Underfloor heating has stopped working

Discussion in 'Electrics UK' started by aic, 8 Oct 2011.

  1. aic

    aic

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    I have electric underfloor heating. has worked well for last 4 years. it uses a Aube TH132 f control module. It appears to be working but the floor isnt heating up. I have repowered the unit after disconnecting for 2 hours. Nothing obviously wrong, but the floor isnt walming up. Any suggestions greatlfully recieved
     
  2. Taylortwocities

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    Do you have a multimeter, or a 2-probe voltage indicator (NOT a neon screwdriver).

    First thing is to check if mains voltage is getting to the input terminals of the controller. If NO then you need to find out why. If YES then...... use the ohms range on your meter and check if the floor element resistance and probe resistance are the same as when the flooring was installed (values should have been written on the instructions).

    If all OK then its likely that the controller is not working.
     
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  3. ricicle

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    To echo TTC's advice above :-

    -Check mains to controller (L+N)
    -Check output from controller. No output when there should be would indicate faulty relay/driver.
    -Check resistance of element 1000w = 53 Ω approx. (other wattages can be worked out from that)
     
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  4. ericmark

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    I have had problems with my mothers. Normally find fault with thermostat now one her third. I test with a clamp on ammeter as it shows without delay when it starts to work. After the third thermostat went we gave up. Bit hopeless anyway. It takes a good half hour to heat up and once we turn the shower on it's cold again the idea was to dry floor but my mother has finished well before floor is dry.
     
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  5. Taylortwocities

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    The probe resistance will vary depending on temperature. Expect it to be about 14KΩ at 20°C.
     
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  6. aic

    aic

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    many thanks, I will try these tests! :)
     
  7. aic

    aic

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    have replaced controller, have tested temp sensor. All working. powers on and off ok. But floor still not heating up. resistance of floor element is 13 kohms which i think is ok. so im completely foxed. manual makes reference to possible need of a snubber, which isnt present at present but cant see why this would help with this problem. help!!!!!!!!
     
  8. Taylortwocities

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    Well, I am afraid it isnt.

    Per the above

    How big is the mat? You should be seeing less than 300Ω on the resistance of the floor element.
     
  9. JohnW2

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    You don't really mean the element, do you? If you did, 13 kΩ would result in only about 4 watts of heating, which is pretty close to 'not working'!!

    Kind Regards, John.
     
  10. aic

    aic

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    Thanks for the information, as you can tell, home electrics isnt my forte/ However i have remeasured across the load part of the circuit it and its about 4 kohms (power off). The heating mat area is 35m2 (large kitchen area). Am I right in thinking that its the element in the floor that isnt working?
     
  11. JohnW2

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    I'm afraid that's how it's looking.

    Kind Regards, John.
     
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  12. aic

    aic

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    thank you all for the information It looks like a very expensive job coming up. I wonder why it stopped working though?
     
  13. JohnW2

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    Well, it's in the nature of electrical heating elements that they don't last for ever, which is why I would personally be very nervous (to put it lightly) about having any such system. I don't suppose it camne with a 'long-term' warranty, did it?

    Kind Regards, John.
     

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