1. Water temperature is below 36F or above 110F
2. If the two thermistors are more than 2 degrees apart, the SNS code will appear.
3. Loose or corroded connection at P1.
4. If the sensor is not mounted all the way into the JACO fitting on the header, it may give a false reading.
Temperature sensor is part 6-C on top left of page 50. It's in the heat exchanger, see page 25.
I have the RayPak 2100 Digital NGas (P-R405A-EN) and it came with the house 11 years ago.....and was probably 5 years old when we got it. So 16 years I guess, but now it has lost its spark, I think . No ignition and it says SPK 22. So now I'm wondering if the life of the heater is at its end...
I don't know age. Previous owner gave me some incorrect data regarding the pool situation.
I used leaf blower and cleaned out 5" of bamboo leaves on the grates and then removed the metal cover around the controller. I cleaned that area and it immediately "clicked' and started right up. I noticed a bit of moisture so I suspect it was related.