Vaillant 011289 Diverter valve

The Vaillant 011289 is a diverter valve manufactured by Vaillant for use in its domestic heating appliances. It sits in the hydraulic circuit and switches the flow of water between the central heating loop and the domestic hot water plate heat exchanger, so the appliance sends heat to the right place at the right time. It is classed as a diverter and motorised valve spare.

• Domestic hot water runs cold or only lukewarm while the heating circuit works normally
• Radiators heat up when only hot water is demanded, or hot water is produced when only heating is called for
• The valve head does not move when the appliance switches between heating and hot water modes
• Intermittent or repeated fault codes relating to the diverter valve or water flow on the appliance display
• Water weeping from the valve body or around the spindle area

• Check the model and GC number on the appliance data badge against the compatibility information for this part
• Confirm the part number on the existing valve matches 011289 before removal
• Inspect the sealing washers and O-rings on the valve body and replace them if they are compressed or perished
• Work on the hydraulic circuit involves draining and refilling the appliance, so isolate the water and power supplies first