Honeywell Motorised Valve 3 Port 22mm Compression V4073A1039/U

The Honeywell Home V4073A1039/U is a three-port motorised valve with a spring-return actuator, used to divert flow between heating and hot water circuits on a pumped central heating system. It is a mid-position valve, so the actuator can hold the shoe in an intermediate position to serve both circuits at once. The body is brass with 22mm compression connections and the head is wired into the system controls on a five-wire installation.

• The valve head runs but the shoe does not move, so heating or hot water stays on or off regardless of the programmer.
• The manual lever has lost its spring resistance or will not latch, indicating a failed return spring or seized spindle.
• The actuator motor buzzes or hums continuously without driving the valve through its full travel.
• Water weeps from the valve body, spindle gland or compression nuts.
• The system reaches temperature on one circuit only, with the other staying cold when it should be calling.

• Confirm the valve body and actuator head match the part number on the existing unit before ordering.
• Check the system wiring arrangement, as the five-wire connection must match the controls already installed.
• Inspect the compression nuts and olives on the existing pipework and replace them if they are distorted or corroded.
• Fitting must be carried out by a qualified installer.