System displays CH34 and shuts down, often during extreme temperatures or heavy load.

Safety: Turn off power before cleaning or inspecting units.

Steps:

• Improve airflow: Clean indoor filters and coils, and ensure outdoor unit has clear airflow on all sides.
• Check operating conditions: Avoid operating the system with doors/windows open or under extreme conditions outside the rated range.
• Power reset: Turn power off for 15–20 minutes to allow components to cool, then restore and test.

Technician involvement: If CH34 recurs frequently, a technician should check refrigerant charge, compressor current, and system pressures to identify underlying causes.