Underfloor heating problem

[Mungo "two sheds" Toadfoot]

A family member has Wickes underfloor heating under a ceramic-tiled floor and it has ceased to function.

There's power to the fused switch and the 3A fuse is ok, power then goes to the thermostat but I can't test it any further because the cable's in a cavity.

The thermostat has a PCB in the detachable front panel but it doesn't look, or smell, burnt. Any ideas how to test the panel on its own to see if it's working? Is the next thing to try a continuity test on the heating cable from the thermostat to rule out a (somehow) failed wire under the floor?

I only understand 'letrics up to a point and then it all becomes wizardry AFAIC :)

Si

[That Bloke]

Switch all power off from the mains

Check you have switched it off

If possible pull out the suppliers fuse, against the regs but who cares if it was broken by the last electricity board bloke who was there last year.

Check you have done all that again.

Disconnect the heating element from the controller and put an ohm meter on the tails from the element and it should read say 50 to 250 ohms. If so it is ok, if very high say over 500 ohms report your reading back, if no reading then it is faulty.

I assume it is a thermostat in the control unit rather than one under the tiles that is connected to the control unit. The best way to test it is to connect the tails of the element to the feed to the control unit thereby bypassing the unit.

If the floor heats up the unit is faulty. Unless that is the instructions for the unit are just too difficult to understand which they can be if they are not written clearly.

[Rembrandt Kuipers]

Just in case nobody more knowledgeable than I mentions it: You should not need to damage the floor to find out where the heating element is broken (if it is). Using a buried cable detector you should be able to trace the course of the cable (while on) to the point it is broken.

Hopefully this means you only have to break one tile to fix it, if that is the problem. Make sure you know how to do the fix first though, you are not meant to make joins in these cables; there might be more to it than fixing a broken flex (for example). (Ask Wickes how?)

I hope that helps.

Rem

[Mungo "two sheds" Toadfoot]

I'll have a play later today. I understand a fair bit about 'lectrics but I do thank you for your concern and for the sensible safety advice.

That's what I needed to know, ta.

Yes. Aren't new ones expensive?! Around £50.

I'll try that if it looks like the element's ok.

That'll be the next step when I discover that it *should* be working but still isn't ('letric gremlins at work)

Thanks again,

Si