Safety: Power troubleshooting involves hazardous voltages. If you are not comfortable, contact a licensed electrician or spa technician.

Step 1 – Check GFCI: Locate the spa's GFCI breaker or disconnect. Reset it fully OFF then ON. If it trips immediately, there may be a short in the spa.
Step 2 – Verify house power: Confirm other circuits in the panel are working and that there is no general power outage.
Step 3 – Inspect control pack fuse: With power off, open the equipment bay and remove the control pack cover. Look for a main fuse (often glass or cartridge style). Replace only with the same rating if blown.
Step 4 – Check wiring connections: Verify that the incoming power wires are tight at the spa's terminal block and match the Catalina wiring diagram (L1, L2, N if used, and ground).
Step 5 – Board failure: If correct voltage is present at the spa but the control pack remains dead, the internal power supply or board is likely failed and the spa pack may need replacement.

Spa will not power on at all; topside display is blank and no pumps run.

Possible Causes