Thermostat frequently cycles heating on and off (short cycling)

Safety first: No need to access mains wiring for this adjustment.

Steps to reduce short cycling:

• 1. Adjust hysteresis:
  • In advanced settings, increase the hysteresis (temperature difference between on and off) slightly (e.g., from 0.2°C to 0.5–1.0°C).
• 2. Check thermostat placement:
  • Ensure the thermostat is not in a draft or directly in the airflow of vents.
  • Drafts can cause rapid temperature fluctuations at the sensor.
• 3. Review control mode:
  • Some Fibaro thermostats allow PWM or on/off control modes.
  • Switching to a more suitable mode for your heating type can reduce cycling.
• 4. Verify system sizing:
  • If the heater is significantly oversized for the room, it may heat too quickly and shut off often; consult an HVAC professional if suspected.

When to call a professional: Persistent short cycling can reduce equipment life; an HVAC technician can assess system design and recommend changes.