Underfloor heating help!

[Wayne Gollop]

Hi there,

i had a job today where the customers underfloor heating stopped working.
i tested the mats and both were reading 32 ohms.
he had a spare controller stat so I changed it.
The stat sends 240v to the mats. But as it takes a while (he says it can take a good hour in his house) and with the could weather would probably be longer. So I left. (The customer is a friend)
he has just texted me saying that its still not working.

Any ideas??? What have I missed????

the only thing I can think of is the sensor?

Its puzzling me.

wayne

 

[telectrix]

you could use one set fairly low. takes a long time for it to rreact to ufh though. i consider ufh to be useful only to keep your feet warm in the bathroom on what would otherwiswe be cold tiles.

 

[Guitarist]

Ufh.... work of the devil... It's unnatural and wouldn't have been allowed in my day!

 

[telectrix]

nope. coal fires. back boilers are the dogs danglies for heating water.

 

[bartkusal]

Cool thanks for the help. It's a split load rcd board. I'm going there Friday so will let you know how it goes.

I am not sure which reg in BGB, but I think you are not allowed to work on bank holidays.

 

[Wayne Gollop]

I like the rayburners. Father in law has just put one in to do heating and hot water. Just need to connect it all up with the storage tank.

 

[telectrix]

I am not sure which reg in BGB, but I think you are not allowed to work on bank holidays.

that's OK we'll all have a day off and let the muslems work.

 

[Lee Marshall]

I hope so.
PICK was talking to the wholesaler and they said about a room only stat!!?? One that doesn't use the sensor in the floor. What's your views on these?

it would always be on wouldn't it? the air would never get to the desired temp :/

 

[La Poste]

If it is the sensor how would you fix this problem?
Would you have to rip the floor up?
I am asking because the lady up the road thinks her underfloor heating is not switching off properly and the room is overly warm.

 

[DPG]

I think some sensors are in tubes, but I'm no expert on this so wait for some definate advice from someone who know what they are talking about Daz

 

[Billythekid]

If it is the sensor how would you fix this problem?
Would you have to rip the floor up?
I am asking because the lady up the road thinks her underfloor heating is not switching off properly and the room is overly warm.

Unfortunately anything is possible . . . I've seen sensors in conduit, laid in tile adhesive, between tiles in grout, even behind the skirting board! Although to be fair (credit where credit is due), I've yet to see one coiled in the back of the state ;-)

 

[Dipzy]

Don't the manufacturers installation instructions advise where the sensor should be placed?

 

[La Poste]

Thanks fella's.

I will have a wander up the road and grab the installation manual if she still has one.

 

[Stroppy]

We always used to run the sensor down a length of 20mm flexible plastic conduit turning a 90 degree bend so the tip was about a foot away from the wall. Can't remember how we capped the end so the tile goo didn't get into the tube, but the sensor always was free to pull back out if need be. It seems madness to bury it forever.

 

[monkeyelectric]

But the sensor/floor is stone cold. So getting to 25 degrees is impossible. This is an old installation so I'm not sure where the sensor is located. (In the floor)
I've never done underfloor heating so this it's a learning curve for me.
What else could it be?

Have you measured the resistance? I think its for every degree celcius it is below 25 you add 400ohms to the value, so say its a 10k probe at 25 degrees then at 20 degrees it would be 12k, it could be a 12k or 15k probe but the same principle applies, thats what i've always gone on anyway

 

[monkeyelectric]

If it is the sensor how would you fix this problem?
Would you have to rip the floor up?
I am asking because the lady up the road thinks her underfloor heating is not switching off properly and the room is overly warm.

The sensor also has to match the thermostat too otherwise it will send it the wrong information so you need to measure the probe resistance and check what the thermostat needs