Heater starts and stops frequently (short cycling) without maintaining a stable temperature.

Safety first: Turn off power before adjusting internal settings.

• Check setpoint and differential: Access the Nirvana service menu and verify the temperature differential (hysteresis) is set according to the manual. Increase slightly to reduce rapid cycling.
• Sensor location: Ensure the water temperature sensor is in a location with good water mixing, not in a dead leg or near the heater outlet where temperature swings are large.
• Flow balancing: Adjust valves to promote thorough mixing of heated water with pool water before it reaches the sensor.
• Automation conflicts: If using external controls, verify that the automation is not rapidly toggling the heater on and off due to overlapping schedules or setpoints.