Ariston water heater frequently cycles on and off, even when no hot water is being used.

Safety first: Turn off power before accessing thermostat.

• Check for hot pipe thermosiphon: Feel the hot outlet pipe when no water is used. If it is hot far from the heater, install a check valve or heat trap to prevent natural circulation.
• Insulate pipes: Add insulation to hot water pipes near the heater.
• Verify thermostat operation: Replace a thermostat that cycles excessively or has a very narrow differential.