Air conditioner runs but doesn't cool
Confirm the air side before the refrigerant side. Most "low on refrigerant" calls are airflow problems, and charging a system with restricted airflow hides the real fault.
Safety
Refrigerant work requires appropriate certification and recovery equipment. Venting refrigerant is unlawful in most jurisdictions. Verify current local regulations and the manufacturer instructions before performing work.
Step 1
Is indoor airflow adequate?
Check the filter and coil, then measure total external static pressure and compare it with the rating plate. Low airflow changes every refrigerant reading you are about to take.
De-energise before opening the blower compartment.
Common causes at this step
- Dirty filter
- Dirty evaporator coil
- Closed registers or dampers
- Undersized or restricted duct
- Incorrect blower speed
Background: Static Pressure and Duct Diagnostics
Local Code Notice
HVAC installation, venting, combustion air, ventilation air, gas piping, clearances, termination locations, electrical requirements, permits, and equipment requirements vary by jurisdiction and equipment. Always verify the applicable local codes, adopted code edition, regulations, permits, and manufacturer installation instructions before installation or service.