Zone valve / power head mismatch

12 Mar 2013
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United Kingdom

I'm replacing a Honeywell V4043 valve power head (40003916-001) on the hot water system, sat between the boiler and water cylinder. I've come to fit the replacement but the power head seems to rotate in the wrong direction: open ("manual", flats horizontal) is OK, but closed on the valve looks to be a turn of 45* anticlockwise whereas the power head mechanism would want turn it 45* clockwise ("auto" or resting position, power head "normally closed"). It can't, so it just sticks somewhere between "manual" and "auto" when fitted unless powered, when all works OK.

The one I'm replacing is just the same, so I'm wondering if it was fitted in error. Am I missing something? If not, can you advise which power head I need for this valve?

Thank you!
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a little confusing, can you take a pic?

the bit in the middle of the brass body is closed when its across the pipe, when its open it will probably be a little over 45' and almost in line with the pipe its on
Hope these help, struggling to describe this well but in short the power head's range of motion seems to be opposite to that of the valve, like a mirror image


  • power head in auto position.JPG
    power head in auto position.JPG
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  • Valve setting with head at manual (powered) position.jpg
    Valve setting with head at manual (powered) position.jpg
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  • Valve when turned by hand.jpg
    Valve when turned by hand.jpg
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You have the correct powerhead. Put the lever in the manual position, it should be approx. 90* to the pipework. align the valve spigot to the same position and put the head onto the valve. It may take a little jiggling. The two studs will locte in the powerhead and you can tighten the screws. Then put the lever into the auto position and all should be well.

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