Mystery of the plastic pipe filling in to the Cold Water Tank

[spader]

Typical old trick to try and stop a water hammer by creating an air buffer. Never really worked as the water absorbed the air in the pipe.

So it could be replaced with a 90 degree elbow, or straight bent pipe then?

 

[denso13]

So it could be replaced with a 90 degree elbow, or straight bent pipe then?

Yes, no problem.

 

[spader]

Yes, no problem.

I read that 90 degree elbow would decrease the flow of water. Would it have been another reason for adopting the raised end pipe with a cap?

 

[terryplumb]

I read that 90 degree elbow would decrease the flow of water. Would it have been another reason for adopting the raised end pipe with a cap?

No ,one elbow instead of the Tee wouldn't make any appreciable difference.

 

[denso13]

Would it have been another reason for adopting the raised end pipe with a cap?

No, it's a DIY water arrestor.

 

[spader]

No, it's a DIY water arrestor.

Thanks for your confirmation.

 

[spader]

Could it be that it goes the other way and provides drinking water to a bathroom?

The only drinking water we use is the incoming mains water pipe straight to the kitchen cold water tap. All the rest taps are for washings and toilet cisterns.

 

[thetman]

Is it a mains feed to a shower and the water is coming back via the cylinder and the mixing valve ?

 

[spader]

Is it a mains feed to a shower and the water is coming back via the cylinder and the mixing valve ?

Yes, that was what I was guessing, but wasn't sure 100%. But it seems the most plausible case.
I am going to switch on the shower, and shut the mains rising full bore valve, and see what will happen to the shower water flow tomorrow. Will update here with the result.

 

[spader]

Is it a mains feed to a shower and the water is coming back via the cylinder and the mixing valve ?

I have ran the shower, and while it was running, went up to the loft, and shut the mains rising pipe to the cold tank. When I went to the shower, it reduced the water flow by 80%. It was still flowing the water, but it was obvious that the mains rising pipe shut off has reduced the water flow drastically.

I then went downstairs, and turned off the incoming mains water valve, and the shower totally stopped as well.

So, the grey plastic pipe is for the electrc shower, and maybe there is another pipe from downstairs coming up, and connected to the shower, it seems. Maybe initially the shower was fed from the downstairs mains pipe, but the water pressure was not storng enough, so they installed another pipe tapping off from the mains rising to the cold tank, and connecting the plastic grey TEE and pipe, and added to the shower?

The filling in to the cold tank from the grey plastic pipe was maybe unused returning water? It seems now a lot clearer.
Thanks for all your input and information on this topic.