Thermostatic mixer shower cold feed

[johnbuckley]

Volunteered to fit my daughters bathroom as she doesn't have the money to pay a tradesman and as I had done similar quite a few times my name was in the frame!
I have come up against something a bit confusing and I'd be grateful for some opinions please.
On removing the wet wall and (apart from being a mess) looking at the shower water connections, the hot feed is connected to the bath hot pipe with a service valve and the cold feed goes up into the loft. I have followed the pipe in the loft and it is attached to a 15mm copper pipe which goes right to where the combi is fitted below. on looking at the boiler, there is a 15mm pipe is going into the wall and I am assuming straight up into the loft with nothing else attached!
I am a bit confused as to why the cold mains feed is being taken all the way from the boiler, if indeed it is, when it can be tee'd off the bath cold mains which is only 3 feet away.
I could just connect it all up as is but apart from wondering why, I am concerned that there will be no cold water service valve for the shower whereas the hot one is easily accessed behind the bath panel. I'm inclined to cap off the loft pipe and take the feed from the bath cold water pipe.
I've attached some pics and I'd be grateful for some opinion please.
Thanks in advance.

 

[CBW]

The part circled blue is the safety discharge pipe, this isn’t the cold feed and is usually only operating if there’s an expansion related issue, the pressure relief valve isn’t seated or the filling loop is left open. Perhaps the Combi came at a later date? It would make sense to get rid of the passive dead leg and use the feed under the bath.

 

[johnbuckley]

Thanks for your reply Chris.
I was just guessing that the pipe circled blue was the one that went into the loft and to the cold feed of the shower as it seemed to be in the right place! I just can't understand why the shower cold supply comes all the way from the area of the boiler across the loft to the shower.; I can't actually see where it's connected; any idea why this would have been fitted this way when it's clearly easier to connect under the bath?
I will probably run a pipe from the cold under the bath via a service valve as you say; and just cap the other other one off.

 

[terryplumb]

The cold coming from the loft may be a relic from pre combi installation ,where a gravity fed cold would have come from the loft tank ,to be balanced pressure to the hot,also gravity fed.
But hey...who knows !!

 

[Madrab]

.... and chances are that cold feed from the loft was feeding an electric shower at one point, so there was no need to add a new one if one was already there.

Of course, it's always good to have the shower H& C fed from the same place through isolators, makes things much easier when it comes to servicing.

 

[johnbuckley]

Thank you al for your replies. Yes there has been a 'normal boiler' pre combi all the old tanks etc have been left in the loft! Maybe an electric shower at one point.
I'll just take the cold feed from under the bath via a service valve.
Thanks again

 

[Hugh Jaleak]

I'll just take the cold feed from under the bath via a service valve.

Don't forget to cap off the current feed at source to remove the dead leg.