Leaking 15mm to 10mm internal reducer

[Sard]

i'm gonna have a go with applying some LSX, my instinct is that it's the bit that fits inside the TRV thats not sealed properly. I can't imagine every TRV manufacturer out there has a perfect mating with the reducer.

With respect to leaking radiator tails, should I apply LSX on top of a good few turns of PTFE, or LSX first then PTFE or no PTFE at all?

 

[Sard]

Just bumping the thread, to get the last bit of advice on the LSX application method

 

[Madrab]

The trouble with these reducers is that they seal at 4 points, not 2 as a normal compression coupler, 2 at the inner section at each end of the olive and the outer section at both ends of the reducer, so if they're leaking I'd tape at both places.

I take it soldering is not an option?

 

[Sard]

The trouble with these reducers is that they seal at 4 points, not 2 as a normal compression coupler, 2 at the inner section at each end of the olive and the outer section at both ends of the reducer, so if they're leaking I'd tape at both places.

I take it soldering is not an option?

Unfortunately not, all my rads have 10mm tee offs and as these rads are on outer walls, getting a 15mm pipe in between the drywall and block wall would be impossible without sinking into block work which I'm not keen on. I did consider converting the 10mm to 15mm closer to the TRV but again it would be a real ball ache due to limited space. A 15mm elbow would end up poking out the wall.

I think joint compound would be my best option, given the leaks are slow weeps rather than a consistent drip

 

[Madrab]

getting a 15mm pipe in between the drywall and block wall would be impossible without sinking into block work which I'm not keen on

Nope, not what I mean, the usual procedure would be to solder one of these

onto the end of the 10mm pipe and then the 15mm end of it fits into the valve, removing any need to use the reducers and gives you a native 15mm fit.

 

[Sard]

Nope, not what I mean, the usual procedure would be to solder one of these

onto the end of the 10mm pipe and then the 15mm end of it fits into the valve, removing any need to use the reducers and gives you a native 15mm fit.

ah ok, I hadnt thought of that method. Is there a risk of damaging the solder joint given the various stresses these pipes tend to go through when being detached and re-attached? Also would the fitting itself be strong enough to have an olive compressed onto it?

 

[terryplumb]

The soldered fitting reducer is infinitely more reliable than any compression type ,if properly soldered of course.

 

[Madrab]

Is there a risk of damaging the solder joint given the various stresses these pipes tend to go through when being detached and re-attached?

Nope, the weak point on any 10mm soft copper system is the 10mm pipe itself

Also would the fitting itself be strong enough to have an olive compressed onto it

Yes, again, it's far stronger than any 10mm soft copper and doesn't need a lot of effort to seal.

The reducers (snap and olive'd) are a well known weak point for weeps/leaks when they are disturbed. I've replaced countless numbers that have been bumped and banged, typically by the hoover, and then they leak

Soldered reducers, as long as they are soldered properly, are then considered to be part of the permanent pipework.

 

[Sard]

The soldered fitting reducer is infinitely more reliable than any compression type ,if properly soldered of course.

Nope, the weak point on any 10mm soft copper system is the 10mm pipe itself

Yes, again, it's far stronger than any 10mm soft copper and doesn't need a lot of effort to seal.

The reducers (snap and olive'd) are a well known weak point for weeps/leaks when they are disturbed. I've replaced countless numbers that have been bumped and banged, typically by the hoover, and then they leak

Soldered reducers, as long as they are soldered properly, are then considered to be part of the permanent pipework.

Gents, once again many thanks for your continued help. It is really appreciated.

Based on the advice above, I will forgo the joint sealing method with the brass reducers and solder on the 15mm to 10mm reducing couplers instead. Funnily enough, all my solders have held up across moving 6 rads to different locations including the addition of new flow & return tee offs at various places, so I'm happy to give this method a go.

 

[dilalio]

so I'm happy to give this method a go.

Not a method... Best practice.
Got a plumbing question?
Then best to take the advice of plumbers!

 

[Sard]

With respect to leaking radiator tails, should I apply LSX on top of a good few turns of PTFE, or LSX first then PTFE or no PTFE at all?

Sorry to be a pain, just looking for a last bit of advice on this ^

 

[kidgreen61]

Sorry to be a pain, just looking for a last bit of advice on this ^

Just wrap 15 turns of PTFE on the tail, job done

 

[Sard]

Just wrap 15 turns of PTFE on the tail, job done

I'd like to go belt & braces with some sealing compound, just need some guidance on the application technique

 

[denso13]

I'd like to go belt & braces with some sealing compound

Don't use PTFE along with compound, it is fine on its own.

 

[Sard]

Don't use PTFE along with compound, it is fine on its own.

Ah, even better. Thank you!