Glow-worm Main Printed Circuit Board BMU GLOWWORM0020023825

The Glow-worm 0020023825 is the main printed circuit board, also referred to as the BMU board, used in Flexicom and Ultracom appliances. It is the control board that runs the boiler's operating sequence, managing ignition, fan and pump output, temperature sensing and the safety interlocks that sit behind them. It is supplied as a service spare for replacement when the original board has failed.

• The boiler fails to fire and goes to lockout with no obvious gas, water or pressure fault present.
• The display is blank, flickers or shows erratic readings when the appliance is powered.
• The fan, pump or other driven components do not run despite a call for heat.
• Fault codes appear repeatedly, clear after a power cycle and then return.
• Heating, hot water or both become intermittent or stop altogether with no mechanical cause found.

• Read the part number from the board currently fitted and confirm it matches 0020023825.
• Note the appliance GC number and serial number from the data badge so the correct variant is identified.
• Inspect the board connectors and wiring loom for heat damage or corrosion; a replacement board will not correct a loom fault.