fittings for minidue leaking

[Jupiter01]

I've installed the minidue dosing device to help with water hardness and am up against some damn compression fittings again!

ive applied PTFE and LSX. I usually see a tiny bit of water emerge after several hours. I've now tighten as best as I can too. It does have a fibre washer in place - that it came with.

ive included some pics and am pointing to the problematic joint. This is affecting the top and bottom side.

I'd appreciate your expertise in this please.

 

[dilalio]

Can you not lose that female iron and put the copper tube with nut and olive straight into the first fitting on the unit?
If not then you’ll need to remake the joints with some new fibre washers - they swell when wet to make the seal and are not usually reusable when they’ve been disturbed.

 

[Jupiter01]

I've assumed the pipe can't go straight in there for some reason but you've got me there! Presumably, if that coupler has screwed on to that fitting, so should a nut with an olive? I thought the thread was different but that isn't making sense in the light of your question...

 

[Jupiter01]

this is how it comes

 

[terryplumb]

If I have correctly understood ,the leaking joint /s , are the threaded female iron to male thread of the fitting that came with the mini, that fitting looks like a tapered thread ,and the female iron possibly a parallel thread.you probably are not using enough PTFE tape. Is the fibre washer between the mini and the fitting supplied with it ,or elsewhere ?

 

[Jupiter01]

you are correct in your observation of the leaking joint. The fibre washer came with the minidue and squeezes between the male and female join.
I applied 10 wraps of PTFE tape along with LSX

 

[John D v2.0]

If it uses a fibre washer then you don't use PTFE, that's likely to stop you tightening it correctly. PTFE is for tapered threadjoints, fibre is for face joints.
However it looks like the fibre washer would be on the supplied joint and the leaking joint would be a tapered one therefore only use PTFE on that one.
For rad tails I use about 12 turns, make sure you use enough so it doesn't tighten up all the way as the PTFE should be making the seal

 

[Jupiter01]

okay...
without PTFE I can tighten most of that fitting by hand. Is that normal?

I could try replacing the fibre washer and re-attempting that if there is a consensus on this. I'm conscious that some of the other posts suggest applying more PTFE

 

[terryplumb]

The fibre washer should be between the mini and the first fitting ,which you have put PTFE tape on that you do NOT need. All threaded joints can be put together easily by hand ,without ptfe ,just like you can put a nut onto a bolt !! Its the PTFE that seals between the threads. You don't fit a fibre washer into the female iron ,if that's what you are doing ,is it ???

 

[Jupiter01]

here you go guys. I've pulled it apart and taken some pics. I assume its self explanatory.

I can't remove the reducer off the other fitting as I think it's been tightened too much...

am I best getting a single reducer which takes me from what I have on the minidue to the 22mm pipe?

 

[terryplumb]

Get rid of the PTFE that's on the threads of the mini. The fibre washer is all that you need to make a seal. I was under the impression that the leak was NOT on those ,but at the joint of the female iron , as indicated by your finger on the earlier pic ,the joint that you now say you can't take apart ?????.

 

[dilalio]

Try and lose the female iron as I said above... you should know immediately if it’ll take a nut and olive.

 

[terryplumb]

Pic at 12.19 dilalio .its not conical inside ,its flat faced .

 

[Jupiter01]

the leak is with the female coupler.
if I get shot of this, how will the 22mm pipe connect to the remaining fitting?

I think I need some form of female coupler/reducer?

I found a 1" to 22mm female coupler but the thread part was too deep which means I can't thread it fully on the minidue. I think I need one of these with a shallower thread section on the female part. Hope that makes sense

 

[terryplumb]

you are just not getting it at all. You have the most basic joints to make .the first seals with a fibre washer its a flat faced union.the next is two threads male / female and seals with PTFE tape ,and finally a compression /olive to the copper pipe. Identical on the other side of the mini. That's it in a nut shell.