Check valves/non-return valves

[llykstw]

I understand that these valves only allow water to move through in one direction, and so prevent "backwash". Is there any merit in fitting one of these to every pipe immediately before it goes into an appliance, e.g. shower, toilet, sinks etc.? Would it reduce water hammer, and prevent the annoying situation where turning a tap on or off causes the shower to drip a few times?

 

[AlanE]

If you fit one on the inlet side of a heat producing appliance - ie boiler, water heater etc - you would also need to install an expansion vessel suitable for potable water, between the check valve and appliance.

Alan

 

[llykstw]

If you fit one on the inlet side of a heat producing appliance - ie boiler, water heater etc - you would also need to install an expansion vessel suitable for potable water, between the check valve and appliance.

Alan

Thanks - I'm only thinking of fitting these to the pipes in the bathroom, so I don't think this will apply?

 

[AlanE]

But why??

Alan

 

[peter anderson]

you don't need check valves where the water level won't reach the hole supplying the water. e.g. cisterns, sinks and baths

 

[peter anderson]

you only need one for showers if the shower hose is long enough for the shower head to be under the level of the bath water