Product: 420020007S Control Board Kit (includes 420020007S control board and 420020029Z switch membrane pad) What's included 1 × 420020007S (461105) control board 1 × 420020029Z (472610Z) switch membrane pad Why you need this kit Restores heater operation when the unit won't start, the display is unlit, or the pool water heats slowly. Replaces the exact OEMstyle control board and keypad film for a direct fit and straightforward swap. Upgrades reliability with improved components to reduce future downtime and protect the heater electronics. Key benefits Direct compatibility: Designed for Pentair MasterTemp NA and LP electrical systems and fits MasterTemp 200, 250, 300, 400, and 400HD control boards, as well as StaRite MaxETherm SR200NA, SR333NA, SE400NA, SR200HD, SR333HD, and SR400HD control boards. Improved protection: Built with an enhanced optocoupler and regulated power modules that provide overheat, overvoltage, and shortcircuit protection. Better performance: Faster output control and more efficient operation help maintain consistent temperature control and improve heating responsiveness. Quality construction: Made from FR2 copperclad plate with a main control chip for stable, durable electrical performance. Simple safetyfirst installation steps 1. Turn off all power to the heater. 2. Open the of the heater and remove the four screws securing the circuit board. 3. Remove the existing 472610Z switch membrane pad from the old board. 4. Unplug the wire connector from the old board and install the 420020007S board and 420020029Z membrane pad. 5. Reassemble and restore power only after completing installation. Problems this kit addresses Heater won't start or display is dark Slow or inconsistent water heating Unresponsive keypad or control buttons Intermittent faults due to aging control electronics Typical use scenarios a failed control board on a MasterTemp 250 after the display stops powering up, restoring full control and display function. Swap in the upgraded board on a StaRite SR333NA to add overvoltage and shortcircuit protection after a lightningrelated surge damaged the original electronics. a worn switch membrane pad on an inservice MasterTemp 400 to fix sticky or unresponsive keypad buttons and regain reliable temperature adjustments. Compatibility summary Pentair MasterTemp NA and LP series electrical systems MasterTemp control boards: 200, 250, 300, 400, 400HD StaRite MaxETherm control boards: SR200NA, SR333NA, SE400NA, SR200HD, SR333HD, SR400HD Materials and performance Board material: FR2 copperclad plate Components: main control chip, improved optocoupler, regulated power modules Protection: overheat, overvoltage, shortcircuit Result: faster output control, more efficient heater operation, consistent temperature control If your heater shows startup failures, an unlit display, slow heating, or unresponsive controls, this 420020007S control board kit provides a direct replacement and improved protection to restore reliable, efficient operation.