Control panel displays Sn2 and spa may not heat or may shut down.

Safety first: Shut off power at the GFCI breaker before removing any panels or touching wiring.

• 1. Allow spa to cool: If the spa has been running for a long time or in hot weather, let it sit with power OFF for 30–60 minutes to cool the heater manifold.
• 2. Access the equipment bay: Remove the front panel to expose the PDC Spas control pack and heater tube. Locate the secondary or hi-limit sensor on or near the heater.
• 3. Inspect wiring and connector: Follow the sensor cable to the control board. Unplug and re-seat the connector. Look for corrosion, moisture, or burnt spots on the plug or board.
• 4. Check for dry-fire or flow issues: Verify that the spa has proper water level and that the circulation pump is operating. A lack of flow can overheat the heater and trigger Sn2. Check that all slice valves are open and filters are not clogged.
• 5. Replace the sensor if defective: If Sn2 returns immediately on a cool spa and wiring looks good, replace the PDC Spas hi-limit/secondary temperature sensor with an exact replacement. Turn power OFF, remove the sensor from the heater tube or manifold, install the new sensor with proper sealing, and reconnect to the board.
• 6. Test operation: Restore power and run the spa. Confirm that Sn2 does not reappear and that the heater cycles normally.

Call a technician if: The new sensor does not resolve the error or the heater manifold shows signs of melting, scorching, or repeated overheat. This may indicate a control board or heater relay fault.