checkvalves ... ?

[onion_soup]

hello

when to use check valves on mixer taps ? flow restrictor and service valves ? does flow rate need to be equal ? ie 9 litres/min hot and cold ?


simpletons guide please

what is diffenece between single and double checkvalves ( what does nut do in middle ) ?

thanks

 

[kevplumb]

single check valves go on tank fed supplies double check valves go on mains supplier
the clue is in the name

 

[onion_soup]

single check valves go on tank fed supplies double check valves go on mains supplier
the clue is in the name

and the nut in middle ?

I said simpletons guide double check valves on both hot and cold

what about flow rates ?

 

[ChrisR]

The "nut" is a screw which makes it a "verifiable" valve. Yes they restrict flow.

 

[kevplumb]

the nut in the middle
lets not go down that road

 

[Bahco]

The nut in the middle is to check the check valve (no pun).
Cut water supply and remove screw. Small amount of water from body will escape. If constant escape of water, valve has failed.

 

[--tom]

q1. Are check valves and non-return valves the same fitting?
q2. onion soup's first queries are still unanswered?
q3. If you plumbers went on a job where there was a problem of water supplies what would suggest to you that it might be the check valve in-situ or that a check valve was required?
q5. Where would you look for a check valve if you suspected it might be the problem?

 

[kevplumb]

if you have double check valves fitted must mains fed
1 yes the idea is to prevent back flow
if supplies are balanced should be ok
3 if problem with flow rate might suggest valve stuck
usually if an appliance ie dishwasher pressure washer etc has a direct mains connection
4 you missed out
5 close to the point of use or built into the tap

 

[onion_soup]

thanks for all replys

so the order of fittings for mixers taps is as follows ?

service valve>>>> flow restrictor >>>>>check valve>>>>>tap

???

is that correct ?

does hot and cold flow rate need to equal ?

I have 9litres/min hot and nearly double that cold ?

 

[kevplumb]

depends on the type of tap if your not sure cut the flow to the cold

 

[onion_soup]

depends on the type of tap if your not sure cut the flow to the cold

ok thanks

 

[kevplumb]

not being sarky some taps mix first
so it can cause probs which you know as you fitted check valves

 

[ChrisR]

Depends what supplies the mixer tap has. If they're from mains for cold and a Combi for hot you don't need check valves because they're both at mains pressure. The Combi will have a flow restrictor to keep the hot hot, which is often better taken out.

If your tap keeps h & c separate right to the end of the spout as in most kitchen mixers, you don't need the check valve even if hot one is gravity fed. Check valves in taps are very restrictive. Won't matter on mains but slows gravity supply a lot.

I don't think anyone would need a flow restrictor unless mains pressure extra high.

 

[onion_soup]

Depends what supplies the mixer tap has. If they're from mains for cold and a Combi for hot you don't need check valves because they're both at mains pressure. The Combi will have a flow restrictor to keep the hot hot, which is often better taken out.

If your tap keeps h & c separate right to the end of the spout as in most kitchen mixers, you don't need the check valve even if hot one is gravity fed. Check valves in taps are very restrictive. Won't matter on mains but slows gravity supply a lot.

I don't think anyone would need a flow restrictor unless mains pressure extra high.

thanks everyone for information