Sensor cable and electric ufh

[CC45]

Looking for some guidance regarding the sensor cable for electric ufh in bathroom.

 

I'd like to run it in a duct of some sort to allow replacement if it fails but I'm concerned about how much this will affect tiling and the height of the finished floor  (timber floor upstairs).

 

Its been suggested that I run it down then under the floor and then bring it up from below and leave it under a tile.  If it fails then forget it and just run the eufh for short periods of time.

 

Any suggestions? Thanks

Edited March 18, 2018 by CC45
Correction

[Barney12]

Funnily enough I’m doing that exact job this morning. 

 

I always run them in conduit (it always comes with the probe in my experience). I have actually had one fail in the past but it was within a couple of weeks of fitting. 

 

I simply cut the floor with the multi tool by 5-10mm so that the conduit sits down level with the heating element.

[Nickfromwales]

For pennies run a second spare one and sleep easy. 

Router / multi tool / then chisel for the main cut, and then sink the conduit 10mm and tile over. The Ufh wire will raise you by at least 3-4mm so you'll be another 2-3mm above that by the time you've tiled. . These don't really fail tbh if you've been careful with them during the install. 

Having a multimeter connected whilst laying the mat / wire is essential. The benchmark book that comes with it gives you the ohms @20oC vs the size ( watts ) of the mat your laying so you don't need to be electronically minded to set it up. Most auto-range so just connect the multimeter black wire to the blue wire of the cold tail of the mat, and red to the brown tail, and select ohms. You just keep checking that as you lay the mat. It'll change as your tiling due to the temp shift, but not much. 

Take ( record ) a reading when you take the mat out of the box, take it again at the halfway point, and again at the end of laying the mat. You need to write these in the back of the book to comply with the warranty. Do these again during laying the tiles, as that's when your most likely to damage the wire as you'll be using tile trowels etc. 

Once the mat is down,  go around the areas you've no mat and bulk them up with a self leveller. Leave that go off, about 4 hours for a good one. Then, optional, use a rubber edged grout float to smother a bedding coat of flexible tile adhesive over the wire / mat to bring the adhesive just shy of the top of the wire / mat to bulk the whole floor area up prior to tiling. Leave that go off and then the floor will be much easier to lay. Having to bulk out as your laying means more mixing and longer open times for the adhesive.

Prepping  the floor before you lay the tiles is the far easier option IMO and makes the job a breeze. "Less stressed is best" . 

[PeterW]

3 hours ago, Nickfromwales said:

Once the mat is down,  go around the areas you've no mat and bulk them up with a self leveller.

 

TBH I just use self leveller everywhere and pour over the mat when it’s down and bring it just above the wires and there is a perfectly flat and easy surface to lay tiles on. I’ve also taken to staples to hold down the mat at the edges as despite a lot being self adhesive they do move a little and it means you can get them taught and flat and they don’t lift when you pour the SLC. 

[Nickfromwales]

2 hours ago, PeterW said:

 

TBH I just use self leveller everywhere and pour over the mat when it’s down and bring it just above the wires and there is a perfectly flat and easy surface to lay tiles on. I’ve also taken to staples to hold down the mat at the edges as despite a lot being self adhesive they do move a little and it means you can get them taught and flat and they don’t lift when you pour the SLC. 

You can, but I find a much stiffer mix of standard ( eg not rapid ) set tile adhesive holds the dog ears of the UTH wire / mat down whereas with SLC you have to be crazy careful not to allow any single part of mat / wire lift. 

Using staples would instantly void most warranties. . 

Edited March 18, 2018 by Nickfromwales
Poxy iPhone !

[PeterW]

2 hours ago, Nickfromwales said:

Using staples would instantly void most warranties.

 

Through the mesh, not the wires .....

Nothing in the MIs about that I can see ..?!

[Nickfromwales]

43 minutes ago, PeterW said:

 

Through the mesh, not the wires .....

Nothing in the MIs about that I can see ..?!

Ok, you got me on a technicality. 

BUT....you lose the point anyhoo because you should have said so in that post . Joe public could have easily read that as staple the wire down, but don't beat yourself up over it, allow me to do it for you instead

 

[joe90]

4 hours ago, PeterW said:

 

TBH I just use self leveller everywhere and pour over the mat when it’s down and bring it just above the wires and there is a perfectly flat and easy surface to lay tiles on. I’ve also taken to staples to hold down the mat at the edges as despite a lot being self adhesive they do move a little and it means you can get them taught and flat and they don’t lift when you pour the SLC. 

 

Spooky, this is exactly what I have done ( yes staples through the mesh/mat ?) on the subject of probe, I ran ( and was supplied with) small flexible conduit which I ran from the programmer, brought it up through the wooden floor and taped over the end so the probe can be withdrawn and replaced if it fails.

[PeterW]

So that is me and @joe90 agreeing on the way to do it and I could always use my Jedi admin powers to make you agree too @Nickfromwales.....

 

But yes people, you staple the mat not the cable ....

[Nickfromwales]

1 minute ago, PeterW said:

So that is me and @joe90 agreeing on the way to do it and I could always use my Jedi admin powers to make you agree too @Nickfromwales.....

 

But yes people, you staple the mat not the cable ....

With great power comes.......great fear. 

 

[Barney12]

I really don’t like the mats, loose wire every time for me. You can get it exactly where you want it and tape it down well.

Then self leveller over the top. 

 

Much tidier (done today):

 

Edited March 18, 2018 by Barney12

[Jeremy Harris]

+1 @Barney12, I fitted the wires when I did the floor in our old bathroom.  Much easier to get them where you want them.  My only regret is not thinking of fitting them for comfort heating in our shower room, just to take the chill of the travertine.

[CC45]

Great help here - thanks to you all.  I think I will stick to a mat - as a first timer it would seem sensible.  Will get the router out to make a trench for the sensor and I like the suggestion of a second sensor just in case.  I assume you all tile first then protect the tiles and then skim the walls?  If the mat doesnt come with duct - what do you all use?

 

Had a slow day, bit of plaster boarding and then a few hours pressure testing the newly installed shower valve - why do these jobs take so long?

[Nickfromwales]

Off cut of 15mm pushfit pipe will do just not as easy to get a tight bend.