Use this article to diagnose common issues. Most problems trace back to a leak or the air supply. Work through the section that matches your symptom, and contact South-Tek Systems if the issue is not resolved.
No power
If the unit has no power, the loss of nitrogen production becomes apparent once the storage pressure drops.
- Check the power cord and its connection.
- Check whether the building circuit breaker or GFCI has tripped. Locate the breaker and reset it. If it keeps tripping, the circuit may be overloaded, so have an electrician check it.
- On hard-wired units (TL-1725), check the 7 A time-delay fuse on the internal panel.
Low or dropping storage pressure
The system builds nitrogen to about 70 (±3) PSIG and then enters Standby, returning to Run when the pressure drops 7 to 10 PSIG. The gauge on top of the cabinet should read roughly 50 to 80 PSIG.
- If the pressure is low, check the power first.
- Check for leaks throughout the system (see Checking for leaks).
- On external-air units (TL-1825, TL-1725), confirm the incoming air supply is at its design pressure and the air valve to the generator is open. Low feed-air pressure prevents the beds from fully pressurizing and drops both pressure and purity.
- Check the filter auto-drains. A drain stuck open bleeds air continuously and mimics a leak; a drain stuck closed lets liquid collect in the bowl.
- On integral-compressor units (TL-450, TL-1050, and Plus), long fill times or never reaching cut-out with no leak found can indicate a worn compressor or a clogged intake filter. On hot days these units can also nuisance-trip on thermal overload, so confirm ventilation and ambient temperature are within spec.
- If the system operates outside these specifications, contact a factory-trained technician.
Overdraw and downstream leaks
A slowly growing leak in the transmission line or downstream piping is one of the most common causes of trouble on these systems, and it often shows up as the generator being blamed. As demand rises, the unit runs harder to keep up, so the first signs are usually a steadily increasing duty cycle (running more, standing by less), a slow decline in delivered purity, or a generator that never seems to reach cut-out.
- Compare the actual nitrogen demand against the unit's rated output. If the line is asking for more than the generator is rated to deliver at specification, the system is being overdrawn and purity or pressure will fall even though the generator is healthy.
- Treat a steadily rising duty cycle as a downstream leak until proven otherwise. Use the standby decay test in Checking for leaks to confirm whether the loss is downstream of the generator.
- Compare current fill time, cycle time, and duty cycle against the baseline recorded at commissioning. A clear drift from baseline is the fastest way to catch a growing leak early.
Checking for leaks
- Listen for leaks and spray soapy water around the connection ports (non-electrical parts only).
- If a leak is found, isolate the area and relieve pressure before working on it. Fix the part and return the system to operation.
- If no leak is found, turn off the unit and isolate sections to find where the pressure loss occurs.
- To locate a downstream leak, put the unit in Standby and wait 5 minutes. If it stays in Standby, the leak is downstream of the generator. Read the storage tank pressure: if it changed, the leak is in the tank fittings; if it did not, check the building pipe lines.
Gas leaks at fittings
Use a spray bottle only on non-electrical equipment to find leaks, then fix or replace leaking fittings or old hoses. Push-to-connect fittings will show bubbles and typically have an acceptable leakage rate of up to 5 ccm.
BlastOff leak-detection alarm (PLC units)
On TL-450 and TL-1050 units, a BlastOff event sounds the buzzer and shows b ōFF in red on the controller. It indicates a probable leak in a line, a regulator, or an unseated fitting.
- Turn off the unit's power switch and check for leaks. If none are found, leave the unit off and contact your technician.
- After the leak is fixed, turn the unit back on. Cycling the power off and on resets BlastOff automatically.
- Do not reset the alarm repeatedly. If BlastOff trips regularly, there is a real leak to resolve.
Alarms on HMI units (Plus, TL-1825, TL-1725)
On touchscreen units, the Alarms screen shows active alarms, and Alarm Details lists each one with the time and date it triggered.
- O2 alarm: the oxygen reading is above the %O2 High Level (or O2 PPM Max) setpoint, meaning purity is out of specification. Check the air supply, check for leaks, and confirm the unit has run long enough for the beds to rebalance after any shutdown or exposure to atmosphere.
- Low N2 Tank Press alarm: the tank pressure is below its setpoint. Check power, the air supply, and for leaks.
- If your unit has the 7100 oxygen analyzer, it can hold an alarm or fault status for up to 30 minutes after a change, even once purity is back in range. Ignore the fault for that window.
Purity loss: what to check
How the purity fell tells you where to look. On HMI units, the trending graph is the fastest way to see whether the drop was gradual or sudden.
- After a first start-up or a prolonged shutdown, the first few cycles may be below design purity until the beds rebalance. Allow purity to rise before drawing product.
- If tank pressure was lost because the outlet was not valved off during a stop, purity may dip briefly at restart.
- A sudden drop points to a switching-valve or cycle-timing fault, or loss of feed air. Confirm the beds are still swinging every 50 to 90 seconds and that the air supply is present and at design pressure.
- A gradual climb over days or weeks points to media contamination from oil or moisture breakthrough, a saturated coalescing element, or an aging bed. Check the filters and drains first.
- If the unit has an oxygen analyzer, rule out the sensor before chasing the system. Galvanic O2 cells drift as they age and can read high near end of life, and blocked or excessive sample flow damages them. Verify the reading against a second source.
- For persistent low purity, verify the incoming air supply meets its design pressure and dew point (external-air units), check for leaks and overdraw, confirm the beds swing every 50 to 90 seconds, and confirm the filters are not overdue. Contact a factory-trained technician if it persists.
Common overlooked causes
- Exhaust muffler or silencer restriction (TL-1825 and TL-1725): a clogged bed-exhaust muffler raises blowdown backpressure and keeps the offline bed from fully regenerating, which quietly kills purity. The tell is a normal-looking fill but sagging purity, sometimes with louder or prolonged exhaust. The smaller integral-compressor units rarely see this.
- Auto-drain failures: a drain stuck closed lets water and oil collect and carry over into the adsorbent media, causing permanent damage; a drain stuck open bleeds air and mimics a leak. The bowls should not be full, and each drain should pulse rather than run continuously or sit dry with standing liquid.
- Bed-switching faults: uneven bed pressures (the 3 to 5 PSIG balance check), a bed that never vents, or continuous rather than intermittent exhaust point to a stuck switching or solenoid valve or a failed pilot. Listen for continuous exhaust between switchovers.
- Compressor capacity loss and thermal trips (integral-compressor units): worn compressor components or a clogged intake filter lengthen fill times, and high ambient temperatures can nuisance-trip the compressor on thermal overload.
- Cold-weather condensate freezing: below freezing, auto-drains and condensate lines can freeze and block drainage, causing carryover or pressure faults. This is worth checking on outdoor and cold-location installs.
Low-pressure alarm contact
The field-wired low-pressure switch is preset at 1 PSIG and resets when pressure rises 1 PSIG above the setpoint. If it trips, the system is below its set pressure. Check power, the air supply, and for leaks.
When to contact South-Tek Systems
If a problem cannot be resolved with this article, or the system operates outside its specifications, contact South-Tek Systems. Only factory-trained, authorized personnel should perform warranty work; unauthorized work or non-factory parts may void the warranty. Request an RMA number from the factory before returning any part.
Related articles
- TL Series — Filter Replacement & Preventive Maintenance
- TL Series — Startup & Commissioning
- TL Series — System Operation (Legacy: TL-450 & TL-1050)
- TL Series — HMI Controls & Operation
- TL Series — Safety Guidelines