Floor heat thermostat

[nizak]

I installed a 2 pole thermostat for Schluter in floor heat.

When I went to energize the circuit the breaker tripped immediately. I removed the stat, checked the nm cable and found there was still a fault somewhere.

I traced the cable and found where the HVAC contractor ran a screw through the cable while supporting a gas line.

After repairing the line, I installed the stat and energized the circuit. Set the stat in manual mode and found the amp draw was right where it should be according to the mat specs.

In an attempt to test the integral GFCI I found it would not work. I also found that the temperature would no shut off when it reached the setting.

Could the fault that occurred damage the stat in some way?

I have never had a bad stat out of the box. Have used several different brands over the years and never had this type of problem.

Thanks.

 

[GoldDigger]

If the fault was on the downstream side of the thermostat the fault current may well have welded the contacts together if it is a mechanical stat. Or destroyed the switching element if it uses a solid state relay.
How did you test the integral GFCI? It is certainly possible that the fault current messed up the electronics too.

 

[nizak]

The fault was found approx. 15 lineal feet before the stat.

I tested the ground fault by pushing the "test" button on the stat.

That is the way the specs show how to test it.

 

[GoldDigger]

The fault was found approx. 15 lineal feet before the stat.

I tested the ground fault by pushing the "test" button on the stat.

That is the way the specs show how to test it.

With the fault occurring before the stat, I find it hard to figure out how the stat could have gotten damaged.