![Pentair Stack Flue Sensor, 42002-0024S Pentair Stack Flue Sensor, 42002-0024S](https://cdn11.bigcommerce.com/s-whbac/images/stencil/300x300/products/2282/5295/290f4aaa-d840-41ca-8931-fb401718d4f7__27719.1669922498.jpg?c=2)
This Pentair Sta-Rite/Mastertemp Thermistor Temperature Sensor, 42001-0053S will normally give you and error code of E01 if this has to be changed. This is an easy change for a experienced pool or spa techican. Once installed the the pool heater will give you accurate temperaure readings.