Jacuzzi 1994-2002 Models Jacuzzi 2002-Present Models Gatsby Spas Retro Kits


Search Clear Creek Spas
Sensors Used In Electronic Jacuzzi Whirlpool Hot Tubs
JWB Sensor  Temperature and Overheat Sensors-Electronic
End connector is RED or WHITE
21-337 Complete Assembly (Temp and High Limit)
End connector is BLACK.
21-637  Temp Sensor 
21-638  High Limit 


Over Heat Sensor on JWB Vertical Heaters Only.




Sensor TEST and Install Help 


Sensors For The 2002+ "J Series" Spas

Sensors Education

Sensors: Spas use TWO sensors. The Temperature and the Overheat or High Limit sensor. 

Sensors basically change resistance values as the water heats or cools. The change in resistance tells the board the temperature of the water and the heater. If the sensor itself gives faulty or no resistance values, the spa will not operate or operates wrong. The board is smart enough that it will typically tell you by sensor error messages if the values are out of range by giving you a sensor error code on the topside. See Sensors Table

JWB installed their temperature sensor in the bottom of the filter cabinet. This sensor tells the board actual temp. If the topside reading on the board is off, then its usually this sensor (could be the board). If the board sees the water get too hot, it will attempt to cool the spa or shut down completely.

The OH or High Limit sensor has one purpose in life. It sits next to the heater and watches the heater closely. If the heater starts to overheat, the board sees the temp on the OH sensor and will shut the spa down. So if you get an OH error, either the heater IS overheating OR the sensor has failed.

FYI: Sensors can be sporatic in the readings. If you see the topside change temp readouts in large increments, likely the Temp sensor needs replacing..


Click Geeks  

Click Tutor Icon  

Sensor TEST and Install Help



Copyright 2021 Clear Creek Spas
All Rights Reserved