Seized motorised valve spindle in an old Satchwell Sunvic 2-port motorised valve. The water leakage has caused white oxides to form round the brass spindle, making it too stiff to turn The V4043 series of 2 port Motorised Valves has a wide range of flow control applications in domestic and light commercial central heating systems. The V4043H normally closed models have end switches for electrical control of pump and/or boiler. V4043H1080 is a 2 port, 1” BSP Female threaded, 6-wire, normally-closed zone valve with an auxiliary end switch Honeywell say that the manual lever located on the end of the powerhead is not a position indicator and should be used used for filling the system and for draining down only. It will make it easier when re-fitting it (just remember which end the flex was connected or take a picture on your phone). The powerhead can only fit one way round onto the valve body but if space is tight that might not be obvious.

Motorised Valves | Honeywell | Zone Valves | Toolstation Motorised Valves | Honeywell | Zone Valves | Toolstation

The auxiliary circuit (grey and orange wires) is commonly used to operate the boiler and/or the circulating pump. The auxiliary circuit could be set to work at a lower voltage than mains but it is normally carrying mains voltage. It works like this: One of the two wires, typically the grey, is connected to a permanent mains Live supply (about 230V AC in the UK). The other wire, usually the orange, is connected to the Switched Live feed to the boiler. However, if you need to replace the motor it may be easier to remove the powerhead so you can work on it in the open. Remember, on early Honeywell motorised valves (pre-1985) you can’t remove the powerhead without draining down first! 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 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. 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.

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Nearly all Honeywell valves have a powerhead (also called an actuator) which can be separated from the valve body. The valve body is the brass casting which is bolted into the pipework. The electronics in Honeywell motorised valves tend to be quite stable and show relatively few faults but the motor may fail after years of operation. Honeywell use Synchron motors and these are freely available but there are lots of cheap cloned motors out there. These look identical but, instead of the name SYNCHRON, they use the word Synchronous. Much of what we describe also applies to ACL Drayton motorised valves like the Drayton 2-port ZA5/679-2 22mm zone valve and the Drayton 3-port MA1/679 22mm mid-position valve. Iflo motorised valves and British Gas motorised valves have similar faults. It may also apply to the Tower VAL222MV motorised valve, the Siemens CZV222 motorised valve and the Flomasta 27900SX motorised valve.

Honeywell Home V4043H1106/U 2 Port Motorised Valve - Screwfix Honeywell Home V4043H1106/U 2 Port Motorised Valve - Screwfix

Only when both white and grey wires are energised (and the valve goes to the Heating Only position) can the orange wire get its 230V supply via the valve itself. (Remember, the orange wire can also get 230V from the cylinder stat if it is calling and a hot water program is on.) Slide the blunt end of the motor sideways until the flange comes out from the tab holding it down. This can be a bit of a fiddle. The motor then comes free of the valve, held only by the two wires which connect it electrically. These two wires may be blue (in a Honeywell original Synchron motor) or orange (most replacement Synchron motors). The powerhead or actuator is the electrical section. It’s comprised of a motor and some electronic components and usually has one or more microswitches. 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. V4043H1007 is a 2 port, ¾” BSP Female threaded, 5-wire, normally-closed zone valve with an auxiliary end switch

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If the valve motor fails, the motorised valve will not open. The valve will not then close the end switch and so will not complete the auxiliary circuit. The boiler will not fire (with no open pipe circuit to dissipate the heat), unless another motorised valve opens another pipe circuit and calls the boiler into action. This prevents the boiler firing and the pump running when there is no water circuit open. 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. The V4073A 3-port valve never closes water flow through the valve completely. There is always an open pathway from port AB to port A or from port AB to port B or from port AB to both ports A and B at the same time. 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. 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 Home 2 Port Motorised Zone Plumbing Heating 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. 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. System boilers may also have a diverter valve or zone valve built into them and might not have any external zone valves. If you know how to work safely with mains voltage electricity, the valve motor can be tested with a multimeter. With the mains electrical supply turned off and isolated, the resistance across the two motor wires (either both blue or both orange) can be tested. To test correctly, at least one of the two motor wires must be disconnected from the heating wiring circuit. A programmer and room thermostat (stat) are used to control heating times and room air temperatures. The programmer and room stat may be combined into a single programmable room stat.

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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. If the powerhead was removed from the valve to make it easier to change the motor, it must now be re-attached to the valve. The power head cover can then be refitted and secured with the single screw. Make sure it sits squarely on the powerhead, with no wires pushing out from the sides. 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 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). The commonest fault with Honeywell motorised valves is motor failure. Honeywell valve motor fault? Testing a Synchron valve motor