What are there two connectors

[Derekq]

In the process of fitting new taps to kitchen sink, hot water was straight forward and working, then looked at the cold supply and found these two connectors, the lower one has the 15mm pipe with usual nut but just above it is another nut !!! does anyone know what it is and whats it for.
Thanks for any info.

 

[ShaunCorbs]

Female iron onto the tap

and a normal compression set up below

 

[Derekq]

Female iron onto the tap

and a normal compression set up below

Thanks for info, is there any reason you can think off for this being done and why the compression fitting isn't straight onto the tap, is there any purpose for the female connector.
To free the tap I would need to undo both of these connectors is this correct, Thanks.

 

[steadyon]

1. Probably the threaded shank of the tap was shorter than that which was there before it, so female iron used as an extension.
2. Yes, to free the tap you would need to:
2a. Undo the tap connector compression nut (lowest hexagon).
2b. Remove the iron (still called an iron even though its brass) by undoing the middle (brass) hexagon.
2c. Remove the back nut - black plastic nut.
3. When fitting new tap:
3a. If it comes with a plastic back nut, worth replacing with a brass back nut. Less likely to split and gives better grip on tap.
3b. If the shank is too short to reach the tap you may need to re-use the iron.
3c. If you have to use the iron, you will almost certainly need to use PTFE tap, Loctite 55 or a liquid sealant like Loctite 577 or Flomasta Pipe Seal to seal the iron to the threaded tap shank.
3d. Get a new fibre washer (1/2" tap connector washer) for the tap connector.

 

[Derekq]

1. Probably the threaded shank of the tap was shorter than that which was there before it, so female iron used as an extension.
2. Yes, to free the tap you would need to:
2a. Undo the tap connector compression nut (lowest hexagon).
2b. Remove the iron (still called an iron even though its brass) by undoing the middle (brass) hexagon.
2c. Remove the back nut - black plastic nut.
3. When fitting new tap:
3a. If it comes with a plastic back nut, worth replacing with a brass back nut. Less likely to split and gives better grip on tap.
3b. If the shank is too short to reach the tap you may need to re-use the iron.
3c. If you have to use the iron, you will almost certainly need to use PTFE tap, Loctite 55 or a liquid sealant like Loctite 577 or Flomasta Pipe Seal to seal the iron to the threaded tap shank.
3d. Get a new fibre washer (1/2" tap connector washer) for the tap connector.

Hi
Thank you or the detailed info, yes maybe for some odd reason the 15mm pipe was to short to meet the tap thread very odd but I will be sure to use some ptfe or sealant when putting the new tap in, thanks again for the good info.