Sunvic Actuator SZ2201 4082201

The Sunvic SZ2201 is an actuator: the electrically driven head that sits on a valve body and moves the valve open or closed in response to a demand from the heating controls. It is manufactured by Sunvic and supplied under part number 4082201. The actuator is the moving half of the assembly — the valve body stays in the pipework while the head is removed and replaced.

• The valve no longer responds to a call for heat, so the circuit stays cold or stays permanently open.
• The actuator motor runs continuously, buzzes, or is audibly straining without moving the valve spindle.
• The valve sticks in one position, giving heating or hot water that cannot be switched off at the controls.
• The head is hot to the touch, smells of burnt insulation, or has visible scorching around the motor housing.
• The manual lever moves without any resistance or does not return, indicating a failed return spring or drive mechanism.

• Confirm the part number on the existing actuator head matches 4082201 or the SZ2201 model reference.
• Check the valve body it is being fitted to, as the head must match the body it drives.
• Note the alternative number 4143460 in case it appears on the old component or the paperwork.
• Inspect the sealing washer or O-ring between head and body and replace it if it is perished or flattened.