Capacitors rarely die without warning — they fade, and the fade has a signature. Catch it in shoulder season and it's a cheap, calm fix. Miss it and it's a 97°F Saturday emergency call. The seven signs, in the order techs usually meet them:
1. Hard starting
The AC hesitates, clicks, hums, and takes an extra beat to fire up. Weak caps deliver a weak starting torque.
2. The hum with no spin
Outdoor unit buzzing, fan blade frozen. Push the blade with a stick and it takes off? Classic capacitor.
3. Warm air with everything "running"
If the compressor can't start but the fans can, you'll get airflow without cooling.
4. Intermittent tripping breakers
This is the one that matters most: a struggling compressor pulls locked-rotor amps over and over, cooking its windings. A $20 capacitor ignored long enough becomes a compressor — and a compressor is often a new-system conversation.
5. The unit shuts off on hot afternoons only
Capacitance drops as temperature climbs. A cap at the edge fails exactly when you need it most.
6. Rising energy bills
Motors running off-spec draw more current for less work.
7. The bulged top
Pop the service panel (power off) and look: a domed or leaking capacitor has already told you everything.
Confirming it in 60 seconds
A multimeter with a capacitance setting settles it: measured MFD more than 6% below the rating printed on the can means replace. Our free capacitor test tool takes your two numbers and gives the verdict — plus the exact replacement spec.
⚡ Run the 60-Second Capacitor Test →
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