Underfloor heating fault ! Need tracker / tracer not TDR ??

[Soulsurfer]

As above I need to track down a fault on underfloor heating electric mat or loose cable system as to get a guy to come and find fault area from u.k. is around £2,000 apparently and repair etc.. I'm almost certain that it's going to be a joint on the cold tails but any kit that could be used to locate the area advice wise would be great. Thought TDR but that won't really be the item for a short distance etc.. and only have a good mft, multimeters, oscillators etc.. apparently there is some instrument that pumps 1KV down and a sound sensor that can be used to hear the arcing where the fault is ?
Any ideas appreciated as voltage present but no current draw or continuity. Thanks.

 

[Richard Burns]

Depending on how deep the mat is then a cheap and cheerful tone tracer should work, attach the tone generator to the core and run the tracer along the cable route until the tone cannot be picked up, approximately there is your fault.
However the cheap (£20) ones only trace to about 2-3cm deep.

 

[Soulsurfer]

Depending on how deep the mat is then a cheap and cheerful tone tracer should work, attach the tone generator to the core and run the tracer along the cable route until the tone cannot be picked up, approximately there is your fault.
However the cheap (£20) ones only trace to about 2-3cm deep.

Thanks Richard, I have a rather expensive set from teaching fibre installs and copper comms while working for Jersey Telecoms a while back but not sure if will go far enough as this is apparently quite deep into screed. Nexans solid core cables.

 

[Richard Burns]

OK mains power signal tracers/ fuse finders again not very deep but deeper than the battery ones.
otherwise you are on CAT and genny scanning, which seems a little OTT for underfloor heating but cheaper than £2000.

 

[Soulsurfer]

OK mains power signal tracers/ fuse finders again not very deep but deeper than the battery ones.
otherwise you are on CAT and genny scanning, which seems a little OTT for underfloor heating but cheaper than £2000.

Ok sound, used to use Cat and Genny on the fibre installs to check u/g cabling routes etc.. for the civils to dig. Apparently this guy from mainland has a tool to locate right down to an area size of a 10p piece but I've never heard of such a thing.

 

[PEG]

Hi bud,have you IR tested the heating wire,at different voltages,to determine the ease of this arcing?
If you generated this arc,at a known frequency,he may be detecting this.
Or you could "clear" this,with some HV shananagins,and have it live,one side...but it's starting to get a bit shady

What makes you suspect the cold tails?

 

[Soulsurfer]

Hi bud,have you IR tested the heating wire,at different voltages,to determine the ease of this arcing?
If you generated this arc,at a known frequency,he may be detecting this.
Or you could "clear" this,with some HV shananagins,and have it live,one side...but it's starting to get a bit shady

What makes you suspect the cold tails?

Neighbour had a big flood and another company was called in on the insurance to sort it and apparently neighbour told my friend today that the joint against the wall where black tubing was and jointed with a squeezy tool into like barrel looking connectors fixed his ! I'm guessing it was crimped as spark told him it was badly corroded and breaking there.

I did IR at 250 and 500V and was low. No arcing just apparently a tool / instrument the repair companies have but I can't seem to find much online for sale..

 

[PEG]

There are always ways,and means

Not a time or place for trade secrets (not that anyone cares)

Google up the standard loop tests,messrs Blavier,Varley,Murray and Fisher.

It may give you an idea

 

[Soulsurfer]

There are always ways,and means

Not a time or place for trade secrets (not that anyone cares)

Google up the standard loop tests,messrs Blavier,Varley,Murray and Fisher.

It may give you an idea

Thanks bud, confused now though

 

[PEG]

This is an issue,like genital warts. Nobody admits it's a problem,and if you find a way of dealing with it,you keep it to yourself

A call to a couple of manufacturers,on repairing their product,will give you an idea of the variation,of the task that dare not speak it's name...

So,NO recommendations,as to a method,due to variety of elements,faults,and liabilities...but...

A HV spark generator,say,off an old diesel hot-washer,can instigate an arc which a small,AM radio antennae can find...i hear.

Prolonged HV arcing,may clear any link,across the fault,which could allow one side only,to carry line voltage,which may be detected,with an adjustable volt-finder...maybe...

The bottom line,as always,is time,and money. In the opposite order.

It can be cheaper,to just plumb in a new radiator

 

[marconi]

Soulsurfer - this idea is tentative and you would need to co-opt some electronics and computer hobbyists to work up a prototype and do some experiments. Do you have such a club nearby? They may do it for the challenge it presents rather than payment and all you would have to fork out for are some simple components.

Broadly speaking the idea is to listen for an arc at the break in the heating cable - the arc being created and repeated at a rapid rate by a spark generator.

So the first step is to make a spark generator and cobble together a transducer and amplifier and oscilloscope. The transducer needs to be lightly glued to the floor above the heating cable. Is it possible to hear/see the signal on the scope caused by the arc?

Next, take 4 such transducers and make an amplitude monopulse receiver - this enables up/down and left/right with respect to the centre to be indicated by difference and sum signals. see:

monopulse antenna - Google pretraga - https://www.google.co.uk/search?q=monopulse+antenna&tbm=isch&source=iu&pf=m&ictx=1&fir=fkCNCzFqXTSeFM%253A%252CdDJ00sUfmC5c0M%252C_&usg=__kqlIkdJxNgAFndizbKeCK3orhfM%3D&sa=X&ved=0ahUKEwjInPj4r77XAhUIfRoKHch2DK0Q9QEISzAH#imgrc=fkCNCzFqXTSeFM:

What you now need is some sort of visual display like a C scope in radar:

to display the two difference signals - this is were the computer guys/gals do some work.

If this came together and worked you could locate the sound of the arc - it would of course be when the 4 transducer array has been placed centrally over the point of arcing because then the two difference signals are smallest/zero and the sum signal is largest.

These are the transducers I thought you might try or something similar:

stick on transducers | Rapid Online - https://www.rapidonline.com/catalogue/search?Query=stick%20on%20transducers&Tier=Ultrasonic%20Sensors

This paper helps you understand the frequency range of an spark:

https://www.acoustics-engineering.com/files/SPARK TRAIN MEASUREMENTS.pdf

 

[telectrix]

or shove 11kV down it and see where the floor bulges.

 

[marconi]

or shove 11kV down it and see where the floor bulges.

 

[marconi]

Telectrix prompted me to think again about a simpler scheme.

What about doing what Telectrix said, make a 'decent' spark generator to produce a repeating audibly loud spark and then use a doctor's stethoscope to listen through the floor for the arc/spark? Painstaking, prone work might pay off in localising to an area if not a point. Cheaper, quicker and easier to try out than what I cobbled together in my mind earlier.

Sparker from: car battery, ignition coil, interrupter, HV leads and croc' clips?

or

Gas hob igniter?

We will cause this the TeleMarc method and patent it to become millionaires.

 

[Soulsurfer]

So basically a coil some kind of switch that can handle hv generated like a set of points and croc clip onto the mat tails ?