2 way zone valve

[mk2phil]

I have a 2 way zone valve fitted to the return pipe as it exits the HW cylinder. Its a gravity HW system.

It seems that the valve always closes itself unless the HW is on. When the HW comes on you can feel the 'arm' slowly open. When the HW turns off it quite quickly closes shut. Is this right - whenever the HW is off the valve should be closed?

I thought that the valve only closes when the stat on the cylinder reaches the required temperature? i.e. if the HW is turned off but the temp is still quite low then the valve stays open?

Also, when the valve is open and thus creating the complete curcuit, does this cause quite a quick flow for the gravity hot water? My CH is pumped and I would have thought that if you had both systems on at the same time, the pump would take all the hot water for the CH system and hardly any would gravitate to the cylinder?

Thanks for any help

 

[weareleeds]

If valve waould be mostly open & only controlled by cyl stst you would probably be going through a lot of synchron motors.In relation to pump it depends where it is sited ie if on return nr boiler it may actually help the gravity circulation but if on flow it may rob circs.

 

[pannierstan]

Ahhh that takes me back. The good old C plan.........

Or was it M plan or W.......

The mists of time are thick with this one.

 

[pannierstan]

Also, when the valve is open and thus creating the complete curcuit, does this cause quite a quick flow for the gravity hot water? My CH is pumped and I would have thought that if you had both systems on at the same time, the pump would take all the hot water for the CH system and hardly any would gravitate to the cylinder?

Thanks for any help

Isnt Gravity amazing. They knew how to pipe systems in those days.
Isnt it amazing that what you think would happen doesnt.
Thats because the Gravity circs on your system come from 2 different tapping on the boiler than the Pumped ones

 

[mk2phil]

Am I to take it from your replies that this is quite an old fashioned system? I was thinking about incorporating the HW system into the pump so that the HW tank heats up quicker and spreads the heat more evenly around the pipes - hopefully meaning that pipe noises in the joists will be quieter..?