Overflow in main water tank

Here are some pics (click to enlarge) of the thing I keep replacing:

The part on the left hand side of this picture isn't usually replaced. I just unscrew the nut and put the 3 other bits (as a single unit) on the right hand side of the picture onto the existing thread/nut which is sticking through the wall of the tank. The arm with the ball on it goes into the slot that you can see in the picture below.

The unit above is about 3 months old.
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If you look at the first pic you can just see the nozzle, it looks low pressure, can you take it out and show it with the size of the hole.
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Sorry Mac.

Its all to do with Water Regs Back Flow Prevention.

On your ball valve the water comes out of the bottom, if there is a certain set of circumstances that arise then there could be contamination of the water mains.

ie, if the ball valve fails and you water level reaches the outlet on your ball valve, if the water main were to then break in the street, all the crap in your tank could then be sucked into the main by back flow(siphonage).
The watermain gets reinstated and anyone down the line from you could end up with the crap from your tank in their cuppa.

The newer valves have the water coming out from the top of the valve, with a plastic u-bend attached.

Hope this expains it bit.

So I think you should invest in a newer type valve, you could then easily change the internals to cope with the higher pressure.

Does this not need swapping out for a part 2 then scruff

Part 1 is perfectly ok on potable water, where there's no risk of contamination.

A part 2 ballvalve has the outlet on the top of the valve, against the bottom.

Personally I would buy a part 2 high pressure valve and change the lot, not just the end bit.

Those 2 are essentially the same valve, just made by different companies.

If you look at your current valve and the last 2 you posted, on the top of the newer ones there is a plastic elbow on the top, thats where the water comes from.

On yours it comes from the bottom.

As for differing pressures, they should come with 2 different coloured nozzles.
One has large opening in the nozzle for low pressure and the other has a smaller hole for high pressure.


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