combined toilet bidet back flow prevention

[malc]

customer would like combined toilet bidet fitted, spray is fitted to the pan, not hand held hose, she has unvented system.
does anyone know what back flow prevention can be used ?
are check valves on supplies to the mixing valve sufficient ?
wras advice seems unclear for unvented systems.
thanks in advance for any suggestions or advice.

 

[rpm]

Seperate tank for supply?

 

[steadyon]

1. As rpm says, separate tanks for hot and cold with air gaps for backflow prevention.
2. Check valves are not adequate safeguard against Category 5 fluid back flow / back syphonage protection.

 

[malc]

thanks for your replies guys, that is what I thought when i read the wras guidlines.
not an easy install then.

 

[Ben-gee]

Not cheap or easy to do it properly in uk.

 

[ShaunCorbs]

Cat 5 risk so break tank with weir and pump also 15l unvented so it’s not just cold water

 

[Stigster]

As you've been told, seperate supply to bidet seat from a tank with an airgap. There are no mechanical backflow prevention devices for Cat. 5 water.