What kind of check valve, if any, is required on the feed to WC
cistern? Or are they usually built into the cistern these days?

R.

"TheOldFellow" wrote in message
. ..
What kind of check valve, if any, is required on the feed to WC
cistern? Or are they usually built into the cistern these days?

There is no requirement for a check valve in a wc cistern as there can be no
back siphonage due to the air gap between the outlet and the water.

On Sat, 29 Aug 2009 18:28:33 UTC, "Heliotrope Smith"
wrote:


"TheOldFellow" wrote in message
. ..
What kind of check valve, if any, is required on the feed to WC
cistern? Or are they usually built into the cistern these days?

There is no requirement for a check valve in a wc cistern as there can be no
back siphonage due to the air gap between the outlet and the water.

Air gap or collapsible tube.

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On Sat, 29 Aug 2009 19:28:33 +0100, Heliotrope Smith wrote:

There is no requirement for a check valve in a wc cistern as there can
be no back siphonage due to the air gap between the outlet and the water.

But you do need to make sure the filling (ball-float) valve is a suitable
type. One occasionally sees a "Part 1" valve, which has its discharge
below the centre line of the valve, fitted to a cistern on which the
overflow outlet is on the same centre line as the fill valve. This means
that under overflow conditions the fill valve is discharging under
the water level of the cistern rather than over it, so there's no
air gap, contra the regs. The correct type of valve discharges above the
water level at overlfow.



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John Stumbles -- http://yaph.co.uk

Extreme moderate