Baxi

The Baxi three-way valve SX0607250 is a diverter valve that controls the flow of heated water between the central heating circuit and the domestic hot water (DHW) circuit. When a hot water tap is opened, the valve shifts to direct the boiler’s output to the DHW heat exchanger; when the tap closes, it returns to the heating position. This component is electromechanical, typically actuated by a motor and controlled by the boiler’s circuit board. Over time, the valve can stick or fail due to debris or wear, leading to loss of hot water or heating. Replacing it with the genuine SX0607250 ensures correct flow characteristics and compatibility with Baxi boiler models that use this part.

The safety valve SX9950610 is a pressure relief device designed to open automatically if the boiler’s water pressure exceeds 7 bar. This is a critical safety feature because excessive pressure can damage the heat exchanger, pipework, or even cause the boiler casing to rupture. The valve is typically set to open at 7 bar, which is above the normal operating pressure of a sealed heating system (usually 1-2 bar) but below the pressure that would cause structural failure. If the valve is faulty or missing, the boiler could be at risk of overpressure events. Regular testing and replacement of this valve are part of standard boiler maintenance to ensure the system remains safe.

The ignition electrode SX8422580 generates a high-voltage spark that ignites the gas-air mixture in the boiler’s burner. When the boiler receives a call for heat, the control board sends a signal to the electrode, which produces a spark across its gap. This spark ignites the gas, and once the flame is established, a flame sensing electrode (often part of the same assembly) detects the presence of the flame and signals the control board to keep the gas valve open. If the electrode is worn, cracked, or covered in carbon deposits, it may fail to spark or sense the flame, causing the boiler to lock out. Replacing the electrode with the genuine SX8422580 ensures proper spark gap and insulation, which are critical for reliable ignition.

The Baxi fuse SX9950580 is a 2-amp thermal fuse used in the boiler’s electrical circuit to protect against overcurrent or over-temperature conditions. This fuse is designed to blow if the current exceeds 2 amps, which could indicate a short circuit or component failure, or if the temperature around the fuse exceeds its rated threshold, which could indicate overheating. When the fuse blows, it interrupts the electrical supply to the boiler, preventing further damage or potential fire hazard. The bag of 10 provides a convenient supply for maintenance teams that service multiple boilers. Always replace a blown fuse with the same rating (2A) to maintain the protection level.

The micro switch valve 3V SX5641800 is a small electrical switch that is mechanically actuated by the position of the three-way valve. It provides feedback to the boiler’s control board about whether the valve is in the heating position, hot water position, or mid-position. This information is used to sequence the pump and burner operation correctly. If the micro switch fails, the boiler may not know the valve’s position, leading to incorrect operation, such as heating when hot water is demanded or vice versa. The switch is a common failure point due to mechanical wear or electrical contact degradation. Replacing it with the genuine SX5641800 ensures accurate switching and reliable boiler operation.

The circuit board SX5657840 has been superseded by the part number JJJ005678220, meaning that the manufacturer has updated the board design or part numbering system. Supersession is common in the heating industry as manufacturers improve components, address obsolescence, or consolidate part numbers. The new part JJJ005678220 is designed to be a direct replacement for the old SX5657840, maintaining the same electrical connections and functionality. When ordering, it is important to use the current part number to ensure you receive the latest version. 3G Electric stocks the superseded part to ensure you get a compatible and up-to-date component for your Baxi boiler.