Honeywell 3 port Valve

[spearos81]

Evening everyone!

Looking for some advice regarding the Honeywell V4073 3 port valve. When the HW is on the CH is on too. I have looked at the valve and the manual lever is not returning to the rest position.
With the valve head removed the lever can be operated under firm pressure and will return to the rest position and the shaft of the valve turns freely by hand, however it's movement seems very limited.
Is it possible there is a reason why the valve isn't operating fully? Sludge? Wear? Deterioration?

Or should I be looking elsewhere?

Many thanks in advance,
Mark

 

[Dan Robinson]

Could be sludge, wear (deterioration )

Also it could also be a badly plumbed system with the heating Teeing back to the boiler after the hot water return, thus giving you reverse circulation.

Run the system from cold on HW only. See which pipes are getting warm on the offending rads. As soon as you have determined this - get some helper to switch on the heating and see if heat is swapped to the other pipe.

 

[misterdubya]

Edit... Dans covered it all.

 

[spearos81]

Could be sludge, wear (deterioration )

Also it could also be a badly plumbed system with the heating Teeing back to the boiler after the hot water return, thus giving you reverse circulation.

Run the system from cold on HW only. See which pipes are getting warm on the offending rads. As soon as you have determined this - get some helper to switch on the heating and see if heat is swapped to the other pipe.

Thanks for the quick response Dan.

So the fact that the manual lever on the valve doesn't return to the rest position does not necessarily indicate a problem with the 3 port valve?

This plumbing and heating mullarky is all new to me having just got myself on the housing ladder so excuse me if appear ignorant! I understand the rest position on the 3 port valve is the HW only position, and as I see it the valve will not move to this position?

 

[seco services]

So the fact that the manual lever on the valve doesn't return to the rest position does not necessarily indicate a problem with the 3 port valve?

It will only return to it's default position if hw was last port of call or you have isolated the electrics to the system.

I understand the rest position on the 3 port valve is the HW only position, and as I see it the valve will not move to this position?

Yes default is hw only.
It won't move to that position if ch was last port of call.

 

[spearos81]

Could be sludge, wear (deterioration )

Also it could also be a badly plumbed system with the heating Teeing back to the boiler after the hot water return, thus giving you reverse circulation.

Run the system from cold on HW only. See which pipes are getting warm on the offending rads. As soon as you have determined this - get some helper to switch on the heating and see if heat is swapped to the other pipe.

Ok just checked this on the kitchen radiator, on the opposite wall to the boiler (programmer is on boiler). Put the programmer on HW only and felt both pipes on rad, as soon as one started warming up I quickly switched programmer to CH and HW (it's a basic programmer with just HW or HW and CH). The other pipe did not get hot in the time it took the other end to get hot on HW only.

Also, the offending radiators are... all of them!

 

[spearos81]

So the fact that the manual lever on the valve doesn't return to the rest position does not necessarily indicate a problem with the 3 port valve?

It will only return to it's default position if hw was last port of call or you have isolated the electrics to the system.

I understand the rest position on the 3 port valve is the HW only position, and as I see it the valve will not move to this position?

Yes default is hw only.
It won't move to that position if ch was last port of call.

So when I switched off the boiler to remove the valve head, the manual switch should of returned to the HW/rest position?

Or with the programmer switched to HW only, it should also move to this position?

 

[jackthom]

Yes, certainly with all power disconnected the valve spring should return it to HW only.

 

[leytonjc]

your valve body may have seized, with the actuator removed try operating the valve spindle with your thumb and finger.

 

[spearos81]

your valve body may have seized, with the actuator removed try operating the valve spindle with your thumb and finger.

I can turn the spindle freely, although it has very limited movement - aout 10 degrees I'd say.

 

[spearos81]

Yes, certainly with all power disconnected the valve spring should return it to HW only.

So with power connected this doesn't happen and when removed the valve head/actuator works so it has to be the actual valve that's at fault?

 

[MANDATE]

Why not take the head off the spindle. Set spindle by hand to HW only. (CH port closed)

With head still off, switch programmer on to HW.
Boiler and pump will operate and if valve lets water pass to CH then valve is not closing (worn or sludge).

If water does not pass to CH and free to move then valve is OK.

If the head is also OK when it's off the spindle, then it might be causing some binding and misalignment when the securing screws are tightened.

If the head itself does not return to HW when HW is selected from other positions, the problem will most likely be 'gear teeth' on the quadrant or of course the return spring

 

[spearos81]

Cheers Mandate, I will give it a go.

Out of interest, can anyone tell me what type of valve is used in a 3 port valve? I'd like to at least try and understand how one could fail due to wear/sludge

 

[MANDATE]

I believe there is a rubber ball on the other end of spindle, off set of course and it can turn to block off one port while other is open, or it can be inbetween so no port is blocked.
I think a potterton may be slightly different because the spindle can turn full 360 degrees so most likely have a machined flat to achieve same result

 

[Hugh Jaleak]

Think the Honeywell (and others) employ the 'ball' method of operation. The Sunvic type (possibly others) use a rotating 'cylinder' with slots cut out. The flow from the boiler enters the base of the cylinder, cylinder is rotated by the motor to line the slot(s) up with the appropriate outlet port(s) allowing the water to flow in required direction.