Check valves

[dfowler]

OK I give up. Where do check valves/double check valves go? They are as cheap as chips so better to fit now rather than rip the wall apart later!
D

 

[chrishutt]

Wherever they go, you'll need to have access to them for maintenance purposes so don't lose them in walls.

Typically they would be fitted on bath/shower mixer supplies since there is an obvious risk of backsyphonage of bath water through the shower hose.

Also if a mixer valve takes water from tank fed hot and mains cold. It may well be that the water regulations require more extensive use, but I have to admit to not knowing chapter and verse on this.

 

[dfowler]

Hi Chrishutt,
Access provision noted.

So going back to first principles, wherever hot or tank water could siphon back into cold main via defective sealing washer???

Presume kitchen sink mixer tap, dishwasher, washing machine
, outside taps also.
Thanks DF

 

[Paul Barker]

Outside tap wants double, most outside tap kits incorporate one. You can buy a "shower check" which fits in line with the shower hose. Quite hard to get hold of, one of the catalogues does them, don't remember if it's bes or screwfix. My local plumb centre had some before the good people left and numpties moved in. Now they look at me like I'm an alien when I ask for them.