I wanted to share details of an electric underfloor heating repair which came about when the system stopped heating.
Loose wire underfloor heating
A “loose wire” system is suitable for odd shapes and small spaces. The manufacturer should give clearer instructions to prevent the problem, particularly as this appears to be a common installation fault. As it turned out, our electricians and specialist carried out the repair efficiently and professionally and you would never know there had been a fault; or a tile replaced.
Picture the scene – a brand new £16k bathroom fully tiled in porcelain – then the electric heating wire fails. Do you leave it (and ask for compensation) because you can’t bear to see your beautiful bathroom ripped apart; or do you get it fixed?
Wire had been laid in loops and taped into position in accordance with the instructions (see first image below); then the contractors spread levelling compound over the top. All OK so far.
The key oversight however was that the installers should not have taped over the joint between the hot and cold tails; instead of taping along the length here, they should have taped across the wire either side leaving the joint itself clear (see photo below). This is to allow the levelling compound to flow over the joint directly and so transfer heat from it efficiently. Otherwise, the joint becomes sealed in a “bubble” under the tape; with no mass to transfer the heat, the joint eventually burns out. The technician pointed out that the same problem could also arise at the far end of the installation where the two heating wires meet.
Electric underfloor heating repair
We asked our installers carry out the electric underfloor heating repair which they did without fuss. They had to call out a technician from the manufacturer who had the proper equipment. Initially, he pinpointed the fault by applying a very high voltage to the wires, forming an electric arc across the break. This showed up as a hot spot on an infra-red camera. We had taken photos throughout the bathroom renovation so the contractors could confirm that the location of the break was where the hot and cold tails joined. The specialist carefully smashed (!) the tile immediately above and performed the repair, before fitting a replacement tile with identical grout.
It now looks as good as new.
The technician said that he carries out several repairs a week mainly due to installation issues. The usual cause was where an installer joins the hot and cold tails in a stud wall where there is nothing of substance to transfer the heat. Heat transfer is clearly an issue and all installers should be aware of it. I hope this helps.
