Jacuzzi pool heater will not start at all; no lights or display when power is turned on.

Safety first: Turn off power at the main panel before opening the heater. Verify with a non-contact voltage tester.

Steps to restore power:

• Check breaker and disconnect: Confirm the dedicated breaker for the Jacuzzi heater is ON and that any external disconnect switch is closed.
• Inspect wiring connections: Remove the access panel and verify that line voltage is present at the heater’s input terminals. Tighten any loose lugs.
• Check internal fuse: Many Jacuzzi heaters have a low-voltage or control fuse on the main board. Inspect and replace with the exact same type and rating if blown. Investigate why it blew (shorted wiring, surge).
• Test transformer: Measure the transformer’s secondary output. If there is no low-voltage output with proper input, replace the transformer with a Jacuzzi-approved part.

If you are not comfortable working with live electrical circuits, contact a licensed electrician or Jacuzzi technician.