Boiler short cycles, turning on and off frequently without satisfying thermostat

Safety first: Turn off power before changing internal control settings.

• Check thermostat location: Ensure the thermostat is not near heat sources, drafts, or direct sunlight, which can cause rapid cycling.
• Review control settings: On Burnham controls, adjust the differential or anti-cycling time (if available) to allow longer run times between starts.
• Verify flow: Make sure all relevant zone valves are open and circulators are operating so the boiler sees enough load.
• Consider outdoor reset: If not already enabled, using the outdoor sensor and reset curve can reduce cycling by matching water temperature to load.
• Consult a professional: If the boiler is significantly oversized, a technician may recommend control strategies or system modifications to reduce cycling.