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SN2

Sundance Hot Tub

Severity: Moderate

Source: OnlyErrorCodes.com — Every error code. One place.

Sundance Spa SN2 Error — Temperature Sensor Fault

What Does This Error Mean?

SN2 indicates the water temperature sensor has failed — the sensor that tracks current water temperature for heater control.
The control system can't manage heating without an accurate reading and disables it.
Sensor replacement (80–150 USD parts plus labor) is the typical fix.
The spa won't heat until SN2 is cleared.

Affected Models

  • Sundance Optima
  • Sundance Cameo
  • Sundance Maxxus
  • Sundance Constance
  • Sundance Capri

Common Causes

  • Water temperature sensor failed
  • Sensor coated with calcium deposits causing false low reading
  • Sensor wire damaged or disconnected
  • Connector loose at the controller
  • Controller sensor input damaged

How to Fix It

  1. Power off at the breaker.

    Switch the spa breaker off.
    Wait 60 seconds for capacitors to discharge.
    Don't try to work on sensors with power live.

  2. Open the equipment access panel.

    Find the equipment access panel on the side of the spa cabinet.
    Open it to expose the control pack.
    The temperature sensor wires connect to a specific socket on the controller — check Sundance documentation for your model's layout.

  3. Inspect the sensor and wiring.

    Look at the sensor itself.
    Heavy calcium buildup can be cleaned with vinegar soak.
    Check wires for damage.
    Reseat the controller connector — sometimes vibration loosens it over years.

  4. Schedule Sundance service.

    If basic inspection doesn't reveal a clear fix, schedule service.
    Sundance-authorized techs have OEM sensors and the diagnostic tools to confirm.
    Cost: 100–200 USD all-in for a sensor swap.
    Don't use generic sensors — Sundance controllers are tuned for specific characteristics.

  5. Don't run the spa with SN2 active.

    Without working temperature feedback, the heater can't be controlled safely.
    Don't try to override or bypass.
    The protection is intentional.
    Wait for repair before resuming use.

Frequently Asked Questions

What's the difference between SN1 and SN2?

SN1 is the high limit (safety) sensor — protects against overheat.
SN2 is the water temperature (regulating) sensor — provides reading for heater control.
Both are critical and both must work for safe operation.
Different sensors, similar repair process — just different parts.

Can hard water shorten sensor life?

Yes — calcium buildup on the sensor probe insulates it from accurate water temperature reading.
Eventually the sensor reads inconsistently and the controller flags SN2.
Annual descaling with a spa-safe product extends sensor life and prevents repeat SN2 events in hard water areas.