Manually over-ride a 3 port valve to mid position?

[dominoman]

I have a very old Honeywell 3 port valve in my house which has stopped working.

From what I read they normally default to hot water if they fail, but mine is the opposite. The manual lever goes up to Central Heating, but when CH is off and HW on, it doesnt spring back.

I've tried to free it up by jiggling the spring and adding lots of WD40, but no joy.

Unfortunately replacing it is a massive ball-ache. It's located behind the tank between pipes - and being an old one the head is not seperate.

So, my question is...
Is there a way I could wire it so it stays in the mid position (HW and CH both)? That would be fine for winter as I always need both on.

 

[Daveydub]

Turn off all electrics to system on main supply not t.clock. Does it now revert to w.only position?
Manually open and put hw only on.

 

[dominoman]

Thanks. When I turn all the power off it doesn't return to HW position, but if I move the little cog inside with a screwdriver it does. There is a spring there so I guess that is supposed to move it to HW automatically, and doesn't.

 

[Daveydub]

Having got it to hw only position, manually open valve to mid-position & run hw only. This should give you hw & ch for the time being. If you can remove the cylinder stat from the cylinder then it will continue to run regardless of hw temperature but be warned that hw from tap will now be much hotter than it used to be so be careful with kids.
It sounds like the valve has probably got very stiff so springs are not strong enough to return the valve spindle.
It may still be possible to obtain a replacement for this valve & rebuild it in place but if access is very difficult perhaps rebuilding will be no easier than replacing it.
I did obtain a couple of the old type of valves a week ago (28mm)
You could just replace the ball & plate:
http://www.honeywelluk.com/products...ve-Spares/Motorised-Valve-Spare/V4043-Spares/
but as your head is 25 years old or so it is probably a good idea to replace this while you are at it.

 

[dominoman]

Great. Many thanks Davey! I will do that, and then will get a replacement fitted. Given the age of the unit I think I'd rather just replace it now with a newer one that allows the head to be removed separately from the body. The one I have requires a full drain-down to fit.