Thermostat causes boiler to short-cycle (frequent on/off) leading to noise and inefficiency.

Safety: No internal wiring changes are needed for this adjustment.

• Step 1 – Adjust cycle settings:
  • In the installer menu, increase the temperature differential or cycle time to reduce on/off frequency.
• Step 2 – Enable minimum run time (if available):
  • Set a minimum burner on-time to prevent rapid cycling.
• Step 3 – Improve thermostat location:
  • Move the thermostat away from drafts or direct sunlight that cause rapid temperature swings.
• Step 4 – Check boiler modulation:
  • Ensure the boiler is set to modulating mode with eBUS/OpenTherm if supported.
• Step 5 – Consult heating engineer:
  • If cycling persists, system design (e.g., an oversized boiler) may need professional review.