Finding a break in hot floor wire under tile

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danickstr

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Does anyone have a trick for locating the exact spot the wire would be broken in a radiant floor wire job?

This job is a heartbreaker: an unlicensed contractor came in and did some bad work and charged way too much. :mad: He is currently being sued, but who knows how that will go.

I told the elderly couple I would try to figure a way to find the broken wire, but did not know if I could prevent the tile from having to come up.

I also told them if there was a chance or a way, Mike Holt's forum was the best shot I know of.
 
Many manufacturers have a special tool you can rent to locate the break(s). Call them.

No matter what you find, the tile's gotta come up.
 
Tile's gotta come up, meaning the wire cannot be repaired? Or that it has to come up in a patch area. Finding the break would be meaningless if you still had to remove all the tile.
 
mdshunk said:
Some brands use a special coaxial cable anyhow, so if you did find the break, it's essentially non-repairable.
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Trust me on this! I have entirely too much experiance with this.... They have a special kit....

It consists of:
  • A small ferrule for the center conductor
  • Small shink tubing
  • A large ferrule that goes around the shink tubing (Barely!)
  • And large shrink tubing
Getting enough to work with, up out of a tile floor you had to bust into - nearly impossible....
RPITA!

Getting someone to make the call and actually bust into the floor after you just spend an hour crawling around trying to find it - bigger PITA!

Anyway, the manufacturer can give you the ohms per foot to locate shorts by toning (a good phone toner or circuit tracing gear) and measuring the path of the cable - with some trianglization pretty accurate... With an open you can do basically the same.... Infact easier - because the whole thing isnt ringing - when the tone stops - you found it.

I would suggest a TDR - but in this case - a resistive cable - I haven't tried it.... :wink: But worth a try.... You would have to get a test sample for the VOP.

Once found - I have done these under a single tile - on a few occasions had to pull up / SMASH a few tiles. But it can be done. I'm usually nice and leave that task to the tile guy - as it is usually his dime that I am standing on.... :rolleyes: Don't want to go too far....

For future installs they have a little box that connects to the leads that beaps when you cut or short the cable - with some inginuity - it can be connected to operate a 10" fire bell! :wink:
 
Denis said:
would infrared viewing or temp gun do the trick?
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I would think the cable would have to be unbroken for the circuit to be complete so it can create heat so the camera or gun can 'see' the heat....
 
Get a neon sign transformer or a transformer from an electronic air cleaner, and a Variac.
Crank up the voltage across each end of the broken conductor just enough for an arc to form across the gap (~1 kV).
Use an AM radio as a signal tracer to listen for the radio noise from the spark.
This method may destroy the conductor insulation, depending on its rated breakdown voltage.

Or, put 120v on one end of the wire w/respect to ground, i.e., hook up a fused (~1 amp) black wire from a wall outlet. Use one of those cheapie non-contact voltage sensors to find where the signal stops; to the extent that tile is nonconductive this method might actually work. . .

If either works, my patent attorney stands at the ready.
 
wptski said:
How far below the surface would the wires be? Tile over concrete with rebar?
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The cable type systems generally have a 1/4" or so of leveling compound over them that is allowed to cure, then thinset and tile. Some tile guys shortcut the leveling step and just put thinset on really thick and set the tile directly so they can get done in one day. The actual finished surface can be from 1/2" to 1" from the actual cable.
 
a trick for locating the exact spot

a trick for locating the exact spot

I'm thinking now that TDR, discussed in other posts, may also work here.

You shouldn't get any false readings from crimps, kinks, etc., just a clear signal from the break and from each end.

Instead of coaxial cable with a center conductor, insulation and a shield, you would have a center conductor surrounded by grounded concrete.

I guess concrete is more of a conductor than an insulator, but the instrument may have a way of compensating for this.
 
I have seen a contractor recommended by NuHeat use a hi-pot tester and a heat sensitive film. The film changed color when over the shorted wire. He slid several of these 1'x1' films around the floor and found the short within 30 minutes, busted out the tile and repaired the cut wire with a special crimp he had.
 
The only thing that come to mind is one of those voltage sensors that glows when it comes close to an energized conductor. I have one that looks like a pencil amde my Fluke.
If I were to attampt to locate the break I would appy 120v it one end of the wire feeding the heat wire. Take themay voltage sensor and start following the wire marking the tile with a water based marked that can the washed way later.
Then I stop getting a voltage indication I would assume that the wire may be broken at the point and mark it.
I would disconnect the 120v applied on that wire and attached it to the other and start tracing again from the other direction. If you come to the same poing where there is no voltage indication that would be an indicator of a boken wire. Hopefully thap pint will be the same point located from the other direction.
 
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