Storage Cistern Water Regs kits ?

[Agile]

Does anyone know why the standard kit has an overflow connection which dips down about 120 mm?

In the normal course of events the installer will have fitted it so that at the set level the bottom of that pipe is ABOVE the bottom of the overflow.

So if the level rises above the overflow point then the siphon action will ensure the level falls until the ball valve opens and the overflowing will continue until someone takes some action!

Tony

 

[bathstyle]

Single most informative post that I have read in probably 6 months

 

[bathstyle]

Just thinking about this a little more, the ballvalve would have to be letting by a lot for syphonic action to take place, a slow drip wouldn't let this happen would it?

 

[Agile]

In the case I encountered, the ball valve had jammed slightly and the level rose until the water over flowed.

The level then fell under the action of the overflowing until it had lowered sufficiently for the ( now freed ) ball valve to open.

So as the overflow was still dipping into the water and the ball valve still filling the cistern, the overflow continued to flow by siphon action!

It continued all weekend like that as the owners were away. Unfortunately there was a slight leak in an over flow connection and that dripped onto and eventually through the ceiling.

Tony

 

[kevplumb]

Does anyone know why the standard kit has an overflow connection which dips down about 120 mm?

supposed to stop draughts i think

 

[bathstyle]

I assumed it was a rhetorical question?

 

[bathstyle]

I once did a job where I had to replace a 100 gallon galvanised cistern.

This thing was built onto a specially made lead tray, all nicely bossed corners and it had a lead pipe welded onto the bottom which extended ouside through the soffit next to the overflow/warning pipe.

An early warning pipe for when the galvanised would eventually rust through, very clever I thought!

 

[Nige F]

how much did you get for the lead

 

[Corgigrouch]

I would suppose that most folk would ignore a drip until moss grew all over where ever the drip landed, but a sudden gush in the event of a ball valve having a bit of a drip would get the house holders attention... I figured that it was to prevent cold draughts entering the insulated header too..

 

[picasso]

I thought the dip pipe was to stop spiders etc getting into the water.

 

[clf-gas]

I thought the dip pipe was to stop spiders etc getting into the water.

The mesh screen is in there for that.

 

[muggles]

Hmm not come across this before but now you mention it I can see how it could definitely be a problem. Not really sure what the dip tube is for, as has been said the mesh screen stops the bugs getting in. Maybe the solution would be to drill a series of 2mm holes on the top of the tube, which would prevent draughts but also provide an anti-siphonic air inlet...

 

[doitall]

Does anyone know why the standard kit has an overflow connection which dips down about 120 mm?

supposed to stop draughts i think

Give the man the prize.

To stop draughts and prevent freezing.

 

[Goldberg]

Does anyone know why the standard kit has an overflow connection which dips down about 120 mm?

AFAIK it's intended to reduce the likelihood of airborne contaminants from entering the stored water. For this to work the water shut-off level should be set to be above the bottom of the dip tube.

There should also be a mesh screen to prevent leg-borne contamination.

In the normal course of events the installer will have fitted it so that at the set level the bottom of that pipe is ABOVE the bottom of the overflow.

What is "the bottom of the overflow"? Are you aware that this is a warning pipe connection, not an "overflow" facility?

So if the level rises above the overflow point then the siphon action will ensure the level falls until the ball valve opens and the overflowing will continue until someone takes some action!

This is complete nonsense. There is no siphonic action involving the warning pipe, because the water trickles out before the horizontal part of the outlet is even half full.

Single most informative post that I have read in probably 6 months

But it doesn't contain any correct information.

BTW, you can't prevent static water from freezing with insulation. No matter how thick it is, if you leave the water in a below-freezing-environment for long enough, it will freeze.

The primary purpose of the insulation in a "Byelaw 30" kit isn't to retain heat energy - it's to keep heat out. There is a significant risk of Legionella in stored water vessels, and keeping the temperature below 20°C is important for a cistern in a loft, even more so where the cold supply to a mixer shower is fed from a cold storage cistern.