I have a Honeywell 2 port valve (which looks like a silver box) which is situated close to my boiler. This valve has a small lever at the bottom of it. What I want to know is does this lever move when the valve is in operation? Im sure it used to but at the moment it does not.... So the only difference between the two valves is the orange wire on the downstairs is not going live. which leads me on to why I've posted this topic. When I put the hot water on, the boiler (a 10 year old baxi solo) will run for about 10 mins before the overheat light comes on, followed by banging in the pipes. I basically want to know whether the 2 port valve may be malfunctioning, causing this problem. I had a BG engineer in but all I got from him was "flush the system" so I want to do some detective work myself. If fitted in a confined space, sufficient ventilation must be available to keep the valve within its ambient temperature range and access must be provided to remove the powerhead if necessary

Honeywell V4043H 1056 - 2 Port Motorised Zone Valve 22mm Honeywell V4043H 1056 - 2 Port Motorised Zone Valve 22mm

The other valve is the same the blue wire when connected to the junction box loses 240v not sure why but red herring i think. All our products are guaranteed for a minimum of 1 year (radiators vary - see individual product specifications, copper tube 25 years) but many offer longer warranties from the manufacturer, which you may need to register for.

If the motor is receiving 240v (on the brown and blue) it should rotate the spindle about 15 degrees and operate the microswitch. Sounds like the motors stuffed...they either properly die or partially and don't have sufficient torque. I'm assuming that you've got no hot water due to the overheat malfunction - in which case there's nothing to stop you hooking the valve open permanently if this resolves the banging (and simultaneously getting you some hot water) until we determine why the valve isn't opening. IF it is a faulty valve, these aren't difficult to replace. The Honeywell 22mm motorised 2 port zone valve has a wide range of flow control applications in domestic and light commercial central heating systems. V4043H (normally closed) models have end switches for electrical control of pump and/or boiler; the V4043B (normally open) model is particularly suited to control solid fuel systems, as it will always fail-safe in the event of a power failure. I Have tested the wiring from the Thermostat through the wiring centre to the valve wiring where the light brown wire becomes live when thermostat is turned but the orange wire does not go live? I have placed the valve manually on open.

Honeywell Home 40003916-001 2 Port V4043H Replacement Honeywell Home 40003916-001 2 Port V4043H Replacement

If you turn the hot water on and the programmer instructs the valve to open, then you should feel the lever will move freely (try to move it before you turn the programmer to the on position - you will feel some resistance, to compare the difference).Correct. I've not really got access to hot water. I say not really, as the boiler will run for ~10 mins, then the overheat light will come on, and then banging will occur in the pipes. This banging occurs due to air in the pipes. If I goto the loft and bleed the top-most valve the banging will go away. I can then use the HW again but I end up having the same problem. I was not getting any voltage reading on pin 10 on the wiring for the boiler which I think is switched live for the boiler. As Boilers and radiators are installed by third parties, they do have to install in compliance with regulations and manufacturer standards to get the full benefit of the warranty.