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AC not cooling or cooling weakly.

A trained tech should take airflow and electrical readings, and a refrigerant-credentialed technician should do gauge, charging and leak work.

Customers put it like this

  • The AC is blowing warm air
  • It runs but the house won't cool
  • The outside unit hums and shuts off
  • Last tech said it needs refrigerant
Prepare this job in ForeBotFind another guide

Stop first if

  • Water is on wiring, controls or a powered unitKeep clear of it. A qualified person kills power at the disconnect while standing somewhere dry. Otherwise call a licensed electrician.
  • A large refrigerant release happens in a small or low roomLeave the area and ventilate. Stay out of low spots. Call emergency services if anyone is overcome.
01

Ask on the call

6

Homeowner? These are the questions a good technician will ask you. Having the answers ready makes the first visit count.

  1. Is the system running, or completely dead?
  2. Is the air weak, or moving well but just warm?
  3. When was the filter last changed, and are the vents open?
  4. Do you see ice on the copper lines or indoor unit?
  5. Does the thermostat or unit show a code or blinking light?
  6. Has refrigerant been added before, and was a leak ever found?
02

Bring

5
  • Clean filter
  • Digital manometer
  • Clamp-on current meter
  • Probe thermometers
  • Gauge set rated for the refrigerant
03

Check on site

6
  1. Record indoor and outdoor models, refrigerant, metering type and any code. Wait out any start delay the maker documents.
  2. Check filter, registers, coil faces and blower before touching the refrigerant side.
  3. Once the system settles, record the temperature drop across the indoor coil.
  4. Read external static pressure and compare with the maker's blower table.
  5. A qualified tech clamps compressor current and notes discharge line temperature, with no contact on terminals.
  6. Only a tech with the required refrigerant credential attaches gauges. Treat low charge as a leak until shown otherwise.
04

Keep on the record

5
  • Filter condition photo
  • Temperature drop across the coil, with outdoor temperature
  • Static pressure readings
  • Compressor current
  • Nameplate photos and any code

General guidance for a qualified person, not a finding about any home. The person on site decides.