Worcester Bosch Control Unit ACU-L 8737604617

The Worcester Bosch 8737604617 is a control unit of the ACU-L type, supplied together with a code plug numbered 25137. It forms part of the appliance's control box assembly and governs the boiler's operating sequence, receiving inputs from the sensors and the user controls.

The unit is used on Worcester Bosch Greenstar 2000 Combi appliances, including the GR2300iW 25 C LPG variants. The code plug carries the appliance configuration data, so the control unit and plug are matched to the model they are fitted to.

• The appliance does not respond when there is a call for heating or hot water.
• The control unit shows no display or no power at the user interface.
• Fault codes appear on the appliance and cannot be cleared.
• The boiler runs erratically, or locks out shortly after ignition.
• The board shows visible heat damage, corrosion or moisture ingress.

• Check the GC number and model on the appliance data badge against the compatibility list above, as the code plug is model specific.
• Confirm the code plug number on your existing control unit is 25137 before ordering the replacement.
• Note the alternative part number 2249515 when cross-referencing older documentation.
• This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.