Check valve and submerged filling of CW tank

[Ben]

Can anyone shed any light on this:

I have a float valve in the loft I want to add a submerged fill so hat it fills quietly Just adding a section of pipe breaks WRAS rules as ther eis nothing to prevent bak siphon Presumably however as long as I have a WRAS approved check valve upstream of the valve I am ok -any water suked back up the pipe can't get past the valve. I know this is ok for outside taps, so ought to be ok here...

Any thoughts?

Cheers,

Ben

[The Medway Handyman]

You can buy float valves which have a flat tube extending into the tank so they fill quietly, but would collapse flat if any backflow occurred.

[Ben]

I have seen torbec valves like that, but wasn't sure if they'd be up to the job for a large tank - I wonder if you can buy (or make) a device to retrofit to a standard brass valve...

Ben

[Andy Hall]

This really depends on the water pressure and flow rate available.

If both are quite high, then filling a large tank is not a problem.

I have relatively low flow rate and pressure available in the loft and a large tank to fill, so fitted two Torbeck valves.

The floats are adjusted so that for a small draw off of water, only one opens - e.g. flushing from a toilet cistern during the night.

The other opens for larger uses such as shower or bath, in effect giving a much larger flow rate into the tank. I measured this as about 50% more than a single valve.

I wouldn't recommend using check valves if you are concerned about flow rate into a tank. They tend to nobble it quite a bit, especially if the pressure and flow are not high in the first place.

[TheScullster]

"Ben" wrote

The advantage of being able to hear the filling, is that leaks or hot-taps-left-running can become evident (when you realise that tanks are filling when they shouldn't be) IYSWIM. Particularly handy if you have kids.

Phil

[John Stumbles]

Yes, hang a bit of suitably-sized tube (e.g. plastic overflow) under the fill valve spout and reaching down below the water level in the tank. Make sure it's not an air-tight fit to the valve. It will mute the water going into the tank without any risk of back-siphonage.

[Ben]

I've seen layflat hosing that I think might be ideal:

is also lighter weight polythene stuff like that used on torbecs

(maybe like this:

but I would guess the former would be more durable. I can stick a plastic tube at the top end to hold it open and submerge the othe end. The tube can then be hooked over the valve to keep it in place, while leaving an airgap. Any thoughts? Would the tubing be ok for use on a domestic supply?

Cheers,

Ben

[John Stumbles]

OK if you've got some lying around, overkill to go out and buy some.

[Ben]

Ok - I came across another problem with the layflat hose - apparently all piping for use in hosues has to be approved by someone or other, and that stuff never has been.

Ben