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N2-GEN TS, CS, and S Series — Alarms & Troubleshooting

Updated
Applies to: N2-GEN TS, CS, and S Series PSA nitrogen generators

This article explains how to set up and read the generator's alarms, including the optional BlastOff and PurityProtect features, and provides a troubleshooting guide for common operating problems.

Alarm setpoints

The Alarms / Filter Parameters menu shows the O2, high dew point, and low-pressure alarm setpoints, each next to its current value.

TSCSS_Alarms_Fig1_setup.png


Figure 1: Alarm Setup screen

  • The O2 High Level alarm (shown as O2% or O2 PPM Max, depending on your analyzer) triggers when the current oxygen reading rises above the setpoint, meaning purity has fallen below target.
  • The Low N2 Tank Press alarm triggers when the current nitrogen tank pressure falls below the setpoint.
  • The High Dew Point setpoint is shown here as well, in °F.

The box next to each item is the user setpoint. Alarms can be disabled with the Alarms Enabled? toggle on the Other Settings screen, where the local audible can also be turned on or off.

Other alarm options (BlastOff, PurityProtect)

Not all models have every option below. These are found on the Other Settings screen.

  • Alarms Enabled? The master toggle for all system alarms. Set it to Yes when setting up any alarm. The audible buzzer for all alarms can also be toggled here.
  • BlastOff (if included). Triggers an alarm if the unit has been running non-stop for the BlastOff timer setting, which can indicate a leak in the system or that the unit is being overdrawn.
  • PurityProtect (if included). Activate it by setting PurityProtect Active? to Yes and entering a delay time (HH:MM, for example 00:05 = 5 minutes). The delay time is how long the system must be in spec before switching from Purge Mode to Process Flow Mode. The warmup time pre-purges the system on a manual restart. PurityProtect only purges if the option is included with the package.

Alarm status, details, and history

The red Alarm button in the bottom right corner of the home screen opens the Alarm Status screen, which shows current alarm statuses. From there you can open Filters Info, Alarm Details, Alarm History, or Clear History.

TSCSS_Alarms_Fig2_status.png


Figure 2: Alarm Status screen

  • Alarm Details lists the alarms and when each was triggered (time and date).
  • Alarm History logs each alarm, when it triggered, its time, duration, and when it deactivated. Up to 256 alarms are stored.
  • Clear History clears the alarm history log; a confirmation screen asks you to enter 1111 to confirm.

Filter status alarms

The Filter Info screen shows each filter element's status as Good or Overdue, and the Alarm Status screen flags filters as Overdue when due. When a filter shows Overdue, change the corresponding element as soon as possible, then reset its filter calendar by pressing the corresponding green reset button.

ℹ Note Replacement intervals depend on your unit's generation, and the change procedure is covered separately. See the Filter Maintenance article and the Preventive Maintenance schedule.

Troubleshooting

Use the guides below to find the likely cause of an operating problem and its remedy. When several causes are possible, investigate the simpler ones first. Some checks involve electrical or mechanical work that should be performed by a qualified technician, and some require contacting South-Tek. If you need further assistance, contact South-Tek Systems.

ℹ Note Steps marked “Technician” involve electrical or mechanical diagnostics that should be carried out by qualified personnel. When in doubt, stop and contact South-Tek.

Jump to a symptom:

Low N2 purity / high O2 reading

The unit cycles normally but the oxygen reading is above setpoint or the purity alarm is active.

Possible cause Recommended action
Product flow higher than the unit can support at the target purity Reduce the nitrogen draw. Compare actual consumption to the unit's rated flow at your required purity.
Inlet air too wet or too oily Confirm the inlet dew point meets the unit's specification (38°F / 3°C or better; some units require much lower). Inspect the pre-dryer and coalescing filters. See Site & Utility Requirements.
Feed air pressure below design Confirm feed pressure is at the unit's design point (within the 100–150 PSIG range). Low feed pressure lowers purity and product pressure.
Downstream leak diluting the product Perform a full leak test on product piping, valves, and connections.
O2 sample flow port valved off Open the O2 sample port so the analyzer sees product gas.
Analyzer purge/exhaust port blocked Confirm the analyzer purge line is clear and unrestricted.
Reading is wrong rather than purity being low See “High O2 alarm — possibly false or drifted” below.
Beds have not recovered after a restart or PM Allow the system to cycle and stabilize before judging purity; freshly serviced or topped-off beds need cycles to equilibrate.
Suspected oil-contaminated CMS Notify South-Tek; bed replacement may be required.

