Ufh advice needed

[richarddeane]

Dear All, moved into an old house last year and one room is heated by electric Ufh which doesn’t work, it’s a large room about 25sq m and uses a devireg 550 wired through a contactor I assume due to the large load? I have tested the heating cable (we have some paperwork to suggest it is devi cable fitted) and the resistance is coming out at around 15 ohms but if i bypass the thermostat and wire direct thru the contactor it simply trips the main circuit board. Do you think it’s knackered or should I be testing anything else?

 

[Murdoch]

Unless you have proper test kit and competence to use it we will all be guessing.

get a spark in to test it properly is my advice

 

[ProDave]

"old house" and "electric resistance UFH" rings alarm bells as probably very inefficient (do you KNOW there is adequate under floor insulation for instance)

If "it trips the main circuit board" means it trips the RCD then there is very likely a fault with the heating mat.

Time for a complete re think of your heating system.

 

[richarddeane]

Thanks for replies so far, does 15 ohm resistance sound way out for such a large area? I have no specs to go on as this was fitted in 2006 albeit to a modern extension.

 

[SPECIAL LOCATION]

Thanks for replies so far, does 15 ohm resistance sound way out for such a large area? I have no specs to go on as this was fitted in 2006 albeit to a modern extension.

Pure guess work from limited info given...
so without further details I will repeat what Murdoch said earlier..

Unless you have proper test kit and competence to use it we will all be guessing.

get a spark in to test it properly is my advice

Plus you don't actually say what is tripping? MCB, RCD, RCBO??
Which would all make a difference when trying to work out the actual cause?

 

[sirsparkabit]

just a rough guide to resistance readings from the program site .