420020007S Control Board Kit — Upgraded replacement for Pentair MasterTemp and Sta‑Rite Max‑E‑Therm heaters Key benefits — why you need this kit Fixes common heater failures: resolves nostart conditions, unlit displays, and slow water heating. Improves reliability: , secure connectors eliminate looseconnection problems that can cause intermittent faults. Lowers operating cost: faster, more efficient heater control reduces pump run time and energy use. Protects your heater: builtin safeguards reduce risk from overheating, overvoltage, and short circuits. What makes it better Upgraded connectors for a secure, vibrationresistant connection. Upgraded solidstate capacitors and power chips plus precision soldering for longer life and consistent performance. Improved optocoupler module and regulated power module for faster output control and stable operation. Protection features include overheat, overvoltage, and shortcircuit protection. FR2 copper foil laminate board construction and robust SR waterproof coating for improved insulation, moisture resistance, and protection against leakage. Compatibility Compatible with all Pentair MasterTemp NA and LP series pool and spa heater electrical systems. Directly compatible with MasterTemp control boards: 200, 250, 300, 400, 400HD. Also compatible with Sta‑Rite Max‑E‑Therm control boards: SR200NA, SR333NA, SE400NA, SR200HD, SR333HD, SR400HD. Function and expected results Restores reliable control and faster heatup times for MasterTemp heaters. Reduces unnecessary pump operation by improving heater responsiveness and efficiency. Addresses symptoms such as nonstarting heaters, blank displays, and slow water temperature rise. Practical use scenarios a failed 420020007S board in a MasterTemp 250 where the heater will not start and the control display is dark. Upgrade an older MasterTemp unit before peak season to improve response time and reduce pump runtime. Install in a pool heater located in a humid or coastal environment to benefit from improved moisture resistance and reduced leakage risk. Materials and quality FR2 copper foil laminate PCB for stable electrical performance. Solidstate capacitors and precision soldering for durability. SR waterproof coating for added protection in wet environments. Notes This is a replacement control board kit compatible with the listed Pentair and Sta‑Rite models (420020007S). Power off and follow safety procedures during installation. Professional installation is recommended if you are not qualified to service pool heater electrical systems.