High O2 alarm — possibly false or drifted reading

The O2 alarm is active but readings look stable or inconsistent with performance, or the alarm appears at a cold start and clears after warm-up.

Possible cause Recommended action
Analyzer not warmed up Allow 15–20 minutes of warm-up after a cold start before trusting analyzer readings.
Calibration drift Verify the analyzer against certified test gas and recalibrate using the current procedure. See Oxygen Analyzer & Sensor Calibration. Note: on PPM units the current method uses factory set points and treats calibration gas as verification only.
Sensor cell at end of life Replace the O2 sensor cell if calibration will not hold. Typical fuel-cell life is 1–2 years.
Sample line leak drawing in ambient air Check sample-line fittings and tubing for cracks or loose connections.
Alarm setpoint misconfigured Confirm the O2 alarm setpoint matches the customer's required purity spec.

Gradual purity decline over weeks or months (CMS degradation)

Purity slowly declines, the unit cannot reach rated purity at any cycle setting, and carbon dust may appear in a downstream filter housing.

Possible cause Recommended action
Oil contamination from the compressor (the most common cause of CMS failure) Inspect the upstream coalescing filter elements for oil saturation. Confirm compressor oil carryover is very low, on the order of 0.01 ppm or less at the generator inlet.
Moisture ingress or liquid carryover over time Confirm no liquid carryover events have occurred; water slugs destroy CMS rapidly. Verify pre-treatment dryer performance.
Physical bed damage or end of service life CMS typically lasts 10+ years under clean, dry conditions. Early decline means the root cause should be investigated first.
Carbon dust in downstream piping or filter housing Bed containment may have failed. Contact South-Tek.

Moisture in the N2 product stream

Wet product line or condensation, moisture reaching downstream equipment, or water at drain points past the generator.

Possible cause Recommended action
Pre-treatment dryer not functioning Verify the dryer is operating and check its outlet dew point against the unit's requirement (38°F / 3°C or better).
Heatless desiccant dryer: purge or desiccant problem Confirm purge-valve function and desiccant condition.
Refrigerated dryer: refrigerant, drain, or condenser fault Check refrigerant pressure, drain function, and condenser cleanliness.
Filter drain traps flooded or not cycling Confirm drain traps on all filters are cycling and not flooded.
Pre-treatment stage bypassed or missing Confirm the pre-treatment stage is installed and in service.
⚠ Warning CMS is highly moisture-sensitive. Sustained wet air will permanently degrade the beds.

Insufficient N2 flow / low delivery pressure

Product pressure is below setpoint, downstream processes are starved, and the unit may run continuously without satisfying demand.

Possible cause Recommended action
Demand exceeds the generator's rated capacity Compare actual N2 consumption to the rated capacity at the required purity. If demand has grown, contact South-Tek about upgrade options.
Compressor outlet pressure too low Verify compressor outlet pressure; low feed pressure produces low product pressure.
Clogged inlet particulate or coalescing filter Inspect and replace inlet filter elements. See Filter Maintenance.
Partially closed isolation valve Confirm all manual isolation valves are fully open.

Not building any storage pressure

Tank pressure does not rise at all.

Possible cause Recommended action
Faulty process valve Have a technician confirm each valve is operating; see “Switching/process valve not actuating” below.
Defective wiring Have a qualified technician check all wiring connections.
Disconnected pneumatic line or leak Check all pneumatic lines for leakage.
No air pressure to the pilot valves Confirm the pilot valves are receiving adequate pressure (pilot/instrument air is typically around 60–80 PSI; confirm against your unit's spec).

Generator running continuously

The unit never reaches standby / cut-out.

Possible cause Recommended action
Incorrect cut-out pressure Restore the cut-out pressure to the factory setting. See Purity, Pressure & Standby; contact South-Tek before changing setpoints.
Defective wiring from the pressure transducer to the touchscreen Have a technician check the wiring connections.
Excessive N2 leakage Correct all N2 leakage.
Cycle pressure too low Check the incoming air source and the internal air pressure regulator.
Demand exceeds capacity See “Insufficient N2 flow / low delivery pressure” above.

Not cycling or abnormal cycle times

The unit is not cycling at all, the towers cycle too fast or too slow, a cycle-timer fault is shown, or one tower is stuck in a phase.

