Replacement thermal regulator compatible with Pentair MasterTemp 125, part number 474989. This directfit replacement restores accurate temperature control and reliable heater operation without modifying the original assembly. Key benefits Restores temperature regulation: Replaces a failing or intermittent thermal regulator to bring heater controls back to normal function. Direct fit and easy installation: Designed to match the original part form factor and mounting points for straightforward replacement with existing wiring harness. Reliable operation: Built to provide consistent thermal sensing and switching so the heater cycles correctly and runs as expected. Reduces downtime: Fast replacement minimizes time out of service compared to extended troubleshooting or unit replacement. Important attributes Function: Thermal regulator for monitoring and controlling heater temperature. Compatibility: Compatible with MasterTemp 125 models that use part number 474989. Size and fit: Direct replacement size and mounting configuration to match the original regulator for plug and play installation. Material and durability: Constructed from durable components intended for long term use in heater environments. Performance: Restores accurate temperature control and reliable on off cycling of the heating system. Use scenarios a failed thermal regulator during a field to restore a pool heater to working condition. Perform scheduled maintenance and swap the regulator to prevent intermittent temperature control issues. Service a MasterTemp 125 after diagnostics indicate temperature sensor or regulator faults to the unit to normal operation. Notes Confirm your heater model and part number 474989 before to ensure compatibility. Intended as a replacement component for the specified MasterTemp 125 models.