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Video · AC Repair and Troubleshooting

AC Running but Not Cooling: Gauges, a Meter and the Coil

When an AC is running but not cooling, the usual causes are a dirty filter, a thermostat problem, a frozen evaporator coil, a dirty outdoor coil or low refrigerant. A tech's gauges and meter tell them apart.

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What you’re seeing in this video

Three SwiftPro techs work an outdoor condenser beside a townhouse in steady rain. One kneels at the service valves with refrigerant gauges hooked up, reading the system's pressures to see whether the charge is where it should be.

A second tech in a Trane hoodie holds multimeter probes on the wiring inside the Trane condenser's electrical panel, checking that voltage is reaching the parts that start the compressor and fan. A third works at the outdoor coil itself, the fins that let the unit dump the heat it pulled out of your house.

The text on screen runs through the common causes homeowners can check: a dirty air filter, thermostat settings, and a frozen coil.

Job footageSwiftPro
Topic
AC Repair and Troubleshooting
Length
0:36
Posted
October 11, 2026
Shot by
The SwiftPro crew, Northern Virginia

Why it matters in your house

  • If the outdoor fan spins but the air inside feels room temperature, check the filter and thermostat first. A clogged filter can freeze the evaporator coil and leave the house hot.
  • Ice on the big copper line at the outdoor unit means the indoor coil has frozen. Turn cooling off and run the fan to thaw it; running it frozen strains the compressor.
  • Low refrigerant isn't a top-off problem, it's a leak. Adding refrigerant without finding the leak means paying for the same fix again next summer.

Why is my AC running but the house is still hot?

Start with the easy stuff: a fresh filter, the thermostat set to cool a few degrees below room temperature, and the outdoor unit actually running. If all three check out, the coil may be frozen or dirty, or the system may be low on refrigerant from a leak. That's when gauges come out, because guessing at refrigerant makes it worse.

Want it done at your place? See AC Repair and Troubleshooting at SwiftPro or call (703) 997-9757.

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SwiftPro Heating, Cooling & Plumbing
4230 Lafayette Center Dr N, Chantilly, VA 20151
44679 Endicott Dr, Suite 211, Ashburn, VA 20147
Virginia Class A contractor license #2705192276

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