Cold feed x 2?? To combi boiler

[Worrier61]

Hi
Helping a friend... The filler loop has been put on with a spanner rather than hand tightened, but I am curious about configuration... See photo.
Cold comes from the right, goes up hose and then down into a non return valve. That bit us what I would expect.
But it is T junction so water pipe continues and then goes up into the boiler. It then seem to be capped off at front of boiler.
I can understand that there may be older redundant piping before boiler. But why wouldn't it be capped before boiler.
The only other relevant info I think, is that both sets of taps toilet and kitchen sink are mixer taps. I've just seen that bathroom mixer only has one pipe. So it seems that everything is mixed at the boiler end so maybe it isn't capped after all.
I have mixer taps but these are fed by two pipes.
Just for my own sanity, is the set up at my friend's house common.
I had probably not tinker as it is different to what I have
Thanks for any info. I'm just trying to improve my undestanding

 

[oldbutnotdead]

Its a combi, that's why.
The filling loop goes to the (pressurised) heating circuit, the other cold water pipe then goes into the boiler and the contents heated to give hot tap water.

 

[ianmcd]

That filling loop is fitted the wrong way round, the non-return valve should be on the cold water mains side not the heating return pipe

 

[Worrier61]

Its a combi, that's why.
The filling loop goes to the (pressurised) heating circuit, the other cold water pipe then goes into the boiler and the contents heated to give hot tap water.

Actually I feel a bit silly now. Yes, mine too has the water continuing on. My only excuse is that because mine is a different orientation I simply didn't think about it in the same way. That solves that one!
Thanks

 

[Worrier61]

That filling loop is fitted the wrong way round, the non-return valve should be on the cold water mains side not the heating return pipe

Am very grateful for any replies. You are likely to be more qualified than me. Very likely. That part didn't concern me, because mine is exactly the same. In tvat sense I keep my loop partially disconnected, the only reason being, it's above a kitchen work surface and without hose protruding, I can fit a nice wooden cover over to hide the pipes

 

[Worrier61]

PS the non return valve is separate to the hose. The hose itself is symmetrical. Surely non return valve has to be that side otherwise water would simply come out of the sealed system?

 

[Worrier61]

Actually I feel a bit silly now. Yes, mine too has the water continuing on. My only excuse is that because mine is a different orientation I simply didn't think about it in the same way. That solves that one!
Thanks

Also, even more of a fool. The sink has I fact got two pipes going into the mixer.
Really I ought to delete this whole thread!
I've never worked out how to do that though.
So I suppose once you ask a stupid qu, it's there forever.
Mr Worrier
61 Acadia Av
(good job you don't know my first name)

 

[ianmcd]

PS the non return valve is separate to the hose. The hose itself is symmetrical. Surely non return valve has to be that side otherwise water would simply come out of the sealed system?

nope you want the ball valve on the system side so if you need to drain the boiler when working on it, you put the hose into a bucket and open the valve and it drains the boiler

 

[Worrier61]

Oh well you seem to know what you are talking about. Someone is coming to do some work on mine soon. He didn't seem alarmed that my non return valve is boiler side of loop.

 

[Worrier61]

I suppose instead to drain both these boilers you would just take off the non return valve. I realise not as slick as your method.
I'm now obsessed with thus fact you've shared. Every time I see a boiler I'm going to try and see if it's your configuration or 'mine'

 

[Elkato531]

That filling loop is fitted the wrong way round, the non-return valve should be on the cold water mains side not the heating return pipe

That double check valve doesn't have an isolation valve which is why it will have been put on the heating side. I'd be replacing the iso valve T with a plain T followed by a new filling loop with an iso-valve on both ends to give the configuration ianmcd suggested.