Connecting to a "washing machine" inlet

[Christian McArdle]

My new water softener came with basically washing machine style hoses which will be useless for my high flow system.

Now, how would I connect fixed pipework to the fixings? The outlet/inlet is a plastic 3/4" male thread. Should I be using a 3/4" tap connector, 3/4" female iron and PTFE or something else?

Christian.

[Set Square]

A tap connector should be fine. The threads will be parallel, and will need a washer to seal - as opposed to sealing on tapered threads. You may need to dress the ends of the plastic fittings to ensure there are no burrs and/or use rubber washers rather than the usual fibre washers normally used with tap connectors.

If you need a degree of flexibility, you could use something like BES item:

13753 [Go to and then navigate to it - direct URLs don't seem possible on the BES site!] This is a braided hose with a 3/4" BSP tap connector one end, a 19mm bore, and a 22mm compression fitting at the other end. [I've got some of these on my bath taps - but make sure you order the washers separately - they don't come automatically!]

[sPoNiX]

I recon some of those braided hoses would work fine.

sponix

[Christian McArdle]

I need full bore, though, really. The entire house, hot and cold is mains pressure. I'd prefer to do the pipework in flowed 22mm pipe.

Christian.

[Christian McArdle]

Tap connector it is, then!

19mm isn't a bad bore, but I think I'll stick with the full 22mm. I want every last litre per minute out of it. Whilst my pressure is reasonable, it isn't brilliant, as I'm on top of a hill. The softener itself is going to lose me over 1 bar.

Christian.

[Set Square]

Another thought: Tap connectors usually have a shoulder or spigot on which the washer sits, and which is intended to go inside the tap tail. I have somethines found with plastic fittings - particularly on toilet cisterns - that the spigot *won't* go into the fitting, and needs to be filed back to less than the thickness of the washer in order to get a seal.

[Christian McArdle]

Yes. Presumably the plastic pipe is too thick. Shall I just go for a 3/4" iron and seal it? One of the main disadvantages of the tap connector is the much reduced bore through the middle, so a standard iron fitting should allow more flow.

Obviously with non-tapered threads, you just need to know when to stop, but it should seal fine against plastic with PTFE shouldn't it?

Christian.

[sPoNiX]

I'm thinking something like screwfix item 52117.

I used something similar to connect up my bath taps and have had no problems.

Ther are available withvarious fittings on the end from B&Q, plumbers merchants etc.

sponix

[Christian McArdle]

Nah. I'm running the entire house's water supply through it. Screwfix 52117 wouldn't have remotely enough flow rate through it. The 19mm bore one someone else suggested is actually quite tempting given that it is presumably inside diameter and so is really not far off that of 22mm copper. However, a smooth bored flowed bend 22mm copper setup seems more reliable to my mind.

Christian.

[Set Square]

You could use one of these:

tape isn't really any good on parallel threads - you need to seal on a

*face*. In this case, a rubber washer of suitable thickness would be best. It may need to be quite fat if the FI fitting has got a lot more thread than your plastic softener.

[Pete C]

Using:

30cm of 19mm pipe at 30 lpm gives 0.00577 bar pressure drop 30cm of 22mm pipe at 30 lpm gives 0.00285 bar pressure drop

So there's about 0.00292 bar or 0.042psi in it.

So a good case for using 22mm pipe over long runs but a short run of

19mm shouldn't hurt.

I'd expect the flexis from BES aren't shouldered.

cheers, Pete.

[Martyn Pollard]

I would go with the hose solution. Some manufacturers sell high flow hoses, so try calling Waterside and a few of the others.

Don't forget you need a drinkable supply that is not softened.

Martyn