Shower mixer check valve?

[ppm]

Just changing a bath shower mixer tap, there's no check valve installed at the moment, but do I need one? Combi boiler, not sure but think cold is mains fed. Can I just fit shower check valve in hose to protect shower head if placed in bath? I don't want to restrict water flow and the shower will rarely be used.

Thanks in advance..

 

[TeaTime]

What is the make and model please?

Generally it is not needed. Check the MI with your new mixer valve just to check though!

 

[ppm]

Thanks for the response. It's from Victoria plumb, called osca -tap34

 

[TeaTime]

Fit a single check valve on the hot and cold inlets.

I think this tap mixes in the body, so fit the check valves to prevent back flow.

It won't cost alot and your are probably re running pipework anyway.

Glad you told me the model now.

 

[ppm]

Many thanks

 

[Madrab]

Generally if both are mains fed and not tanked then that's a balanced supply of potable water and the risk of backflow contamination is minimal. Strictly speaking there should be a single check valve on the cold inlet to protect the cold mains but in your setup I wouldn't say it's essential, if it's this tap?
http://www.victoriaplumb.com/Taps/Bath-Taps/Bath-Shower-Mixer-Taps/Osca-Bath-Shower-Mixer_350.html - as it's not monotype it doesn't mix in the body.

To comply with the water regs though, and minimise contamination risks, your shower head should be installed whereby the head cannot reach the max spillover/overflow level of the bath or shower tray.
That water (CAT3) is a higher risk if backflow occurs and must be avoided, usually by the air gap.
A single check valve in the hose is not ideal as it only protects against CAT2 water so if using one then a double check valve is required.
Depending on the shower pressure that will determine the impact on the shower output.

 

[TeaTime]

Apologies, I looked at the wrong tap.