{"product_id":"thermistor","title":"Sta-Rite Thermistor for Max-E-Therm and MasterTemp Heater Electrical System","description":"\u003cp\u003eSta-Rite 42001-0053S is the replacement thermistor for the Max-E-Therm SR-200, SR-333 and SR-400 heaters. The same sensor is part of the MasterTemp heater electrical system.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat it does\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eThe thermistor is the heater control board eyes on water temperature. Its resistance changes with temperature, the board reads that, and everything downstream follows: what the display shows, when the burner fires, when the heater satisfies the setpoint and shuts down.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhen it is the problem\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eA drifting or failed thermistor makes the heater behave in ways that look like other faults. Temperatures that read nothing like the pool, a heater that will not fire even though the pool is cold, or short cycling near setpoint all point at the sensor. It is an inexpensive part to change and a common one to find at fault.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eFitting\u003c\/strong\u003e\u003c\/p\u003e\u003cp\u003eIt is a direct OEM replacement, so it goes back into the same location on the same wiring. Kill power at the breaker before opening the heater.\u003c\/p\u003e","brand":"Sta-Rite","offers":[{"title":"Default Title","offer_id":48625790025940,"sku":"STA-151-6254","price":93.78,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0801\/9568\/2516\/files\/default_a27c6fbf-5ba5-464c-96d7-4cc536955b40.jpg?v=1788700123","url":"https:\/\/www.activepoolsupply.com\/products\/thermistor","provider":"Active Pool Supply","version":"1.0","type":"link"}