Changing taps - can't work out the cold flow set up

[clonkel]

Hi, I am a DIY plumber and was going to change the mixer tap in the utility room (the old kitchen from the 70's) and I am puzzled by the cold flow.

On the image starting from the pipes in on the bottom of the cabinet. On the left is hot, on the right is cold. The cold services the tap and the washing machine. There is an isolation valve for the cold tap and a separate plastic tap to isolate the washing machine. I have no issues with these apart from every conceivable joint/valve is being used.

The middle pipe at the bottom of the cabinet is also cold. It has an isolation valve with the blue tap and feeds around and into the cold tap/washing machine feed. Although this does not stop me from changing the mixer tap I have no idea what it does and why it runs this way. Any ideas?

Also, would I be better off remaking everything as at present there is copper pipe to the tap and I can replace with tails feeding into isolation valves as well as removing the push fits and replacing with various end feeds and replacing the plastic tap for the washing machine with an isolation valve with handle.

Thank you

 

[Aquarius]

I can only fully see a full bore isolation valve (blue handled) and partil see a blue handled valve, but could be connected to the hot for the washing machine? Take a few more photos, or one a little further back. Also as for changing the pipes, that’s a personal preference generally.

 

[Ric2013]

Are you saying that the pipe seems to go around in loops and then back on itself for the washing machine?

This sort of thing is quite common - seems to occur when modifications are being made in a hurry and getting access where required to make a logical connexion was too much hassle, or perhaps results an amateur plumber who, lacking the confidence/materials/tools to cut anything back, always connects to the end of the existing pipe. The end result can still work but be quite amusing - I've seen a pipe run around the entire circumference of a room for no logical reason.

 

[clonkel]

@Ric2013 @Aquarius

thank you for the replies. Here are some more images. The two cold pipes (middle and right) connect back into each other. I have no idea why and that is the question really as the flow is upward to the tap and washing machine so its not 'splitting off' the cold flow. Thanks

 

[Ben-gee]

Try removing the plinth and look under the cupboard, it may show you what’s going on.

I suspect one of them is the incoming main and the other is going off somewhere in the other direction - maybe outside tap or up to tank?

 

[Aquarius]

I think you have a feed coming in vertically one way, the tee off for washing machine, and then back onto the cold main, you may have a garden tap. You could always turn a valve off, and see what stops.

 

[Timmy D]

The pipe going straight up to the tap is the supply.

The top tee feeds the washing machine.

The lower tee as stated above, feeds something else.

Outside tap or there could be a mixer to lower the hot temp below the plinth.

 

[clonkel]

@Ben-gee @Aquarius Thank you for the replies. I have attached a flow I drew and a shot from under the cupboard. The middle cold still makes no sense to me and I don't see the point in it being there. I must be missing something.

The outside tap is in the kitchen (different room) and we have an unvented system with one of the pipes in the image running into the waste (pressure release from main tank).

The washing machine (see diagram) is serviced from above where the second (middle) cold joins the right hand cold in.

thank you again

 

[clonkel]

Thinking about this the best answer I can come up with is: The room used to be the main kitchen and is now a utility room. I would 'guess' that the middle cold pipe was running somewhere else and it was 'cleaned' up by running it into the existing cold to the tap. Being a DIY plumber is it best to keep it as it is or do I cap it off with a stop cap end?

thank you

 

[Ben-gee]

If it ain’t broke, don’t fix it.

 

[clonkel]

If it ain’t broke, don’t fix it.

Maybe that is the problem with us DIY plumbers, can't help ourselves.

thanks

 

[Ric2013]

If you turn off that slotted screw isolator, what stops working?

 

[Timmy D]

If you turn off that slotted screw isolator, what stops working?

And what stops with the blue iso? Which one stops the tap above? That’s your supply

 

[clonkel]

@Ric2013 @Timmy D If I turn off the slotted screw isolator or the blue one then nothing happens. Apart from the slotted iso leaking of course. I have to turn off both for the cold to stop.

thank you

 

[Ric2013]

@Ric2013 @Timmy D If I turn off the slotted screw isolator or the blue one then nothing happens. Apart from the slotted iso leaking of course. I have to turn off both for the cold to stop.

thank you

So there would appear to be two pipes in parallel. Well, that's interesting!

All I can imagine is that one formerly went elsewhere and they have been run in parallel to avoid capping one and leaving a dead leg.

 

[clonkel]

So there would appear to be two pipes in parallel. Well, that's interesting!

All I can imagine is that one formerly went elsewhere and they have been run in parallel to avoid capping one and leaving a dead leg.

Yes that was my thought as the room was the old kitchen so would possibly had a pipe run elsewhere. I guess the only thing to do is leave it alone as there are two cold feeds into the cabinet and going to find out the source or where it initially branches would be too difficult under the floor somewhere.

thank you

 

[Ric2013]

Yes that was my thought as the room was the old kitchen so would possibly had a pipe run elsewhere. I guess the only thing to do is leave it alone as there are two cold feeds into the cabinet and going to find out the source or where it initially branches would be too difficult under the floor somewhere.

thank you

Or you could run one to the tap and one to the washing machine?

 

[Timmy D]

@Ric2013 @Timmy D If I turn off the slotted screw isolator or the blue one then nothing happens. Apart from the slotted iso leaking of course. I have to turn off both for the cold to stop.

thank you

Just want to confirm this, how long did you run the tap after turning each valve off during testing?

If one line supply’s something else and you only tested for a brief moment it could be residual water in one of the lines.

 

[Ric2013]

Could an unvented cylinder without check valve be backfeeding through one of the lines?