The AC quit and it is 115 outside.

In most of the country a broken air conditioner is a comfort problem. In Phoenix in July it is a safety problem first, so deal with that order.

Keep people safe first

Decide who is at risk. Infants, anyone elderly, anyone on medication affecting hydration or temperature regulation, anyone with heart or lung conditions, and pets. If somebody in the house is in those groups, moving them somewhere cool beats waiting on a repair.

Maricopa County operates cooling and hydration centres through the summer. A library, a mall or a cinema works too.

Drink water before you are thirsty. Thirst lags dehydration.

Know the signs. Cramps, heavy sweating, dizziness, nausea and headache mean cool down and hydrate now. Confusion, hot dry skin with no sweating, or fainting is an emergency. Call 911.

Make the house less bad

Close everything on the sun side. Blinds, curtains, blankets over west windows if it comes to that. Radiant gain through glass is enormous here.

Move to the lowest, most interior room. Heat stratifies and the roof is the hottest surface on the house.

Fans, but understand what they do. Moving air helps you lose heat by evaporation while the air is cooler than your skin. Above roughly body temperature a fan blowing hot air at you stops helping, so pair it with water on the skin.

Stop making heat. Oven off, dryer off, as few lights as possible.

Open up at night, close at dawn. In July overnight lows may not be low enough to help. In May and September they are.

The ten minutes of checks

Worth doing while you are waiting, because several outcomes are free.

1. Thermostat on COOL, fan on AUTO, setpoint below room temperature, batteries good.
2. Breaker. Reset once. If it trips again, leave it off and read the breaker guide.
3. The disconnect outside, seated.
4. The drain pan. A tripped float switch kills the system with no other symptom, and it is the most commonly missed cause.
5. Outside: is the fan spinning, is the compressor humming, are the fins packed with dust.

Write down what you find. Those five answers shorten the phone call enormously, and sometimes end it.

What to say when you call

The symptom in one sentence, what you already checked, the brand off the outdoor unit, and whether anybody in the house is at risk from the heat. That last one matters and it is worth leading with.

Most faults can be narrowed down on the phone. If it is a capacitor or a contactor it is a flat price off the published list, and you hear the number before anything gets touched.

What not to do

Do not keep resetting a breaker that keeps tripping. Do not bypass a float switch to get cooling back. Do not run a system with ice on it, because that is how a cheap fault becomes a compressor. And do not sit in a 110 degree house all afternoon to save a trip to somewhere cool.