The Honeywell V4073A is a spring-return valve. Port A or port B can be closed by a rubber ball, though never both at the same time. The rubber ball is moved between ports A and B by an actuator shaft or spindle which is driven by the powerhead. The inlet port AB can never be closed; the ball only moves between port A and port B. This can cause the valve spindle to seize. It often becomes stiff to turn at first and the valve may give intermittent problems. Eventually, the spindle may become so stiff that the valve motor cannot turn it at all. V4043C1156 is a 2 port, ½” BSP Female threaded, 3-wire, normally-closed zone valve but has no end switch Inside a Honeywell V4073A 3-port motorised valve showing the rubber ball which closes one or other port, never both. The Honeywell valves have a D-shaped top to the spindle but you can also use a spanner on this. If you do this, you must use very little force as it is very easy to shear a spindle or damage the valve internally.

Replacing a failed Synchron motor in a Honeywell motorised valve is quite straightforward, assuming you know how to work with mains electricity safely. Make sure you read the whole process through before starting! A normally-open valve is open when no power is being applied to it and needs electrical power to drive it closed. If it’s the other way round, and the 2-port valve controlling the hot water circuit is failing, it may be less obvious. The heating circuit valve may be open for long periods telling the boiler to fire. If the hot water valve is partially open, you may not run out of hot water. port motorised valves have three plumbing connections, one for the flow in and two outputs. Our 3 port valves come in 22mm and 28mm sizes, with the most popular motorised valve being the Honeywell Home V4073A Mid-Position Valve – 3 Port 22mm valve. A 3 Port Mid-position Rotary Shoe Valve 22 mm from Danfoss is also available in this selection. The wires to disconnect are the two wires which run from the motor. On earlier motorised valves, these were both joined to other wires using metal crimps encased in plastic. On more recent valves, one wire is joined with a crimp and the other is wired directly to the electrical components of the valve.When all electrical power to the heating controls is switched off, the spring pulls the ball across to close port A, leaving port B open. This is the relaxed state or de-energised state of the valve. It is also sometimes called the Normal state.

Both of these genuine SYNCHRON motors work in Honeywell motorised valves. The motors SYNCHRON make specifically for Honeywell come with two blue wires On modern Honeywell valves, if the powerhead fails it can be removed from the valve body without draining down. However,be warned!With very old Honeywell motorised valves the powerhead could not be removed without draining the water first. The Honeywell V4073A 3-port valve has five wires. These are blue, green/yellow, white, grey and orange. Note that the grey and orange wires are used differently from the grey and orange wires of the 2-port valve! If Hot Water is then satisfied (either by the programmer or cylinder stat), the grey wire is energised. As there is still a demand for Heating, the valve will motor to the Heating Only position (port A open; port B closed) and switch a 230V supply onto the orange wire, to power the boiler.

When the programmer and stat send a Live feed to the 2-port motorised brown wire, the motor drives the valve open to allow water to pass. When the valve is fully open, the end switch closes, allowing electrical current to pass from the grey wire to the orange wire and from there to the boiler Switched Live. Unless the boiler thermostat is already up to temperature, the boiler will now fire.