Nest thermostat causes short cycling: HVAC turns on and off frequently

Safety: Turn off power before inspecting filters or panels.

• Check filter: Replace a dirty or clogged air filter to prevent overheating and limit switch trips.
• Verify settings: Ensure the Nest is configured for the correct system type and stages. Avoid frequent manual temperature changes that can cause rapid cycling.
• Observe equipment: Watch the furnace or condenser during operation. If it shuts down quickly with error lights or unusual noises, there may be a system fault.
• Use longer setbacks sparingly: Large temperature swings can cause aggressive cycling as the system tries to catch up.
• Professional service: If short cycling persists, an HVAC technician should check for refrigerant issues, limit switch problems, or equipment oversizing.