Coleman air conditioner runs but does not cool the space adequately; supply air feels only slightly cooler than room air.

Safety: Turn OFF power before cleaning coils or opening panels. Refrigerant work must be done by a licensed technician.

• Check filter and vents: Replace the air filter and ensure all supply and return vents are open and unobstructed.
• Clean indoor coil: Access the evaporator coil in the Coleman air handler. Clean with an appropriate coil cleaner if dirty.
• Clean outdoor coil: Remove debris and wash the condenser coil as described earlier.
• Measure temperature drop: With the system running for 15–20 minutes, measure the temperature at a return grille and a nearby supply vent. A typical drop is 15–20°F. If much lower, airflow may be restricted; if much higher, refrigerant charge may be incorrect.
• Call a technician for refrigerant issues: If coils are clean and airflow is good but cooling is still weak, a Coleman-certified technician should check refrigerant pressures, locate leaks, and recharge the system.

Note: Oversized or undersized equipment relative to the home can also cause comfort issues; a load calculation may be needed.