The underfloor heating isn’t working in the downstairs bathroom. This is of course a fully tiled bathroom with the heating element laid into the tile cement. I am seeing two possible faults, the controller or the heating element so my first thought is to identify which one it is. Hopefully the controller otherwise I think we need to re-tile the room.

My plan for the morning is to bypass the controller and just run the mains into the heater element. If the floor starts to heat then we disconnect and assume it is the controller that is faulty.

Anything wrong with that plan? I have a multi meter if that helps anything.

Can you not just use the meter to check the continuity of the element? Surely the only thing that can go wrong with the element is a break? I wouldn’t want to whop the mains through it personally…

Get someone in who knows what they are doing.

Get someone in who knows what they are doing.

What’s the fun in that?

Can you video it? Connect to the mains then pour water over the floor to a depth of 1cm with no shoes on – that should tell you if it’s working 😀

We had a tiller in to look at why all the tiles were lifting and in the kitchen. Short story he lifted a tile to see where the failure was and took a chunk out the element. Ffs! He had a company come from Essex to Bristol to sort it out. No idea what the cost was but it wasn’t cheap. The guy came on a Sunday morning and was flat out all week. It wasn’t that easy to repair, our sparky mate was not interested in doing it, it’s a specialist repair job. No problem with heating since repair. Tiles are still sh;)£ though.

Get someone in who knows what they are doing.

I have STW to help me know what to do.

Can you not just use the meter to check the continuity of the element?
It was the multi-meter thread that reminded me that I had one and yes, I will probably use that.

Connect to the mains then pour water over the floor to a depth of 1cm with no shoes on – that should tell you if it’s working
That would be like the time I turned off the power to the garage while I was with the garden pond trying to fix the electrics the pump and my daughter turned the power back on. 240V for about 30 seconds before I could actually explain that I wanted her to turn the power off again. Such fun.

I now understand your name on here…..!!!

When I did ours I read that the temp sensors can go and it was recommend to fit two with the second not wired up.

I also used conduit under the tiles to the door and then in a covered channel in the wall so if both fail I should be able to fit a third.

You might get lucky and when it was fitted the above was done…

Apparently it’s very rare for a fault with the heating wire, after all it’s a bit of wire not much to go wrong unless disturbed

Check if you controller can work off air temp and not just floor temp in the settings. See if you can get it working that way, that may prove it’s the floor temp sensor

DT78 – The wire was definitely just sunk into the adhesive as I remember saying to the guy who did it that it didn’t look very maintainable but it was an insurance repair and he said He was paid by the hour so I could fikcung talk to the company for all he cared.

Glad to hear the heating wire is a rare fault and still hoping for a controller. The controller is actually mounted outside of the bathroom and under the stairs so I assume it is not a normal air temp thermostat. It has been fine for the last 7 years with the floor warm when we want it and not when we don’t. We haven’t adjusted it since it was fitted because of this lot in the way

If you’re happy to, then test the controller first by putting a multimeter across the output connections and turn the temperature up…. You should get 240v on the meter.
If you’re not then the controller needs replacing.

If you do get 240v then this…

Can you not just use the meter to check the continuity of the element?

And if the controller is digital then it should be showing the current floor temperature…. In which case the sensor is fine.
(The controller would probably show an error if it wasn’t getting a sensor signal anyway).

We had a problem with warmup underfloor heating. Turned out the contractor had poorly installed it and had left the ends of the cabling uncovered by tile and adhesive which burnt them out. The warmup guy had equipment to put a current through and identify the exact location of a break in the floor meaning one tile up rather than the whole floor.

My parents UK UFH thermostats are garbage. Not one has an operable screen anymore.
Anyway, if you don’t fancy measuring 240v and with your “history” you probably shouldn’t deal with anything live. So measuring the resistance range of your thermostat or indeed setting your thermostat to ambient heat vs floor heat would be a start.
I set 2 or 3 thermostats per floor for redundancy.
Presumably have a GFCI in your heating circuit so any broken heat cables would trip that.

Anyway, if you don’t fancy measuring 240v and with your “history” you probably shouldn’t deal with anything live. So measuring the resistance range of your thermostat or indeed setting your thermostat to ambient heat vs floor heat would be a start

Except he’s got to access the back of the thermostat to get to that cable anyway!
💥

That would be like the time I turned off the power to the garage while I was with the garden pond trying to fix the electrics the pump and my daughter turned the power back on

That was the one good thing about old fuse boards, remove the fuse and put it in your pocket while you worked so no one could come along and switch it back on.

I’ve just been through this. Our underfloor stopped working, thermostat was showing it trying to heat but floor was stone cold. Checked the continuity of the mat and seemd to indicate continutiy but an earth fault. Replaced thermostat which then popped the circuit when it demanded heat. Got a co. from Cheshire I think to come – they ram a current into it then use a thermal imaging camera to find the problem. Smashed out the tile and dug out the cable to find it had been nicked on installation and some tape put round it (fckn builders!), it had eventually burnt out. They cut that section out and sealed it all up. Works better than ever now and pretty simple albeit a painful 300 quid to fix !!

My brother had his fail
Idiot builders failed to follow installation instructions and left too wide gaps so had 3mtr of spare element at the end
Rather than tape it 5cm apart they coiled it.
So it melted through itself
And these guys charge xxx a day to be stupid
Sds and cranked 75mm chisel will sort it. SDS drills sort most things, like the 6mtr trench down the middle of my drive
Because shit builders built the soakaway 50cm from the footings
Whicj i am now going to lay 110mm soil pipe to a gravel pit

Ours went at the thermostat buried under the tiles. We simply swapped it for a timed switch which turns it on for X minutes every 30mins. With a bit of playing we worked out the right number of minutes for a stable background heat over the cold months. (We just turn it off in summer)

Sherlock Holmes would know the answer.

Well I have tested the resistance as per this useful video : https://www.youtube.com/watch?v=DDyR3Dy6DdU&ab_channel=Underfloorheatinghq

We have a reading of between 0 and 0.01 which suggests to me it is failed. The heating wire was part of a mat that was laid beneath the tiles and without a heat video it will be a challenge to find.

The good news is that we don’t like the floor tiles anyway and were thinking of changing them anyway (we were? since when? no-one mentioned this to me before) and it is only a small bathroom. The floor tiles go under the wall tiles so are going to be a git to lift without damaging anything. Look out for How to threads on tiling. 🙁

Well depending on the height of the first course of wall tiles, you might get away with using the floor tile, for a kind of skirting board type look. See it a few times looks okay if it’s not too high. It’s my plan if I have to replace our floor

we were? since when? no-one mentioned this to me before

You getting cold feet about tackling this?

Because shit builders built the soakaway 50cm from the footings

Building control would never of signed off on that. Your shit builders may of left you many other surprises if they think that’s OK

Hi, I rejigged it so we had independent heat no longer provided through the floor and isolation on the pipes so I can put up a false ceiling with insulation.

Three of these for other reasons

Thanks all