Underfloor heating L-E problem

[Desaray]

Hi, ok I half dont want to ask this question as it doesnt sit right but Id like your opinions.
Installed a heating matt and after the tiles went down I did my final IR tests and there is now a problem between L-E at a reading of ~22ohms. The reading between L-N is still normal at 43ohms, correct value from the manufacturer. Now then what is going to be the main problem with me disconnecting the mat Earth from the main earth and letting it run like this? Problems i see are possible arcing causing further damage to the matt thus totally ruining it, possible electric shock but not sure as porcelain tiles arent known for there conductivity values.
Ideal situation is to rip the floor up and replace the matt but the tiler is denying its his fault and not going to pay for this, neither is the customer and im not also, so who foots the cost for this.
Anyone had this before?
Thanks

 

[Charlie_]

Whatever you do don't connect it up and don't leave it in a way that it can be livened up...
did you carry out an IR test prior to tiling?
who installed the mat?

 

[R G]

Did you forewarn the customer about what could happen , I would now tell them that you tested the mat as recommended by the manufacturer and noted the readings , and the reasons for it , You cannot disconnect the earth as you're suggesting , the earth is there as a return path for fault currents , and would be unsafe to do this , I assume it was a tiler who laid the floor tiles??

 

[Desaray]

Ok cool, thanks. I installed the matt, did an IR test after taking it out of the box still rolled up, then one after I laid it before the tiler got it.

 

[Tidy Max]

If you tested before and after i would say you were in the clear mate. Crap situation but not one that you have caused. Explain to the customer it was fine before tiling and now its not and you won't energise it until the reading is correct. Don't ever bodge a job ESPECIALLY not when it's not your fault!

 

[Desaray]

Yeah agreed, I do have it all written down so will return it to the customer and will hopefully get this resolved! Bugger when these nice simple jobs turn into nightmares!

 

[ImpededLoop]

Something I have done in the past is to get the customer to witness the readings before and after the floor is tiled.

I always return with a bit of trepidation before I carry out the post tiling tests.

As others have said, don't connect it up.

 

[telectrix]

second previous advice. tiler's buggered it. tiler pays. end of.

 

[Charlie_]

You could offer to carry out tests (at an agreed cost) to determine where the damage is and then repair that faulty section.

 

[ImpededLoop]

You could offer to carry out tests (at an agreed cost) to determine where the damage is and then repair that faulty section.

How would you be able to do that? Surely the underfloor mats are effectively sealed units.

 

[Geordie Spark]

second previous advice. tiler's buggered it. tiler pays. end of.

Geordie is in agreement with Tel.



arty::clap::17:

 

[Charlie_]

1. Estimate approximate position using a multi meter.
the value already given may indicate it is halfway.
2. The use of a TDR would determine location more accurately.
3. My favourite, would be to use a thermal imaging camera
Once the damaged section is found it may become obvious why it is damaged.
Special repair kits are available but all you need is good quality heat shrink..

 

[Anthony S]

If I was the tiler and being accused of damage to the matt, I would just say prove it ?

Lift the tiles and what ? you still couldn't prove the tiler done it. I've fitted a few and never once had a tiler damage one of them mats or single cables. Like I said in another post, takes some doing to damage it.

You have to prove when you laid it and it was not damaged then and you can't.

 

[marc8]

Hi all
you can get it repaired & also find the location of the fault, company comes out & they put a test unit on the Matt that they then trace out the floor showing fault location then up with that tile & fix the fault, not used this before but have had other sparks who have had the same problem think they went through Matt manufacturers. Also when install underfloor heating I test mat first then install a test unit I leave on until I come back just has open circuit on it & gives a tone if circuit is shorted.
Good luck ( cost they spoke about was £350) for fault finding

 

[Charlie_]

Resolution is the key word..
Do what you can whether its at your cost or theirs, a bad word travels faster than a good word..

Ive found a few damaged heat mats;
Screws from the toilet being screwed down.
Screws from the door threshold..
Staple gun damage from initial install..
Also found a couple that have had tiles dropped on them from tilers