Replaced the thermal regulator on a Pentair MasterTemp 250 pool heater. The customer reported inconsistent water temperatures, indicating a potential issue with the regulator. After shutting off the power and water supply, I removed the old thermal regulator, which was worn and no longer functioning properly. Installed a new OEM thermal regulator and ensured it was seated correctly. After reassembling the unit, I tested the heater to confirm it was maintaining the proper water temperature. The pool heater is now operating smoothly.
