Sn3
MAAX Spas Auxiliary Sensor Fault (Cabinet / Ambient / Optional Sensor)

Display shows Sn3 or SN3; spa may behave erratically or shut down.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Failed auxiliary sensor, Disconnected sensor harness, Incorrect sensor type installed, Control board sensor input failure

How to Fix / Troubleshooting

Safety: Disconnect power before inspecting sensors or the control pack.

  • Identify sensor: Consult the MAAX wiring diagram inside the equipment bay to locate the Sn3-designated sensor (often ambient or cabinet sensor).
  • Check harness: Ensure the sensor plug is fully seated on the correct header on the control board.
  • Inspect cable: Look for damage, especially where the cable passes through cabinet openings.
  • Test with known-good sensor: If available, temporarily connect a known-good MAAX auxiliary sensor to see if the error clears.
  • Replace sensor: If the error disappears with a test sensor, install a new matching auxiliary sensor.
  • Board diagnosis: If Sn3 persists with a good sensor, the control board input may be defective and the board may require replacement by a technician.
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Repair Difficulty

Hard 4/5

Required Part

Auxiliary Temperature Sensor
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