Electric underfloor heating issue

31 Dec 2015
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United Kingdom
Hi there

Got a problem with my electric underfloor heating that my builder installed in 2013

It's a Heat Mat installation below tiles, controlled via a KNX switch that turns it on for a set amount of time (via a KNX actuator). It's in the bathroom but there doesn't seem to be any cracks in the grouting etc where water could have got through.

So when I turn on this specific EUFH circuit it now it trips the RCD. All the other EUFH circuits on the same KNX actuator work fine.

I did have the EUFH in another room fail about two years ago, but in that case the floor didn't heat up, and it didn't trigger the RCD (the engineer found a break in the mat heating wire and repaired it).

Does this issue sound like it's a faulty mat again or is there something else that I should double check before calling Heat Mat and digging up tiles? Fuse spur fuse is fine. Thanks
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ok cool thought as much, thanks

what a headache... next time wet underfloor heating system!
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