N2-BLAST® FPS-1650, FPS-3250 & FPS-5000 — Safety Guidelines – South-Tek Systems

Applies to: South-Tek Systems N2-BLAST® FPS-1650, FPS-3250, and FPS-5000 fire protection nitrogen generators.

Does NOT apply to: FPS-500 and FPS-900 (see their safety guidelines) or FPS-10000, FPS-16500, and FPS-22500 (see theirs). The hazards overlap but the isolation procedures do not.

This article is the safety reference for installing, operating, and maintaining the FPS-1650, FPS-3250, and FPS-5000. It covers who may work on the equipment, the hazards it actually presents, how to isolate and verify each energy source before mechanical work, and what to do when something goes wrong. Read the O&M manual before performing any work on the system, and for external air compressors and dryers follow those manufacturers' own safety instructions as well.

⚠ Warning — this is a pressurized system on a life-safety application The generator holds compressed air and nitrogen under pressure, is connected to an energized electrical panel, and supervises a fire sprinkler system. Only trained, competent, authorized personnel may install, operate, maintain, or repair it. Isolate and depressurize before any mechanical work — including a filter change. Use only approved replacement parts that meet or exceed the original specification. Do not tamper with the equipment, and do not operate it outside its published specifications.

Who may do what

Most of the incidents on this equipment come down to the wrong person doing the right task. The owner is responsible for keeping the unit in safe working condition; the split below is the practical version of that.

Task	Who	Why it matters
Reading the screen, noting an alarm, reporting it	Anyone briefed on the system	No hazard, and the sooner an alarm is reported the smaller the problem.
Starting and stopping the unit at the touchscreen	Trained operator	Stopping the unit takes the riser off active nitrogen replenishment. That is an operational decision, not a neutral one.
Filter changes and preventive maintenance	Qualified service technician	Requires isolating and depressurizing a live pressure system, and correct sequencing to avoid venting the riser.
Electrical connection, panel work, three-phase rotation checks	Qualified electrician	Live panel work. Supply voltage is factory configured and must match the incoming service.
Changing setpoints, control programming, internal repairs	South-Tek, or with South-Tek's written consent	The control program is proprietary and password-protected. Unauthorized changes void the performance specification and the warranty.
Anything on the external compressor or dryer	Per that manufacturer's instructions	Separate equipment with its own hazards, its own lockout points, and its own manual.

The hazards on this equipment

Hazard	Where it comes from	How it is controlled
Oxygen displacement asphyxiation	Nitrogen vented from the generator, the purity sample port, a relief valve lifting, or an open line. Nitrogen is not poisonous, but it pushes oxygen out of a space — and it is colorless, odorless, and gives no warning. You do not smell it, and the first symptom can be collapse.	Install in a well-ventilated room that is not sealed off from normal air changes. Vent exhaust gas outside or into a large ventilated space. Never enter a confined space downstream of a vent without confirming at least 19.5% O₂ with a calibrated oxygen meter.
Stored pressure	Feed air up to 125 PSIG on the FPS-3250 and FPS-5000, nitrogen in a 200 PSI-rated storage tank whose relief valve is set at 135 PSI, and pressure trapped in filter bodies, the feed receiver, and interconnecting piping after the unit stops. Do not calibrate your caution to the feed-air number.	Isolate, vent, and verify zero on every section before opening it. See the isolation section below.
Whipping hose	A pressurized hose that is not secured, or one that bursts in service.	Secure both ends before pressurizing, and confirm the restraint before opening any valve. Never let pressurized gas exhaust from an unsecured hose. If one bursts, close the isolation valves if it is safe to do so and shut the unit down — do not try to grab the hose.
Electrical	The control panel and, on the FPS-3250 and FPS-5000, the external compressor's motor circuit — often three-phase.	Disconnect supply power before any electrical work. The panel is an open-type industrial control panel, so the cabinet is its enclosure — do not run the unit with the panel exposed.
Automatic start	The generator starts and stops on its own, on tank pressure. A unit sitting quietly in Standby is not a unit that is off.	Stopping at the touchscreen is a control action, not an energy isolation. Open the disconnect before working inside the cabinet.
Noise	Under 90 dBA at the cabinet, plus the external compressor on the FPS-3250 and FPS-5000.	Wear hearing protection while the equipment is running.
Weight and handling	A tall, narrow cabinet at roughly 223–303 lb depending on model, delivered in a crate.	Keep it upright, move it with a floor jack, and never stack anything on top of it.
Loss of supervision the life-safety hazard	Valving the generator off, leaving a valve shut after a test, or leaving a system on air instead of nitrogen.	Treat it as an impairment — see the impairment section below. This is the hazard that hurts a building rather than a technician.

