{"product_id":"pentairmastertemp125thermalregulator474989pen474989","title":"Pentair MasterTemp 125 Thermal Regulator | 474989","description":"\u003cdiv\u003e\n  \u003ch2\u003ePentair Thermal Regulator for MasterTemp® 125 Heater Water System | 474989\u003c\/h2\u003e\n\n  \u003cp\u003e\n    The Pentair \u003cstrong\u003e474989\u003c\/strong\u003e Thermal Regulator is an OEM replacement temperature-regulating valve used in the\n    \u003cstrong\u003eMasterTemp 125\u003c\/strong\u003e heater water system. It helps the heater maintain proper internal water temperature and\n    flow characteristics during operation, supporting stable heating performance and helping protect internal components.\n  \u003c\/p\u003e\n\n  \u003ch3\u003eKey Features\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eOEM thermal regulator:\u003c\/strong\u003e designed to match the original part specification for MasterTemp 125 water system assemblies.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eHelps stabilize heater operation:\u003c\/strong\u003e supports consistent water temperature control inside the heater.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eDirect replacement:\u003c\/strong\u003e restores proper performance when the original regulator is stuck, worn, or damaged.\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFor MasterTemp 125 models:\u003c\/strong\u003e intended for the 125,000 BTU MasterTemp heater platform (verify by parts diagram).\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch3\u003eCompatibility\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eFits:\u003c\/strong\u003e Pentair \u003cstrong\u003eMasterTemp 125\u003c\/strong\u003e pool\/spa heaters (water system section) where part \u003cstrong\u003e474989\u003c\/strong\u003e is specified.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch3\u003eCommon Symptoms of a Failed Thermal Regulator\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003eHeater performance becomes inconsistent (unstable heating or frequent cycling)\u003c\/li\u003e\n    \u003cli\u003eInternal bypass\/regulation issues due to sticking or weakened regulator mechanism\u003c\/li\u003e\n    \u003cli\u003eService diagnosis points to the heater water system regulator as the root cause\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch3\u003eInstallation Notes\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003eTurn off power to the heater and pump and allow the heater to cool before servicing.\u003c\/li\u003e\n    \u003cli\u003eRelieve system pressure and drain water from the heater as needed before opening the water system.\u003c\/li\u003e\n    \u003cli\u003eInspect mating surfaces and internal water components while the heater is open.\u003c\/li\u003e\n    \u003cli\u003eReassemble carefully and check for leaks after restart.\u003c\/li\u003e\n    \u003cli\u003eHeater service is best performed by a qualified pool professional.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch3\u003eSpecifications\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Pentair\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e 474989\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003ePart Type:\u003c\/strong\u003e Thermal regulator (heater water system component)\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eApplication:\u003c\/strong\u003e MasterTemp 125 pool\/spa heater\u003c\/li\u003e\n    \u003cli\u003e\n\u003cstrong\u003eQuantity:\u003c\/strong\u003e Sold individually\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch3\u003eRelated Products\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/aquapoolsupply.com\/pages\/search-results-page?q=474989\"\u003eSearch Aqua Pool Supply for 474989\u003c\/a\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/aquapoolsupply.com\/pages\/search-results-page?q=MasterTemp%20125%20parts\"\u003ePentair MasterTemp 125 replacement parts\u003c\/a\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/aquapoolsupply.com\/pages\/search-results-page?q=77707-0016\"\u003eMasterTemp 125 Manifold Kit (77707-0016)\u003c\/a\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/aquapoolsupply.com\/pages\/search-results-page?q=474974\"\u003eMasterTemp 125 Union 1-1\/2\" Kit (474974)\u003c\/a\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/aquapoolsupply.com\/pages\/search-results-page?q=42001-0060S\"\u003eMasterTemp Water Pressure Switch (42001-0060S)\u003c\/a\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/aquapoolsupply.com\/pages\/search-results-page?q=473715Z\"\u003eMasterTemp Pressure Relief Valve (473715Z)\u003c\/a\u003e\u003c\/li\u003e\n    \u003cli\u003e\u003ca href=\"https:\/\/aquapoolsupply.com\/pages\/search-results-page?q=heater%20gasket\"\u003ePool heater gaskets \u0026amp; seals\u003c\/a\u003e\u003c\/li\u003e\n  \u003c\/ul\u003e\n\n  \u003ch3\u003eMaintenance Tips\u003c\/h3\u003e\n  \u003cul\u003e\n    \u003cli\u003eMaintain proper water balance to reduce scale buildup that can affect heater water system components.\u003c\/li\u003e\n    \u003cli\u003eKeep good circulation (clean filter, clean pump basket) to support stable heater performance.\u003c\/li\u003e\n    \u003cli\u003eIf you service the heater water system, inspect related seals and replace worn gaskets to prevent leaks.\u003c\/li\u003e\n    \u003cli\u003eAddress low flow conditions early—many heater issues are caused by restricted circulation.\u003c\/li\u003e\n  \u003c\/ul\u003e\n\u003c\/div\u003e\n","brand":"Pentair","offers":[{"title":"Default Title","offer_id":46797895467183,"sku":"474989","price":59.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0734\/6415\/2239\/files\/pentair-mastertemp-125-thermal-regulator-474989-heater-parts-2364023.jpg?v=1777068938","url":"https:\/\/freshized.com\/products\/pentairmastertemp125thermalregulator474989pen474989","provider":"Freshized","version":"1.0","type":"link"}