nJoin Power Module (USG-4000)

The nJoin is an intuitive Power Module with built-in GFCI for large electric floor heating applications. The nSpire Touch, nSpire Touch Wifi, nHance and nTrust thermostats can be extended with additional nJoin power modules. Output can be increased by 15 A per nJoin module.
This support page provides publications, manuals, videos, support articles, and common support questions for the nJoin Power Module product line.

Main Products (2)

Common Support Questions (14)

Publications and Manuals (5)

Videos (1)

Articles (2)

Create a new Support Request

Main Products

Do you need support or specifications for a specific model? Identify your model below.

USG-4000

nJoin Power Module with Class A GFCI Past Model

ASG-4999

nJoin Power Module, 15mA EGFPD Past Model

Common Support Questions

What breaker and wire size do I need to use for a floor heating system?

The breaker and wire sizes are selected based on the total amperage of the WarmlyYours heating system connected to a single thermostat. This information is on the WarmlyYours heating system's installation plan, electrical plan, or UL label. Based on guidelines from the National Electrical Code: loads up to 16 Amps may utilize 12 gauge wire with a 20-Amp breaker, and loads up to 12 Amps - 14 gauge wire with a 15-Amp breaker. Local code and/or other factors may change these guidelines.

6 people found this helpful. Did you find this helpful? Yes No

Can a thermostat be placed on an exterior wall?

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.

3 people found this helpful. Did you find this helpful? Yes No

How do I turn off the OJ Microline?

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.)

1 person found this helpful. Did you find this helpful? Yes No

What does the Ground Fault Circuit Interrupter (GFCI/GFEP) do that the Circuit Breaker doesn't?

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.

1 person found this helpful. Did you find this helpful? Yes No

Why do relays fail?

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.

1 person found this helpful. Did you find this helpful? Yes No

Will a circuit breaker protect against a power surge?

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.

1 person found this helpful. Did you find this helpful? Yes No

How is the slab heating system controlled?

You can control your slab heating system with any WarmlyYours nSpiration Series thermostat. Depending on the size of your project, you may also need to add a relay or nJoin power module.

Did you find this helpful? Yes No

At what height is the thermostat mounted?

All thermostats are mandated at 42" height for handicap accessibility, most private residences are mounted at 52-60".

Please see this video on how to install a WarmlyYours nSpiration Series thermostat.

Did you find this helpful? Yes No

Does the adaptive function reset when making a factory reset?

Did you find this helpful? Yes No

How do you make the USG (nJoin USG-4000 power module) shut off when the thermostat switches off?

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.

Did you find this helpful? Yes No

Is the OJ Microline nJoin power module a direct replacement for the CT230?

No. The nJoin power module is not compatible with a Honeywell system.

Did you find this helpful? Yes No

The GFI Red Light is permanently ON

This indicates a fault, current to ground. The thermostat has cut off the power for your safety. Please contact your local electrician or WarmlyYours Technical Support.

Did you find this helpful? Yes No

Where to connect the ground wire of floor mats/cables?

The ground wire in the floor mat must be connected directly to the ground wire of the supply or to the house ground wire.

Did you find this helpful? Yes No

Why does a GFCI (Ground Fault Circuit Interrupter) fail?

GFCI can fail for various reasons, such as wear and tear, moisture, corrosion, power surges, faulty wiring, or improper installation. Some of these causes can be prevented by regular inspection and maintenance, while others may require professional assistance. It is important to note that GFCI devices (ex. thermostat, breakers, outlets) should be tested regularly as these do wear out over time.

Did you find this helpful? Yes No