call (423) 637-1846 same day.
Ready to fix it?
Call the family that’s been doing this in the Sequatchie Valley since 1996.