Replacement Synchronous Motor for motorised valves ACL Honeywell Landis Gye Satchwell Sopec Tower DIY Replacement 2-Port 3-Port Valve Failure

Product Information

V4043H1106 is a 2 port, 28mm compression, 6-wire, normally-closed zone valve with an auxiliary end switch The blue wire is the Neutral, N. The green/yellow wire is the Earth wire, E. The white wire is connected to the wire from the room thermostat which calls for heating (radiators or underfloor). The grey wire is used to drive the valve to the Water Off position, in which only the heating port A is open; it closes port B. The orange wire provides a Switched Live (Switched Line) feed to run the boiler and pump. Honeywell V4043H1056 22mm 2-port zone valves have five wires: green/yellow is Earth, blue is Neutral, brown is Live (or Line) to the motor, grey and orange are connected to the end switch and form part of a separate circuit. A failed motor will prevent the motorised valve from opening but it is not the only cause of a valve failing to open correctly. After years of use, the O rings sealing the valve spindle (or actuator shaft) can fail. When this happens, central heating water will seep past and will corrode the metals.

Motorised valves are often fitted in tight spaces with limited visibility so note the orientation of the powerhead. Sometimes a powerhead is able to drive the valve only part way open but not far enough for the auxiliary circuit end switch to close. This valve will then not be able to tell the boiler to fire.When Heating is also called for, the white wire is energised and the valve will motor to, and stop in, a mid-position. Power for the boiler is still supplied directly from the cylinder thermostat. The orange valve wire may have a potential of 230V but this is coming from the cylinder stat (to which the orange wire is also connected) and not from the circuitry of the valve. If, for example, the heating valve is failing in this way, you will get heat round the radiators while the cylinder hot water is being heated too. When the cylinder is up to temperature, the hot water motorised valve closes and no longer tells the boiler to fire, so the heating now stops too. If the powerhead (actuator) can be safely removed from the valve body (see warning above about pre-1985 Honeywell valves) you can try to turn the spindle. You may need a tool unless you have strong fingers. You must also isolate the electrical supply before removing a Honeywell motorised valve powerhead. 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!

Honeywell V4044C1288 22mm 3-port diverter valve. This valve is not a mid-position valve. It opens either Port A or Port B (usually heating and hot water). Apart from the few moments when it is switching between ports, Port A and Port B are not open together. Note that it is a 3-wire valve, not a 5-wire valve

Honeywell V4073A1039 22mm 3-port mid-position diverter valve. These are 5-wire valves. When used with other Honeywell controls the setup is know as Y Plan It may be easier to have the valve set in the manually open position using the manual lever. (See Honeywell Motorised Valve Manual Lever, below.) There are lots of poor quality synchronous motors out there. If the motor cap says “Synchronous” rather than “SYNCHRON ®” it may cost less than half but you’ll probably be changing it again before long! We find it is normally about 2.1kΩ (2100 ohms) if the motor is cold and up to 2.4kΩ (2400 ohms) if the motor is quite warm. I think that a reading anywhere between 2.0kΩ (2000 ohms) and 2.5kΩ (2500 ohms) suggests that the motor windings are probably OK. If the reading is many times higher than that, or it is open circuit, the motor has failed.

When using a 3-port valve, the control system may be known as a Sundial Y Plan system or a Honeywell Y Plan system. Where two 2-port motorised valves are fitted (one for the heating circuit and one for the hot water cylinder circuit) the fault may be disguised. Even though one valve only partly opens itself and is unable to fire the boiler, the valve on the other circuit can open fully and fire the boiler. The pump then pushes heated boiler water through both the open valve and the partially open valve. The auxiliary circuit allows several 2-port motorised valves to be used to control separate zones without interacting electrically. Otherwise, if several zone valves were used without auxiliary circuits, and all were connected to the same pump so that the Live wire that opened each valve also fed the pump Live, there would be problems.Honeywell make a large range of motorised valves used in domestic central heating systems. The most common by far are the 22mm 3-port, 5-wire, mid-position valve and the 22mm 2-port, 5-wire, zone valve. These 22mm valves (3-port V4073A1039 and 2-port V4043H1056) are used in smaller and medium sized properties. 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. 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. Starting with the controls set for Heating Only, hold the lever tight against the right side of the slot. Now get someone to select Hot Water too, so you get Heating and Hot Water together. You may need to turn the cylinder stat up to make it call. As soon as Hot Water is also called, you will hearthe valve start to unwind under the force of the spring, then you will feel the lever “bump” your finger. Synchron valve motors can remain energised and hot for many hours a day, all through the winter. They may eventually fail. A failed Synchron valve motor will prevent a 2-port motorised valve from working. The valve won’t be driven open and the end switch will not be made (connected) so power will not be sent on to the boiler or pump.

V4043H1007 is a 2 port, ¾” BSP Female threaded, 5-wire, normally-closed zone valve with an auxiliary end switch 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. When a V4073A mid-position valve is set up in a Y-Plan configuration and Hot Water is called for, power to the boiler is provided directly from the cylinder thermostat. The valve is not energised. The commonest fault with Honeywell motorised valves is motor failure. Honeywell valve motor fault? Testing a Synchron valve motor This can be difficult to feel for at first. It is most obvious when the valve has been in the Heating Only position and reverts to the mid-position.

The Y Plan and S Plan names are more commonly used when other Honeywell controls are also used (programmer, room thermostat, cylinder thermostat and wiring centre).