[Latitude 28]

Richard,
Ohmed out the loops with the following results;

• Front checked out @ 34.5 ohms
  
• Back checked out @ 18.5 +-
  

Without knowing what the spec is supposed be I downloaded the attached mat specification sheet which gave the readings for the different sized mats.  Without knowing the size of the mat you pretty much have no idea what it is supposed to be.

While disconnecting the controller I came across an ohm reading notation written on the inside of the double gang electrical box (pics attached).

• Front supposed to be 35.5 ohms...the tolerance is +- 10% so that at least checks ok
  
• Back supposed to be 66.5 so a reading of 18.5 ohms is out of tolerance.
  

Then off to checking for a short to grounds

• Front had a high resistance "fluctuating" ohm reading
  
• The back pretty much a solid short to ground.
  

Doing some research the newer NuHeat T-stats have a built in GFIC.   Could not verify if the Paktronic unit we use has a built in GFIC circuit or not....but most likely it does.  That being the case, older GFIC are prone to failure and could explain the possibility of both Paktronic units being bad given the same age. Just for grins, I swapped the back Paktroic to the front to see if I could get at least the front working with no help.  From a previous house wiring problem I had I know GFIC will trip with a High resistance ground under load.  but will seem to work fine with small loads.

Calling all the dogs back on the porch with this....looks like I have a shorted mat in the back and possibly a mat problem in the front.  Along with suspect Paktronic units/GFIC.  Looks like we will be enjoying cold floors till we remodel:-)

Steve