Advice on House Plumbing setup

[jghome]

Hi,

Apologies in advance if more information is needed, however I will try and explain as fully as possible my challenge.

I have just moved into a new house - it's 3 years old and is 'eco', as such there is a heat exchanger rather than a boiler and hot water is distributed around all houses via underground piping.

The main water inlet is under the sink in the kitchen and from there it branches off around the house - there is a pressure gauge on the main water inlet which reads around 1.5bar.

Here is where I am a bit confused as in the upstairs and downstairs bathrooms the feed for the sinks seems overly complex, I can see the hot and cold feed come through the wall - however they appear to join together via a valve with a white cap - I've not come across this setup before and am trying to understand how it works.

The reason for the question is that I want to install a downstairs shower and need to understand if I have to replicate this valve arrangement for the shower.

Please ask if you need any more information or would like a picture of the under sink arrangement - and I appreciate any feedback anyone might have.

Thanks

Edit: Forgot to mention - I took the panel off the Bath upstairs and there is the same valve, when I turn the bath on 2 of the pipes get hot and one remains cold, there is also a mixer shower in the bath but I cannot see the same valve arrangement for the shower.

 

[Madrab]

A picture says a thousand words ... tho it sounds like they might be TMV's (thermo mixing valves), this is to ensure the hot water doesn't exceed a safe max at the outlet.

 

[dilalio]

As @Madrab above... Sounds like you have no control over the temperature of the hot water that is supplied to your property from a communal source. The devices you mention will definitely be TMVs and they are safety devices to prevent scalding from hot outlets. They are now a regulation requirement in most new builds. It also means you can have hotter water at the kitchen sink, where it is needed for food hygiene.

These are what you have...

 

[dilalio]

The reason for the question is that I want to install a downstairs shower and need to understand if I have to replicate this valve arrangement for the shower.

With your new shower you can include the TMV within the shower valve and would need to choose a product that is TMV2 rated.

Lots of info here
http://www.beama.org.uk/heating-and-ventilation/water-safety-and-hygiene/faq-tmvs.html