whats the difference between a double check valve and a

[macgee]

whats the difference between a double check valve and a single check one.

 

[gremlin16]

2 enclosed valves in double and one on single

 

[seco services]

the answer is in the question.

 

[macgee]

Great, so why do most items (ie, outside tap) ask for double check valve and not single. What would you use a single for?

 

[holty]

to stop a cat 2 back syphonage, i.e hot water(CAT 2) mixing with cold mains water (CAT 1)

 

[seco services]

an outside tap is more at risk than a hot/cold tap in your bathroom.

 

[macgee]

so would you use a single check valve on internal taps, if required. And a double where the risk is more, (ie, outside taps).

 

[holty]

somthing like that, say for instance your outside garden hose decides to go into a pond, thats a serious back syphonage risk that could enter your water supply, with taps internally they have what they call auk gaps etc to stop this.if you want to know more of this just buy the water regs its all in there.