nJoin Power Module with Class A GFCI (USG-4000)

In theory, it is possible, if no other options are available. We do not recommend it, but If the thermostat is controlling the floor temperature with a floor sensor, then it can go on an exterior wall. It is important that the floor sensor gets located in an area of the floor not hit by sunshine.

If the thermostat will be controlling the air temperature with the built-in ambient sensor, then it should go on an interior wall.

A GFCI/GFEP (Ground Fault Circuit Interrupter / Ground Fault Equipment Protection) works differently than a circuit breaker by specifically detecting a small imbalance in electrical current between the hot and neutral wires, which indicates a potential ground fault (like a person touching a live wire), and instantly shutting off the power to prevent shock, while a circuit breaker only trips when there's a significant overload in current flow on the circuit, like a short circuit or too many appliances plugged in.

Pressing and holding (2-3 sec) physical power/reset button will turn the unit completely OFF. Same process turns the unit back on.

(nHance and nJoin units will have the button on the front faceplate, nSpire Touch WiFi, nSpire Touch and nTrust will have the button on the right side of the faceplate.)

Relays can fail due to excessive current or voltage. When a relay is exposed to too much current, the contacts can burn out. High voltage can also damage the coil. Other reasons include mechanical wear and tear, dust or dirt buildup, and moisture. These factors can cause the relay to malfunction or stop working entirely. Regular maintenance and using the relay within its specified limits can help prevent failures.

Check the connections between the thermostat and power module. If the power module is connected incorrectly to the thermostat, the power module won't switch off.

No, a circuit breaker will NOT protect against a power surge; a circuit breakers primary function is to protect against excessive current flow (overload), while a surge protector is specifically designed to handle voltage spikes, which are what power surges are considered to be.

Yes. The floor never free-runs — the thermostat’s floor sensor governs output, and you set a maximum floor temperature limit in the thermostat itself. Most heated tile bathroom floors are set between 80°F and 85°F. Set that limit during commissioning and record it on the handoff sheet so the homeowner does not raise it past the flooring manufacturer’s rated maximum.

Yes, but the tear-out is the real risk. Scan the floor with thermal imaging before demo to map the existing hydronic tubing, and never fasten or drill into it. Keep the two systems on fully independent controls so they cannot fight each other, and do not place the electric floor sensor directly above a hydronic loop — the false-high reading will short-cycle the electric system. Call PRO technical support at 800-875-5285 to review the assembly before ordering.

No. Electric floor heating cable is listed for installation under floor coverings only, and NEC 424.38(A) does not permit heating cable to be installed in walls. Running it vertically voids both the UL listing and the warranty. For warm towels and a little extra room heat, specify a heated towel rack, which is designed and listed for wall mounting.