Boiler frequently cycles on and off, rooms never reach set temperature

Safety: No immediate safety risk, but can reduce efficiency and component life.

• Check thermostat position: Ensure the room thermostat is not near a heat source or in a draught.
• Open some TRVs fully: Ensure at least a few radiators are fully open to provide adequate flow.
• Adjust boiler output: On many Vaillant models, maximum CH output can be reduced via installer menu; ask an engineer to set this appropriately for your property.
• Consider advanced controls: Vaillant eBUS controls (e.g. sensoHOME, vSMART) can modulate boiler output and reduce cycling.