Honeywell Motorised Zone Valve 28mm 3 Port HONEYWELLV4073A1088

The Honeywell V4073A1088 is a 3-port motorised zone valve built for domestic wet central heating systems. It sits on the pipework between the heat source and the two circuits it serves, opening and closing under the control of the programmer, room thermostat and cylinder thermostat so that heat is sent to the radiators, the hot water cylinder, or both. The valve body takes 28mm pipework and is supplied as a complete unit with the actuator head fitted.

• Heating or hot water fails to come on when only that circuit is called for, even though the programmer and thermostats are working.
• The actuator head hums or buzzes but the spindle does not turn, so the valve stays in one position.
• The manual lever moves freely with no resistance, or does not spring back when released.
• The system stays on heating or hot water permanently, regardless of the thermostat setting.
• Water weeps from the valve body, spindle gland or compression nuts.

• Confirm the pipework is 28mm and that the existing valve is a 3-port configuration, not a 2-port.
• Read the part number from the actuator head or body of the old valve and match it against the number listed here.
• Check whether the valve body is being reused; if so, a replacement ball, plate and seal kit may be needed separately.
• Isolate the heating circuit and drain down before removing the old valve, and check the system for correct inhibitor concentration on refill.
• This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.