Crosswater valve conundrum.

[Annker]

I have been driven up the wall trying to figure out how to connect pipework to a Crosswater Fusion concealed shower valve.

To my mind the installation instructions contradict themselves and I'd appreciate to hear a more qualified interpretation than my own (I'm a Carpenter not a Engineer of any description)

 

The valve has:

• G 3/4" (BSPP) female shower head port. There is no seat for a rubber seal to sit in this port (and none show on the diagram)
• G 3/4" (BSPP) male H&C inlet ports. Rubber edged gauze washer/filter are required to be installed on the ports 

 

The instruction specifically state:

• Make all pipe connections using a proprietary thread sealer
• Do not use tapered threaded adaptors

 

My understanding is that a female port (where a rubber seal and seat for that seal is absent) requires the mating male to be tapered thread (BSPT) and wrapped with thread sealer to make the joint; and where the male ports have a rubber edge filter provides the seal then using thread sealer (Locktight 55 cord for example) may hinder making the joint.

If that understanding is correct then the instruction are surely contradictory?

 

     

[Nickfromwales]

Can you post a pic of the ends of the hot and cold union please. 
 

For the shower outlet this is simple. 
 

This goes into the top. 
 

Then this goes into that. 

 

 

Likely 2 of these for hot & cold. 

 

 

 

The bush simply gets 21 turns of PTFE tape, same with the 1/2” male thread, or buy liquid PTFE like pipe superglue if you’re not confident.

 

Those 3/4” fittings should be just a bit over hand tight and a little pinch with a spanner and all good. 
 

Make off stubs of 15mm into them before mounting them onto the shower, so you’re not swinging off them and putting the rubber seals under undue stress / movement etc  

[SimonD]

19 hours ago, Annker said:

• Make all pipe connections using a proprietary thread sealer
• Do not use tapered threaded adaptors

There are circumstances where tapered thread fittings are not appropriate. Clearly this is one of them so follow the manufacturers instructions. I generally find Loctite 55 to be 100% reliable although surprisingly I've just done an installation where 2 of my radiator tails are seeping on pressure testing, but that's more down to unbranded rad tails with built in drain off that I needed in a hurry so took what was available off the shelf and manufacturing tolerances aren't great! 

[Annker]

Thanks @Nickfromwales and @SimonD for your replies.

So I had done a bit of research before you replied and what I gathered is that there are no hard and fast rules when it comes to mixing thread types, and valve manufacturers don't seem to follow any strict protocol either!

 

Basically the only certainly I could find was that fitting that you find on flexi type fittings, female 1/2" BSPP with rubber washer, shouldn't need any thread sealer, as Nicks says just watch that you don't over tighten and strip the washer.

 

What I found useful is that the best thing to do firstly, is dry thread fittings together to see what works.

I found that the tapered fittings I wanted to use, threaded into the female BSPP ports on the valve just fine, and certainly were not going to stress the port. In that instance wrapping them in Locktight 55 made a great seal.

 

My supply pipework is Hep2o so I wanted to adapt to that from the valve ports with as few fittings as possible.

These male and female couplers facilitated that so were my choice of fitting.

It was an effort to confirm the thread type on these fittings, I couldn't find it published anywhere by Hep2o, so I had to determine it myself in hand.

The males are BSPT but the female are BSSP, apparently that is typical of these type of fittings.

 

 

 

[Annker]

Below is my piping arrangement.

All bathrooms systems have been wet pressure tested and seems dry and holding pressure.

 

 

 

[Alan Ambrose]

Congrats, looks v tidy.

 

>>> My understanding is that a female port (where a rubber seal and seat for that seal is absent) requires the mating male to be tapered thread (BSPT) and wrapped with thread sealer to make the joint

 

I don't think that's right. My understanding is not to mix parallel and tapered unless you need a temporary bodge. I think most threads used in residential are parallel. Both parallel and tapered will need good thread sealer and I've used some cheap parts in the past that needed a bunch of thread sealer to work. That's all consistent with the instructions you quoted which said, in effect, 'don't use tapered parts here'.

[Annker]

1 hour ago, Alan Ambrose said:

Congrats, looks v tidy.

 

>>> My understanding is that a female port (where a rubber seal and seat for that seal is absent) requires the mating male to be tapered thread (BSPT) and wrapped with thread sealer to make the joint

 

I don't think that's right. My understanding is not to mix parallel and tapered unless you need a temporary bodge. I think most threads used in residential are parallel. Both parallel and tapered will need good thread sealer and I've used some cheap parts in the past that needed a bunch of thread sealer to work. That's all consistent with the instructions you quoted which said, in effect, 'don't use tapered parts here'.

Yeah I'm not 100% sure.

 

Both my AI's reckon fitting a male tapered into to female parallel is commonly done and acceptable practice, below may be nonsense but this is what it spat out when asked:

"The R-into-Rp arrangement is genuinely standard — that part is correct. A tapered male (BSPT/R) screwing into a parallel female (BSPP/Rp), sealed with PTFE or a thread sealant, is explicitly permitted under BS 21 / ISO 7-1 and is honestly the most common pressure-tight joint in UK domestic plumbing — most valves, boilers, and radiator tails are connected exactly this way. So mechanically, there's nothing wrong with that combination in general."

 

Admittably the instructions for the valve specifically said not to use tapered threads, however it also made a few contradictory statements.

 

In the end I could thread male tapered fittings entirely into the female parallel ports without any friction or stress; with the addition of Lock tight 55 these joints have passed 5.5 Bar wet pressure test and current not weeping. and will hopefully remain that way.

 

I always have in my head that the leak risk will be less where fewer joints are used, so yes these Hep2o couplers are tapered, but they get made straight onto Hep2o pipework so it's six of one...... 

 

 

Edited 3 hours ago by Annker