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

 

[monkeyelectric]

Have you tested the sensor?

 

[Guitarist]

You need to clamp the feed to know for sure.

 

[Wayne Gollop]

Have you tested the sensor?

No I haven't. What readings would I be looking for?
I guess putting a clamp meter on the feed in looking to see if its pulling a load.

 

[BMelectrics]

have you tried an I/R Test across the power o the mat? L-E AND N-E??

Could be a break?

 

[monkeyelectric]

No I haven't. What readings would I be looking for?
I guess putting a clamp meter on the feed in looking to see if its pulling a load.

It will either be 10k, 12k or 15k @ 25 degrees depending on the sensor

 

[Wayne Gollop]

It will either be 10k, 12k or 15k @ 25 degrees depending on the sensor

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?

 

[telectrix]

in the stat., temporarily put the element ends directly to the L and N. if it heats up then or shows current draw on your clamp meter, , it's either the stat ot the sensor.

 

[stuartcourt]

Go with above also Has it ever tripped

 

[Wayne Gollop]

in the stat., temporarily put the element ends directly to the L and N. if it heats up then or shows current draw on your clamp meter, , it's either the stat ot the sensor.

The stat has been changed and its sending 240v to the mats(but I haven't clamped it) I have a spare sensor so I was going to connect that in temporarily to see if it works. Other than that all I can think of is the mats are knackered. But why would I get 32 ohms on both?? That tells me they are ok?! Or aren't they!! Lol

 

[Wayne Gollop]

Go with above also Has it ever tripped

No not that I'm aware.

 

[telectrix]

32Ω suggests that the mats are OK. if they are on a RCD protected circuit, that rules out short to E. try the spare sensor in the stat.the mats shoud each draw about 7A, reducing as they warm up.

 

[Wayne Gollop]

32Ω suggests that the mats are OK. if they are on a RCD protected circuit, that rules out short to E. try the spare sensor in the stat.the mats shoud each draw about 7A, reducing as they warm up.

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.

 

[telectrix]

keep us posted. bet it's the sensor.

 

[Wayne Gollop]

keep us posted. bet it's the sensor.

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?