Poolex pool heater shows F6 and will not run; may occur immediately at startup.

Safety: Turn off all power to the Poolex unit before opening the top or side panels.

Steps:

• Locate ambient sensor: Typically clipped to the evaporator coil or mounted near the air intake grille. It is a small probe with two wires.
• Inspect for damage: Look for cracked insulation, chewed wires, or a sensor hanging loose from its clip.
• Dry moisture: If the sensor or connector is wet, dry it thoroughly and allow the unit to sit powered off for at least 30 minutes.
• Reconnect: Reseat the sensor connector on the main PCB.

Replacement:

• Order a Poolex ambient air NTC sensor compatible with your model.
• Remove the old sensor from its clip or bracket and disconnect the wiring.
• Install the new sensor in the same location and route the cable away from fan blades and sharp edges.
• Restore power and verify that F6 is cleared.

If the error remains, the main control board may misread the sensor and require professional diagnosis.