check valves

[rolymo]

Hi all.
I am going to fit a new bath tap one with a shower head combined.
Just need to know if i need to fit a double check valve to both cold and hot supplies.
The cold is mains pressure and the hot supply is gravity fed.
many thanks.

 

[ajrtd]

You'll need a double on the cold single on the hot.

 

[seco services]

but you'll probably find the shower will be a pain to get it to a reasonable temp to use being on cold mains and gravity hot.
the cold will over power the hot.

 

[bengasman]

cold mains and hot tank in mixer; that is asking for trouble