My pool heater has a problem. It heats the spa water fine to about 95 degrees, then the heater stops heating and cycles on then off for a few minutes at a time until it reaches 102 (set limit). This takes much longer than usual to heat up the spa with this happening. The water also does not feel like it is 102 when it says it is?? The SERVICE HEATER light and the HLS led (under the control panel) turn ON when the heater shuts off, then resets themselves after a few minutes then the heater turns on again.
I am thinking the high temp level sensor may be bad. I removed it(chased the wiring of the HLS led to that sensor), inspected visually, and put it back in. The markings on it are SA TOD 441631 316109 L135F. Is this a common part that fails.