Ballcock question

[peweuk]

The pipe feeding water to our house from the supply is 22mm.
As it feeds 2 houses there is a branch outside the house where the 2mm pipe was reduced to 2 15mm pipes then to the meters.

Some months ago I changed the branch and meter used 22mm pipe to feed into the house and this seemed to increase the water flow at taps etc to a satisfactory level. Supply to the house is approx 3 bar now, compared to just under 2 bar before the pipe alteration.

The cold water tank which feeds the hot tank is one of the first branches off the feed pipe, and this was fine until a few days ago when we noticed water coming out the tank overflow.

I took out the ballcock on investigation I found a bit of grit in the ballcock which stopped it shutting down completely. So I removed the grit and re-fitted the ballcock. After refitting it started to 'hammer' very loudly as it shut off when the tank is filled.

Anyone any suggestions as to why this has started happening.

ALSO - i thought about changing the ballcock for a new one, but see that there are 2 versions available. One for high pressure, and one for low pressure.

What are the differences, and what would be the effect of fitting the 'wrong' one.
Do they differ in terms of the amount of water flowing, or is purely to do with pressure. If it is only pressure, would it be better to fit a low pressure one and turn down the supply using the isolator which can be adjusted - or would a high pressure one be be better.

 

[kirkgas]

if the tank is now not overflowing it is ok, when you turned the water off to strip the ballcock out you must have turned it back on harder therefore causing the noise, it is possible the washer is worn and causing a prob, in which case the washer itself can be replaced, if you decide to renew the ballcock you need to change it for the right one, if you fit high pressure ballvalve on low pressure pipe it will take forever to fill, and if you fit low pressure ballvalve on high pressure pipe it will make some noise when it refills, if you have 3bar im sure (i think!!) that will be high pressure but i cant remember

 

[TicklyT]

Turning down the isolator won't reduce the static pressure, it will only reduce the maximum flow rate, and the residual pressure at that flow rate. As soon as the float valve starts to close, the pressure will increase again as the flow through the valve decreases. Another problem is the velocity of the water through a partly closed valve tends to erode the edges of the seals, so the isolator either leaks, or won't work when you need it to.

The banging and rattling may be a sign the float valve is nearing the end of it's useful life. It may still shut off OK, but a lot of noise is often due to the mechanical components having worn enough to chatter about inside the valve body. Cleaning out the valve could have removed a layer of limescale etc. that was taking up the clearance, so now everything is that bit looser.

Low pressure float valves are usually intended for use on cisterns etc. fed from the cold water storge tank. High pressure valves are usually fitted on the mains water feed to the cold storage tank, and cisterns fed directly from the cold water mains supply, unless your mains pressure is quite low anyway.

Many valves are supplied with cones to suit either high or low pressures. Just fit the appropriate one when you install the valve.

 

[peweuk]

Thanks guys,

That gives me the info I need.

I'll definitely change have the ballcock I think, and ensure I get a ballcock with both high and low pressure valves so I can change them over if the one I fit isn't suitable.

Thanks again.

 

[Nige F]

The info you NEED is go and get a part 2 ballvave Only a RGI can waffle so much

 

[peweuk]

Thanks again guys.

New ballcock (part 2) solved the problem.

I have another question though.

I may be imagining it, but the tank appears to fill quicker although it looks like both the old and new ballcock have the same size valves (both white).

Does anyone know off hand what the 'flow' rate capacity of a ballcock is? (eg 2, 3ltrs/min)

 

[Nige F]

I don`t do technical answers - but it`s probably the diaphragm in the new valve is further from the Venturi ( what you call the valve ) than the old one when the valve is fully open , because it`s more flexible than the old one . As to the flow - it`s directly related to the pressure in the incoming main pipe . Calcs. I leave for RGI`s