Water softener - new build flat - unfamilar pipe layout

[readingsteve1983]

I've just moved into a new build flat, and am looking at getting a water softener installed. I don't have enough space under my sink, but I'm not that fussed about having a drinking water tap, so I was looking at maybe putting it in the utility cupboard.

However, my understanding with water softeners is that *usually* they are connected at the mains, and then the softened water is passed to the boiler, etc. However, in my utility cupboard, I can see the cold mains feed - but am confused as there seems to be a separate hot feed.

Photos are below - could someone more knowledgeable/experienced than me clarify? The pipes that go off to the right look like they go into the under floor heating.

I do believe there maybe some sort of communal water heater, which would explain it. But does this mean I can't have a water softener? Or if I do, it will only soften the cold water

Any help would be appreciated!

 

[ShaunCorbs]

Your mains water is there blue lever valve left side

 

[readingsteve1983]

Your mains water is there blue lever valve left side

Hi Shaun - yeah I realise that, but is this what feeds the hot water too? I may be wrong but is the hot feed coming from elsewhere?

 

[ShaunCorbs]

Hi Shaun - yeah I realise that, but is this what feeds the hot water too? I may be wrong but is the hot feed coming from elsewhere?

It’s fed from the black box (hiu) unless you have a cylinder in your flat ?

 

[readingsteve1983]

It’s fed from the black box (hiu) unless you have a cylinder in your flat ?

Nope, no cylinder in my flat. If it comes from the HIU, does that not mean the hot water comes from elsewhere? ie: not from my cold mains, and can't be connected to a water softener?

Apologies if confusing - I'm not 100% sure what a HIU does? I'm assuming there is a communal boiler somewhere in the building and that's where my hot water comes from?

 

[ShaunCorbs]

Hiu will supply your hot water and ch from a main set of commercial boilers

 

[readingsteve1983]

So basically I can only soften my cold water?

 

[OffshoreGas]

The HIU (heating interface unit) acts as a heat exchanger between you and the communal heat source. I would be very surprised if the communal side wasn’t well with filtration etc. I don’t see why you can’t fit a water softener where the main enters your property.

 

[readingsteve1983]

The HIU (heating interface unit) acts as a heat exchanger between you and the communal heat source. I would be very surprised if the communal side wasn’t well with filtration etc. I don’t see why you can’t fit a water softener where the main enters your property.

Thanks OffshoreGas. I think the fact it's called a heat exchanger is what is confusing me. Is it literally a mechanism for transferring heat from one system to another (ie: the heat is used to warm up the cold water from my mains feed)? Or does it mean the heated water comes into my property, separately from my cold mains feed?

 

[ShaunCorbs]

That’s what’s inside

From the top left

1st pipe common return
2nd pipe common flow
3rd pipe eg top right set cold water in
4th hot water out
Bottom pipes

Left heating flow (out)
Right heating return (in)

 

[ShaunCorbs]

So basically I can only soften my cold water?

Yes you can fit it after the blue lever valve

Your plumber should know how to connect it

 

[OffshoreGas]

Yes a heat exchanger is means of transferring heat from one fluid to another.

They HIU’s are available in different configurations, I think normally in the U.K. the communal water is used in the CH circuit in the flat. The heat exchanger is used for the hot water that’s comes from your taps.

You’re most likely get lime scale build up on the HW side as this water doesn’t contain chemicals to prevent.

 

[readingsteve1983]

Yes a heat exchanger is means of transferring heat from one fluid to another.

They HIU’s are available in different configurations, I think normally in the U.K. the communal water is used in the CH circuit in the flat. The heat exchanger is used for the hot water that’s comes from your taps.

You’re most likely get lime scale build up on the HW side as this water doesn’t contain chemicals to prevent.

So you're saying that - if the normal UK configuration - the water going round my under floor heating is heated communally, and the hot water that goes to my shower/taps comes from my cold mains, and gets warmed up through the heat exchanger?

 

[ShaunCorbs]

So you're saying that - if the normal UK configuration - the water going round my under floor heating is heated communally, and the hot water that goes to my shower/taps comes from my cold mains, and gets warmed up through the heat exchanger?

Correct

Which in turn is heated by the communal boilers (hot water)

 

[readingsteve1983]

This matches up with what the product page (from @ShaunCorbs's post) says:

"The instantaneous hot water heaters inside each heat interface unit shall heat incoming mains cold water via a plate heat exchanger using heated water from the community heating system."

Direct FlatStation HIUs

 

[readingsteve1983]

Correct

Which in turn is heated by the communal boilers (hot water)

Thank you! 😀

 

[Chirag]

Thank you! 😀

Hi I have a very similar set up - if I understand this correctly, it means it’s worth investing in the water softener for my cold mains inlet as it will soften all the water in my flat including the hot and cold used in all appliances and showers - right? My underfloor heating is electric.

Thanks in advance