Heater starts then stops after a few minutes without showing an error code; cycle repeats frequently.

Safety: Ensure safe access around the unit; no special electrical work is required for basic checks.

Steps:

• Check sensor location: Confirm the Fairland water temperature sensor is installed where it measures mixed pool water, not directly at the heater outlet.
• Increase hysteresis: If the controller allows, increase the temperature differential (on/off span) to reduce rapid cycling.
• Review external controls: If connected to automation, ensure it is not sending rapid on/off commands.

If short cycling continues:

• A technician may need to relocate sensors, adjust control parameters, or evaluate whether the heater capacity is appropriate.