420020007S Control Board Kit for Pool and Spa Heaters Key benefits Restores full control of heater functions by replacing a failing control board. Fixes temperature adjustment failures and unresponsive or hard buttons. Allows precise temperature setting and easy selection between spa and pool modes to improve heating consistency and responsiveness. Built for reliability with upgraded components that reduce the risk of electrical faults and extend service life. Compatibility Designed for NA and LP series pool and spa heater electrical systems. Compatible control board replacements include: MasterTemp 200, 250, 300, 400, 400HD. Also compatible with StaRite MaxETherm models: SR200NA, SR333NA, SE400NA, SR200HD, SR333HD, SR400HD. What makes this board stand out Upgraded construction: uses FR2 copper foil laminate for improved electrical insulation and conductivity. Enhanced modules: improved optocoupler module and regulated power module provide builtin protection against overheat, overvoltage, and short circuit conditions. Additional protection: SR waterproof coating offers wear and corrosion resistance, moisture protection, and reduced risk of leakage for longerlasting reliability. Function and performance Controls temperature settings and circuit functions used to switch between spa and pool heating modes. Addresses common control board issues such as temperature reading errors and hard or nonresponsive membrane pad buttons. Engineered to maintain stable electrical performance under normal heater operating conditions. Quick installation overview Power down the heater before starting. Open the heater access panel and disconnect the membrane pad and wire connectors from the old circuit board. Remove the four mounting screws and extract the old board. Install and secure the board, then reconnect the membrane pad, ribbon cable, and wire connectors. Power up and verify proper operation of temperature controls and mode selection. Material and specifications Kit model: 420020007S control board kit. Includes board assembly designated 461105 built on FR2 copper foil laminate. Protective SR waterproof coating applied to the board surface. Contains upgraded optocoupler and regulated power modules for improved electrical protection. Practical applications and use scenarios a failed control board in a backyard pool heater after the display or buttons stop responding, restoring normal temperature control and scheduling. Swap in the kit during routine heater maintenance when signs of corrosion or moisture damage are found on the original circuit board. Upgrade a unit showing intermittent heating or fault codes related to power regulation to reduce downtime and improve heating reliability. What to expect Directfit replacement for listed compatible models to restore full control functionality. Improved resistance to moisture and electrical stress compared to older boards. Straightforward installation for qualified technicians or experienced homeowners familiar with heater electrical service. Package contents 420020007S control board kit including 461105 board assembly and associated connectors as required for direct replacement. Note Ensure power is disconnected before performing any work. If unsure about installation, consult a qualified technician.