Review on 💧 Premium Balboa Water Group Sensor Assembly with Temperature and High-Limit Sensors: A Perfect Fit for Efficient Water Control by Andrew Agarwal

I ordered this build after realizing the one on my 16-20 year old Balboa controller spa was defective. There was an Sn1 error on the top plate that indicated an upper limit sensor - a smaller one, although the assembly was replaced in due course. After removing the exterior panels and the hot tub controls, the replacement took less than 10 minutes. My hot tub no longer displays the error and returns to full temperature. Hooray! The part arrived fairly quickly which was a big plus for ordering here, although it can be had for a few bucks less elsewhere if shipping is included. I wanted my spa up and running as soon as possible, not a week. However, I strongly recommend that customers only purchase this product after full confirmation of the failure of one or both sensors. How you do that? You will need a multimeter (preferably a good quality digital one) and test leads small enough to fit in the small connector (front or back) of the assembly. Alternatively, you can use something like a paper clip to insert it into the connector and then examine it directly instead of the connector. Wait for the spa to stop working (e.g. shows error Sn1 like mine did) then turn it off with the main switch. (I repeat: TURN THE SPA OFF.) Disconnect the connector from the board and check each pair of connections for the resistance setting (kΩ if your DMM doesn't support autoranging); Just look at the incoming wires to see which wires go to which sensor. The resistances of the sensors should be within 1-2 kΩ, maybe within 25-30 kΩ plus or minus depending on the temperature. If there is a big difference, one of them has failed. You may need to wiggle the wires at the base of the sensor, or heat and cool the sensors (alternate between ice water and very warm water). Don't think that one read will tell you the whole story. In my case, the smaller high-limit sensor looked fine at first, but after I warmed it up a bit (which is why I say run the spa until it indicates a fault or misbehavior), it reads something tiny, about 7k ohms by comparison to 25kOhm at the temperature sensor (large). The resistance drops as it heats up, so the controller assumes that the heater temperature has risen sharply and the water has not changed. So the controller shuts everything down so as not to burn out the heater or maybe even start a fire. These sensors are thermistors - variable resistors that change resistance depending on temperature. The information I can find shows that while reliable, they still have a failure rate 3 times higher than other passive components in the system. Obviously, the heating and cooling stresses the materials inside. However, do not resort to spare parts. Know a part is bad before you spend money to replace it.