High-pitched whine or humming noise from the Fairland inverter pool heater.

Safety: Turn off power before touching the unit.

Steps:

• Check mounting surface: If the heater is on a hollow deck or thin slab, place vibration pads under the feet to reduce resonance.
• Tighten panels: Secure any loose panels that may be vibrating.
• Observe operation: Note whether the noise changes with compressor speed or fan speed; this helps a technician diagnose.

If the noise is very loud or changes suddenly:

• Have a technician inspect the fan motor, compressor, and inverter board for bearing or electrical issues.