The N2-GEN™ CPi & CPx Series uses a 7-segment PLC display mounted on the control panel. This article covers normal run modes, how to use the controller, alarm behavior, and how to stop the system.
Controller Overview
The controller display shows three types of information: current run mode (left display), run hours (right display), and alarm status. The controller operates in a locked state by default to prevent accidental changes during normal operation.
To unlock the controller, press and hold the Mode Select button until the display changes from LOCK. Repeat to re-lock. The controller must be unlocked to access the alarm simulation and filter reset functions.
Run Modes
| Display | Color | Meaning |
|---|---|---|
| Run | Green | System is producing nitrogen and filling the storage tank |
| StdbY | Yellow | Storage tank is full (65–75 PSIG); nitrogen production paused |
The system transitions between Run and Standby automatically. When the tank reaches 65–75 PSIG, the generator enters Standby and the compressor shuts off. When the tank pressure drops 7–10 PSIG below the cut-out point, the system automatically restarts.
The PLC controller determines which mode to enter on startup and displays the current mode immediately.
Starting & Stopping
The power switch is located on the upper left side of the control panel. With power on and all gas connections made, the system starts automatically and begins filling the nitrogen storage tank.
For a normal shutdown, close the nitrogen outlet valve on the storage tank, then turn the power switch to Off. In an emergency, the power switch can be turned off immediately to stop all generator functions.
Controller Functions (Unlocked Mode)
With the controller unlocked, two additional functions are accessible:
Alarm Simulation — Hold the Alarm Simulation button for 3 seconds to trigger a simulated alarm condition. This trips the alarm dry contact output (if installed) for 2 seconds, allowing BMS wiring to be confirmed. The system returns to normal operation after the test.
Filter Change Reset — After replacing the filter elements, hold the Filter Change Reset button for 7 seconds. An audible beep confirms that the 1,000-hour filter timer has been reset and the filter alarm cleared. See the Filter Maintenance article for the full replacement procedure.
Alarms
Filter Alarm — Triggered when the generator has accumulated 1,000 run hours or 1 year since the last filter reset, whichever comes first. The system continues to run. Replace filters and reset the timer as soon as possible. See the Filter Maintenance article.
BlastOff® Alarm (optional) — Activated when the system detects characteristics of a gas leak — specifically, the generator running continuously for an extended period without reaching standby pressure. The display shows bōFF and the audible buzzer activates. If a dry contact is wired, the BMS will receive the alarm signal.
To reset a BlastOff® alarm: inspect all fittings, connections, tubing, and downstream plumbing for leaks using soapy water. Once the leak is confirmed repaired, turn the power switch off then back on to reset the alarm and return the system to normal operation.
Troubleshooting Quick Reference
| Symptom | Likely Cause | Action |
|---|---|---|
| No power / no display | Power cord, breaker, or GFCI | Check power cord connection; locate and reset building breaker or GFCI. If breaker continues to trip, the circuit may be overloaded. |
| Low tank pressure / system never reaches Standby | Leak in system, damaged component, or low supply pressure (CPx) | Check power; check supply pressure (CPx); perform leak check throughout system. Contact South-Tek if unresolved. |
| bōFF on display / audible alarm | BlastOff® leak detection triggered | Locate and repair leak; power cycle once to reset alarm after repair. |
| Filter alarm active | 1,000 hrs or 1 year reached | Replace filters per the Filter Maintenance article; reset timer with Filter Change Reset button. |
Contact South-Tek Systems
Phone: (910) 415-1880
Email / Ticket: support@southteksystems911.zendesk.com