Sunvic Diverter Valve 3 Port 22mm 8912291

The Sunvic SDV2291 is a three-port motorised diverter valve with 22mm connections. It sits in the pipework of a domestic heating system and directs the flow of heated water either to the hot water cylinder, to the radiator circuit, or to both, depending on demand from the programmer and cylinder thermostat. Sunvic motorised valves are built for reliability and a high specification, and this unit is supplied under part number 8912291.

• The valve head runs but the actuator does not move the spindle, so the system stays on heating or hot water regardless of the demand signal.
• Radiators heat up when only hot water is called for, or the cylinder fails to heat when heating is selected.
• The motorised head buzzes, clicks repeatedly or becomes hot without completing a full stroke.
• The valve body weeps from the spindle gland or from the port joints.
• The spindle is stiff or seized when turned by hand with the actuator removed.

• Confirm the existing valve is a three-port diverter with 22mm connections and that the replacement body matches the pipework layout.
• Check the part number on the old valve or its actuator head against 8912291 and the alternative number 4143605.
• Inspect the mating faces and olives on the existing pipework; a seal or washer set may be needed if the old joints are disturbed.
• Work on the wet side of a heating system should be carried out by a competent engineer, with the system drained or isolated as required.