Troubleshooting a central AC
It's hot inside, and the AC won't come on.
Start at the thermostat and work outward: most of these take a minute. A tripped breaker is where you stop.
Before you call anyone
No cooling at all: check, understand, then stop
Work down in order. The gauge shows where you are: blue is yours to check, red is where you leave it to us.
Safe to check yourself
Check these first
From Trane's advice to owners. Tick each one off as you go.
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Source: Trane, AC Not Turning On, checked 2026-10-22.
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Source: Trane, AC Not Turning On, checked 2026-10-22.
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Source: Trane, AC Not Turning On, checked 2026-10-22.
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Source: Trane, AC Not Turning On, checked 2026-10-22.
Worth a visit from us
What it usually means
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A blocked condensate drain
Some systems carry a safety switch that shuts the AC down when the drain line backs up, so the water doesn't end up on your floor.
What we do: We clear the line, check the pan and the switch, and run the system until it drains freely.
Source: Trane, AC Not Turning On, checked 2026-10-22.
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A frosted coil
Dust on the indoor coil, or a clogged filter, can let it frost over, and the AC shuts itself off.
What we do: We find out why it froze, airflow or refrigerant, before it runs again.
Source: Trane, AC Not Turning On, checked 2026-10-22.
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A failed capacitor
Capacitors start the AC and keep it running. If the start or dual capacitor has gone bad, the unit won't turn on.
What we do: We test it with a meter and replace it if it has failed.
Source: Trane, AC Not Turning On, checked 2026-10-22.
Stop, and call
When to stop and call
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The breaker has tripped
Don't keep flipping it back on. Trane's advice is to call a professional: a breaker can trip because of a serious fault in the system.
Source: Trane, AC Not Turning On, checked 2026-10-22.
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The checks pass and it still won't start
That's ours. When you call, tell us what you've already checked and we'll start from there.
Source: Trane, AC Not Turning On, checked 2026-10-22.
Tell us what it's doing. We'll take it from there.
Call and describe the problem: the noise, the smell, the room that never warms up. Or book a visit online.
