Thermo mixer - what does photo show is the problem?

[olfrog]

Hi all,

Have installed a thermostatic mixer valve (shower+bath) but it's leaking where the 3/4" male goes into the female (both hot and cold). I popped to plumbers merchant to see if i could get a fibre ring, but the guy said it could be cross-threaded.

When i got home to see, neither is cross threaded, it's just the male seems longer than the female? I have attached two photos. Note that you can see in the photo a 1mm gap.

• What do I do?
• Should i send the TMV back and say it cannot be fitted with a standard 3/4" male?
• Are there different sizes of male and i need to get a shallower one?
• I have put PTFE tape on it, but should i jam in a couple of fibre rings?

[Just as an extra, you can see that its a 15mm pipe going into a 22mm converter and then into a compression connected to the 3/4" - all connections are fine except the 3/4" join]

THANKS!!!!!

 

[Dannypipe]

Use Loctite 55 on the threads. That won't leak. Good luck.

 

[royston]

usally put PTFE around the olives not threads, carnt say ive had any problems that way.

 

[D.W.Bathrooms]

I could be wrong but just a feeling i have that there might not be enough ptfe on the male thread? thats just from looking at the photo so like i said i could be wrong. A good amount of ptfe, usually 15-20 wraps and either a jointing compound (water hawk?) or a silicone should cure this. you do sometimes get a small gap but the tape and sealant should stop any leaks. good luck

 

[fagsanbooz]

Some BSP threads are 'parallel' and some are 'tapered' and sometimes a parallel thread indicates a washer is required either at the point you have indicated (similar to an Immersion Heater connection) or at the base of the fitting so it seals against the base of the female thread. Some copper to irons also are available in different lengths. You should have some thread sealent (ptfe or similar) but this should be applied so that the raised part of the male threads are still evident but covered.

 

[Hankers]

I agree with DW bathrooms, I come across this quite often but as long as you have plenty of wraps of ptfe it should be fine.

 

[clivetheplumber]

Personally I would use boss blue & hemp, if your still aloud to use it over there😉

 

[tamz]

No matter what you end up using you should have used a bit wood to fix the valve to.

 

[Gray0689]

No matter what you end up using you should have used a bit wood to fix the valve to.

Screw holes not there for nothing not good if valve moves

 

[tamz]

Might be one of them floating valves

 

[Bartdude]

Is the shower wall made from MDF?? Could have problems there.

 

[olfrog]

Use Loctite 55 on the threads. That won't leak. Good luck.

yes, I have read up on this and I will do this next!

 

[olfrog]

usally put PTFE around the olives not threads, carnt say ive had any problems that way.

PTFE is for threads (and tucked over inside) but this joint has no olive as is not compression…[

 

[olfrog]

I could be wrong but just a feeling i have that there might not be enough ptfe on the male thread? thats just from looking at the photo so like i said i could be wrong. A good amount of ptfe, usually 15-20 wraps and either a jointing compound (water hawk?) or a silicone should cure this. you do sometimes get a small gap but the tape and sealant should stop any leaks. good luck

really? Wow, I only ever do 3x wrap around with PTFE. I guess that Loctite 55 is a version of the jointing compound…

 

[olfrog]

Some BSP threads are 'parallel' and some are 'tapered' and sometimes a parallel thread indicates a washer is required either at the point you have indicated (similar to an Immersion Heater connection) or at the base of the fitting so it seals against the base of the female thread. Some copper to irons also are available in different lengths. You should have some thread sealent (ptfe or similar) but this should be applied so that the raised part of the male threads are still evident but covered.

thanks, did not know this! Will check it out.

 

[olfrog]

Personally I would use boss blue & hemp, if your still aloud to use it over there😉

thanks Clive, will have a go with the Loctite 55 or Boss Blue depending on which I find..

 

[olfrog]

Screw holes not there for nothing not good if valve moves

hey, well spotted! Actually, it’s mounted on a 2x2 wooden pillar, but I had to take that out so I could get a nice photo 😉

 

[olfrog]

Is the shower wall made from MDF?? Could have problems there.

tell me more? It’s only 9mm and I will pva it and then tile it (on the other side). It’s mounted on a 2x2 frame.

 

[HoodedClaw]

Personally I use 22mm far eastern ply for exterior use and give that a coat of latex sealant.

I really hate when a leaking mixer has soaked the mdf, unprotected wood and its mouldy/rotten.

 

[Bartdude]

tell me more? It’s only 9mm and I will pva it and then tile it (on the other side). It’s mounted on a 2x2 frame.

When the MDF gets damp it will swell and disentegrate,it's no good for building a shower with. You shouldn't apply PVA and then tile either,the PVA stops the adhesive bonding properly.Check the tiling forum for more info on this,it's discussed at length!