Keystone air conditioner shows H1 and may run the fan only or pause cooling, often in low ambient conditions.

Note: H1 on some Keystone models is a status indication rather than a fault; it means the unit is in defrost or anti-frost mode.

Steps:

• Allow defrost cycle: Let the unit run; H1 should clear automatically once the coil warms.
• Improve airflow: Clean the air filter and ensure supply and return vents are not blocked by curtains or furniture.
• Check room conditions: Avoid running COOL mode when the room is already very cold (near or below 60°F / 16°C).
• Inspect evaporator: If icing is frequent, clean the coil and verify the fan is running at proper speed. Replace the fan motor or capacitor if weak.