I have Balboa control and heating on my 6 year old hot tub. It is the system with two sensor going into the heating unit and no other sensors. I recently got the "Sn" code and the spa will not turn on. My owners manual confirms that the spa will be disabled if the Sn code displays. Since it was so cold, and my spa was in sleep mode, I opened the panel and made sure there was water ( not ice) in the heating element. (I cracked open the connections to make sure water was coming out and used a blow dryer on the heating element. then allowed it to sit with the panel off in yesterday's 45 degree temperature for a few hours). It still does not start and the SN code comes on. I see from Spa Depot that the sensors are both the same and if I replace one I should replace both. I have no experience with troubleshooting or fixing spas. However, if it most likely bad sensors, I would rather just replace them than spend a ton of money calling a service person. Does anyone have any suggestions?
Thanks for any input.