Boiler cycles on and off rapidly without reaching set temperature.

Safety first: Ensure safe access to controls and pipework.

• Check radiator valves: Make sure enough radiators are open to allow proper flow; do not close all TRVs in the property.
• Adjust pump speed: Reduce pump speed if flow is excessively high, causing rapid temperature rise.
• Review control settings: Lower the flow temperature setpoint or adjust weather-compensation curve to reduce overshoot.
• Hydraulic balancing: Consider balancing the system to distribute flow evenly.

When to call a professional: If short cycling persists, a heating engineer should review system design and boiler sizing.