Possible cause Recommended action
System is OFF (left button on the home screen is red) Touch and hold the red Start/Stop button for about 2 seconds until it turns green.
Low voltage or amperage Check the electrical source.
Circuit breaker tripped Reset the breaker after identifying the cause.
Fuse blown Replace the fuses on the electrical panel.
Low operator/pilot air pressure Check the incoming air source and the internal air pressure regulator.
Cycle timer settings incorrect for actual demand Confirm cycle parameters match the commissioning baseline. Re-optimization may be needed if demand has changed; contact South-Tek.
Pressure sensor drift sending false input to the PLC Compare tower and tank pressure readings to a calibrated gauge; replace the sensor if drifted.
Valve fault preventing tower switchover See “Switching/process valve not actuating” below.
PLC program or I/O fault Have a technician monitor the PLC I/O during cycling to confirm valve outputs toggle; contact South-Tek.

Switching / process valve not actuating

A valve-fault alarm is active, one tower is stuck in a phase, there is hissing or exhaust noise during pressurization, or purity fluctuates.

Possible cause Recommended action
Solenoid coil failure Technician: check the solenoid LED indicator (no light indicates an electrical fault) and verify 24 VDC at the coil. Swap with a known-good coil to isolate electrical vs. mechanical fault.
Valve body wear or debris ingestion Technician: if safe, manually actuate the valve to confirm mechanical function, and inspect the exhaust ports for debris or moisture causing sticking.
Loss of pilot air to the actuator Confirm the pilot/instrument air supply is adequate (typically around 60–80 PSI).
PLC output failure Have a technician verify the PLC output; contact South-Tek.
ℹ Note A brief hiss during bed equalization or repressurization is normal. Continuous hissing or exhaust noise during pressurization is not and points to a valve problem.

Generator will not start / blank touchscreen / no power

No display on the touchscreen, the unit is unresponsive, an E-stop light is illuminated, or the main breaker has tripped.

Possible cause Recommended action
E-stop engaged (local or remote) Confirm all E-stop buttons are pulled out and reset, including local and remote E-stops.
Main breaker or fuse tripped Inspect the main disconnect, breakers, and fuses. Reset only after identifying the root cause.
Incoming power phase loss or out of range Technician: check incoming voltage at the main panel; all phases must be within ±10% of nameplate.
Control power supply failure Technician: inspect the 24 VDC control power supply LED output indicator.
PLC power module failure Technician: if the PLC power LED is off while control power is present, the PLC power module may have failed. Contact South-Tek.

Excessive pressure drop across the beds

Feed pressure is significantly higher than product pressure, the unit takes longer to reach setpoint, or cycle times are increased or erratic.

Possible cause Recommended action
Inlet filter differential pressure too high Check the inlet filter differential pressure and replace elements if it exceeds the limit. See Filter Maintenance.
Clogged tower inlet screens or diffusers Inspect inlet/outlet screens for carbon dust or debris accumulation.
Excessive feed air velocity fluidizing the bed Review feed air flow against the unit nameplate; oversupply can fluidize the CMS bed.
CMS dust in downstream piping Bed containment may have failed. Contact South-Tek.

High pressure fault / safety relief valve lifting

A high-pressure alarm is shown, the safety relief valve is venting, or product pressure is above setpoint.

Possible cause Recommended action
Downstream isolation valve closed with the unit running (dead-heading) Immediately verify all downstream isolation valves are open. Dead-heading causes rapid overpressure.
Pressure regulator failed or miscalibrated Check the regulator setting against the process setpoint and adjust if drifted.
Relief valve setpoint too low or not reseating Inspect the safety relief valve after it lifts; verify it fully re-seats and does not weep.
Product pressure transducer reading incorrectly Calibrate or replace the transducer if the touchscreen reading differs from the local gauge.
⚠ Warning Never bypass the safety relief valve or raise its setpoint beyond the design pressure. If you believe the valve is sized incorrectly, contact South-Tek.
▲ Before you escalate When contacting South-Tek, please have ready: the unit serial number, inlet conditions (pressure and dew point), the current purity reading, and the touchscreen fault/alarm log.
Need help? South-Tek Systems Service — Phone: (910) 415-1880 · Open a support ticket at support@southteksystems911.zendesk.com or through the Help Center.

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