Ballcock question

[Bob Minchin]

Hi All,

I want to change the ballcock on my cold water header tank in the roof with the objective of getting greater flow. This is because my hot warter system can drain the tank quicker than the mains can refil it. The feed pipe is 15mm and not practical to increase to 22mm but the orifice inside the ball valve is very scaled but even so is only about 4mm bore which must limit the flow severely ( much more than 15mm supply pipe(?)

I see there are four types of metal ball valves all to BS1212 Part1 - like 1 already have and part 2 with a lever with a right angle bend at the ball end which rather looks like it woul reduce the operating level in the tank - not good for my problem anyway Each type is available as high and low pressure options.

My mains pressure is about 2.5-3 bar. - we live on a hill top

I have been unable to find a reference as to the pressure range of each type of valve only a suggestion that older part 1 valves ought to be replaced with part 2 versions -

(so why are both types still sold?? I'm tempted to ask)

I assume that a low pressure valve part1 or Part 2 would have a larger orifice and hence better flow.

Can i use a 'low pressure' valve on my relatively low mains water pressure.

NB I do not want to use a plastic Fordham type valve as I have had numerous problems with these in toilet cisterns over the years and the diaphragms do not seem to last long at all.

Happy New Year

Bob

[ski]

Go to your merchants and buy a larger orifice to replace the one you have

[Bob Minchin]

Thanks Ski,

I did not realise that other sizes would be available as loose items.

Bob

[Andy Hall]

You can try. The effect if the pressure is too high for it can be water hammer as the valve is closing.

I've had good results with both Torbeck and Fluidmaster valves.

Another approach that you can try, that I've done with a pair of Torbecks (could be done with any valves), is to fit two valves. This has quite a dramatic effect on the flow.

[Ian Stirling]

Are "full bore" ballcocks available? I'm imagining a quarter turn ballcock, with a 10:1 lever system, and a bit of hysterisis. (sp?)

[Tony Williams]

Yes, I was in one of the sheds buying a new toilet ballcock assembly just the other day. They also packets of ballcock refurb parts. There were two nozzles in there, for high pressure and low pressure..... quite a difference in the hole diameter.

[Ed Sirett]

Firstly I think you should exhaust all the posibilites of poor flow/pressure in the mains.

If the _flow_ is poor due to poor _pressure_ then replacing the white high pressure nozzel in the standard ball c*ck with a red low pressure unit will help. If the standing pressure is high though the red ones may not shut off 100%.

Rather cheaper than replacing the ball c*ck with the next size up (the price between each size up seems to be x3). Is add another unit is parallel.

Is the tank being emptied because you have a serious pumped shower? In which case you may simply need to have greater capacity or more frugal usage.

[Andy Luckman (AJL Electronics)]

What merchants? What orifice?

See if this helps: