F7 displayed, spa may shut down or run erratically

Safety first: This fault involves mains voltage. If you are not qualified, contact a licensed electrician or spa technician. Always turn off the breaker before opening the control pack.

• 1. Confirm supply voltage:
  • Check that the spa is wired according to the Wellis installation manual (e.g., 230–240 V single‑phase or 400 V 3‑phase where applicable).
  • Have an electrician measure voltage at the spa disconnect and at the spa terminal block under load.
• 2. Inspect wiring connections:
  • With power OFF, open the control pack and inspect the incoming power terminals.
  • Tighten any loose screws and look for discoloration or heat damage.
• 3. Check breaker and cable size:
  • Verify that the breaker and cable gauge meet Wellis specifications for your model’s total amperage draw.
• 4. If voltage is stable but F7 persists: The internal power supply on the main control board may be failing. Have the control pack tested and replaced by a professional.