Advice on external hot tap

[redpis]

Hi,

I have an existing external bibcock which is cold water only, due to restrictions in space on the external wall, adding a separate hot bibcock is not possible.

I need to be able to switch from cold only at the tap when needed, but the more frequent usage will be blended water for filling a bucket to wash the dog or car.

I have attached a rough schematic of what I think might work, the idea is during normal operation the cold bypass is closed, giving blended water at the tap, when cold only is needed, I open the bypass valve and hey presto.

Would this work, or would it be better to install a valve at point A, isolating the output from the TMV, before opening the bypass, also would you suggest installing a cold water pressure regulator or are TMV 'forgiving' to differences in water pressure.

Thanks in advance.

 

[Newboy]

I'd be inclined to use a changeover valve rather than having to open/close two separate valves - for example http://uk.rs-online.com/web/p/produ...|prd|0486322&gclid=CIrhruLr6dACFQ4R0wod0skB1w

Most (good) TMVs will cope with some pressure difference but you need to check what the supply pressure difference is before selecting a suitable fitting.

Check valves are fitted to good TMVs but I'd fit DCVs to both H&C supplies within the building envelope (with suitable isolation& drain points to allow for testing)

 

[Madrab]

Buy a cheap thermostatic bar mixer and use the outlet to feed the tap, you can then adjust the temp as required. Feed the cold from the balanced supply at the un-vented to avoid any pressure differences. Even tho the bar should have non return valves built in I'd still double check and drain internally on the run from the mixer outlet to the bib tap.

 

[redpis]

Hi Guys,

Thanks for your advice it has really helped me decide what to do.

Cheers