Coleman air conditioner displays E4 and may stop cooling; sometimes accompanied by ice on the indoor coil or suction line.

Safety: Turn OFF power at the thermostat and breaker before opening panels. Ice on the coil can cause water damage when it melts.

• Thaw the system: Turn the thermostat to OFF and set the fan to ON to circulate air. Allow several hours for all ice on the evaporator coil and suction line to melt. Place towels or a pan under the air handler if needed.
• Replace or clean filter: Locate the return-air filter in the Coleman air handler or return grille. Replace disposable filters or clean washable ones. A severely clogged filter is a common cause of E4.
• Inspect the evaporator coil: Remove the indoor coil access panel. Check for heavy dust or biological growth on the coil face. Clean with a coil cleaner designed for evaporators, following label directions.
• Check blower operation: With power restored, run the fan only. Confirm the indoor blower motor starts quickly and moves strong airflow from supply vents. If weak or intermittent, test the blower capacitor and inspect the Coleman blower motor.
• Check duct restrictions: Ensure supply and return registers are open and not blocked by furniture or rugs.
• Refrigerant issues: If E4 recurs after airflow issues are corrected, the system may be low on refrigerant due to a leak. A licensed technician must locate the leak, repair it, evacuate, and recharge the system to Coleman specifications.

Warning: Do not chip ice off the coil with tools; you can puncture the tubing.