Display shows Sn2, spa may shut down heater or display incorrect temperatures.

Safety first: Disconnect power at the GFCI breaker before working on sensors or heater components.

• 1. Identify sensor 2: On many Coleman packs, Sn2 refers to the high-limit or secondary temperature sensor mounted on the heater tube.
• 2. Check mounting: Ensure the sensor is firmly clamped or threaded into the heater tube and has not pulled out. Poor contact can cause false readings.
• 3. Inspect wiring: Follow the sensor cable back to the control board. Look for pinched or burned sections and verify the connector is fully seated.
• 4. Replace the sensor: If visual checks are good but Sn2 remains, replace the high-limit sensor with a compatible Coleman part. Quickly swap sensors to minimize water loss if it threads into the tube.
• 5. Board diagnosis: Persistent Sn2 with a new sensor suggests a control board fault. Have a technician test resistance values and replace the board if necessary.