Spa trips the GFCI breaker immediately or shortly after turning on

Safety first: Do not repeatedly reset a tripping GFCI. This indicates a potentially dangerous fault. If you are not qualified to work with high voltage, contact a professional.

Frequent GFCI trips usually mean current is leaking to ground.

• Visual inspection: With power off, inspect all wiring in the equipment bay for burns, melted insulation, or loose connections.
• Isolate components: Disconnect the heater, then restore power. If the breaker holds, the heater is likely the cause. Reconnect heater and disconnect pumps one at a time to isolate a faulty motor.
• Check for moisture: Look for water inside pump motors, junction boxes, or the control pack.
• Test GFCI: If no faults are found and the breaker still trips, have an electrician test or replace the GFCI breaker.

Because ground faults can cause shock or fire, component replacement and wiring repairs should be performed by qualified personnel.