Crud in copper pipe

[MortarThePoint]

The pipework leading to a level ball valve, Caleffi 533201 PRV with integrated check valve and on to my unvented cylinder and rest of plumbing was installed ~3 years ago. It was filled with water and the first isolator closed. The pipe leading to that first isolator mostly drained though when the temporary feed was disconnected. The pipe was then capped and it has sat since with some water in. Below is a diagram of the pipework up to that closed level valve. The bottom most section of pipe (approx 3ft long) was probably half full of water.

 

Below the diagram are some photos of the inside of the pipe. It looks like that fist horizontal section has some crystals on the top of the inside and black. I got the endoscope up to the first elbow and looking up the first vertical section it looks like is is probably just a bit of blackening.

 

Questions:

1. Is the pipe OK? That first horizontal section looks a little pitted, but is it nothing to worry about?
2. Ideally I'd have a tee at the upper most 1ft horizontal to allow flushing the pipe back towards the brass inlet fitting. There's no movement in any of the pipework so cutting one in now would be tricky. A self cutting drain doesn't feel like a permanent fixture to me.
3. Is there a cleaner I could use for 'static' flushing.

 

I plan to pressure test the pipe with water at 10bar. That will force water 90% of the way up towards the Closed Valve. That would allow a near zero flow rate flush which is what I mean by a 'static' flush.

 

Note: No drinking water will be consumed through any of this pipe.

Note2: I couldn't be bothered to set the date on the endoscope but the images were today.

Note3: it's all 22mm pipe

 

 

 

 

 

 

 

Edited 5 hours ago by MortarThePoint

[Nickfromwales]

Metals fair better when fully immersed.

 

Standing water left behind that cannot vent off often promotes corrosion or oxidisation forming, so always best to fill the whole pipe run, purge it clear, and cap it off and leave it under pressure (eg fit the cap, and then open the valve and close it again to keep it full and under pressure). 

[MortarThePoint]

14 minutes ago, Nickfromwales said:

Metals fair better when fully immersed.

 

Standing water left behind that cannot vent off often promotes corrosion or oxidisation forming, so always best to fill the whole pipe run, purge it clear, and cap it off and leave it under pressure (eg fit the cap, and then open the valve and close it again to keep it full and under pressure). 

 

Makes sense. What would you do at this point though?