AC Won't Turn On in Chattanooga
Nothing at all - no fan, no hum, no cold. Before you pay for a diagnostic, three of the usual causes cost nothing to check.
In Chattanooga, a significant share of dead air conditioners are stopped by a safety float switch that shut the system off because the condensate drain is clogged, and clearing that drain typically costs $110-260.
A diagnostic visit in the Chattanooga area runs $80-150 and is commonly waived when the repair is carried out on the same visit.
A thermostat replacement in the Chattanooga area runs $150-400 installed, depending on whether it is a basic or a smart model.
Check these four first - they are free
- The breaker. Look for one sitting between ON and OFF, not fully tripped. Push it firmly OFF and then back ON. If it trips again immediately, stop and call - a breaker that trips repeatedly is telling you about a short, not about itself.
- The condenser disconnect. This is the small grey box on the wall beside the outdoor unit. Yard crews and anyone doing exterior work pull it and forget to reseat it.
- The float switch. There is a small safety switch on the condensate drain line at the indoor unit. If the drain clogs and water backs up, this switch deliberately kills the whole system to stop it flooding your ceiling. In humid Chattanooga summers this is a genuinely common cause of a dead AC.
- The thermostat batteries. Some models go completely blank rather than warning you.
Why the float switch catches people out
It feels like a total system failure - nothing responds at all - and it is actually the system protecting your house. In this climate an air conditioner pulls gallons of water out of the air every day, and that water has to go somewhere. When algae or dust blocks the drain line, the pan fills, the float rises, and the switch cuts power.
Homeowners who do not know this switch exists sometimes pay for a full diagnostic to be told their drain is dirty. That is why it is on this page: knowing to look is worth $80-150 to you.
When it is not free
| Cause | Typical Chattanooga cost |
|---|---|
| Clogged condensate drain | $110-260 |
| Failed thermostat | $150-400 |
| Failed contactor | $160-320 |
| Failed transformer or control board | $250-700 |
| Failed blower motor | $420-950 |
Common questions
The breaker keeps tripping. Can I just keep resetting it?
No. A breaker that trips repeatedly is doing its job against a real fault, usually a shorted compressor winding or damaged wiring. Repeatedly resetting it is how an electrical fault becomes a fire.
Indoor fan runs but the outdoor unit is dead. What is that?
That points to the contactor, the capacitor, or the outdoor disconnect rather than to the thermostat or the drain. Expect $160-330 for the common cases.
Can I clear the condensate drain myself?
Often yes. A wet-dry vacuum on the outdoor end of the drain line will pull the blockage out. If the line is fully clogged with algae or the pan is already overflowing, get someone out before it reaches drywall.