Personal protective equipment

PPE	When
Safety glasses	Any time the cabinet door is open with the machine running, and any time you are opening a pressurized component or leak-checking.
Hearing protection	While the equipment is running — the generator and, on the FPS-3250 and FPS-5000, the feed compressor.
Calibrated oxygen meter	Before entering any confined or poorly ventilated space downstream of a vent, or any space where nitrogen may have accumulated. Confirm at least 19.5% O₂ before entry.
Gloves	Handling the cabinet, crate, or sheet metal edges, and when working around a compressor that has been running.
Electrical PPE per site policy	Any work at the panel, at the disconnect, or on the compressor motor circuit.

Isolation and lockout — before any mechanical work

This equipment has five separate energy sources, and stopping the unit at the touchscreen isolates none of them. Isolate each one and then verify it, in pairs — an isolation you have not verified is an assumption.

Order matters. Work through it like this:

Stop the unit at the touchscreen and let it complete. On the FPS-1650 this is also what relieves the air side.
Close the isolation valves — nitrogen outlet, tank valves, main air input (FPS-3250 / FPS-5000), and the bypass air inlet where auto air bypass is fitted.
Open the disconnect and lock it out, at the generator and at the external compressor and dryer.
Vent each section you intend to open, at its named vent point.
Verify each one — gauge at zero, meter for absence of voltage.

Do not open a vent before the isolation valves are shut, and do not pull the disconnect on a running FPS-1650 — that skips the stop-and-depressurize and leaves the air side charged.

Energy source	Isolate	Verify
Electrical	Open the disconnect feeding the generator and lock it out. On the FPS-3250 and FPS-5000, do the same at the external compressor and dryer — they are separate circuits.	Test for absence of voltage with a meter at the point of work, and prove the meter before and after. A dark display tells you the screen lost power; it does not prove the conductors you are about to touch are dead.
Compressed air	FPS-3250 / FPS-5000: close the main air input ball valve. That leaves the feed compressor, any air receiver, and the piping between them at full pressure — isolate and bleed those at the compressor if your work reaches them. FPS-1650: stop the unit first (that is what relieves the air side), then open the disconnect. On any model with auto air bypass, also close the bypass air inlet ball valve.	Vent the section and read 0 PSIG at its gauge — see the depressurizing procedure below. Closing a valve stops the supply; it does not empty what is already downstream of it.
Stored nitrogen	Close the nitrogen outlet ball valve and the tank ball valves, then bleed the tank and cabinet to atmosphere in a well-ventilated area. Note that the filter pressure relief valve does not do this — it vents the filter bowls and retains tank pressure by design.	0 PSIG at the storage tank gauge. Be aware that closing both the tank valves and the outlet valve traps nitrogen in the run between them with no relief path — treat that section as live until it is proven otherwise. If you cannot identify a bleed for the section you need to open, stop and contact South-Tek. Closing these valves on a system in service is a fire protection impairment — see below.
Riser pressure	The nitrogen outlet ball valve isolates the generator from the riser — it does not relieve riser pressure. To work downstream of it, close the AMD upstream of that section and drain the section per the site procedure.	0 PSIG on a gauge on the riser section you are actually opening. The cabinet gauge reads storage tank pressure and tells you nothing about the riser. This is the isolation most often missed — closing the outlet valve leaves full supervisory pressure sitting on the downstream side of it. And do not rely on a check valve: the one in the outlet assembly stops bypass air backfeeding into the generator's air side and does nothing to isolate the sprinkler system.
Stored electrical energy	Opening the disconnect does not instantly empty the power supply and the panel components.	After opening the disconnect, confirm the display is dark and allow the panel to discharge before opening it — then test for absence of voltage at the point of work.

⚠ Warning — Standby is not Off, and Stop is not isolation The generator starts on its own whenever tank pressure falls to the cut-in setpoint. A unit that has been silent for twenty minutes can start while your hands are inside it. Holding the Stop button is a control action; it does not isolate any energy source. Open the disconnect, lock it out, and verify absence of voltage before working inside the cabinet.

Depressurizing before opening a pressure component

Isolate first, then vent, then verify — and the order of the valves matters.

Model / build	Procedure
FPS-1650	Stop the unit; it depressurizes on stop. Open the disconnect and lock it out — the internal compressor is the air source, so this is the isolation. Confirm the gauge after the coil reads 0 PSIG before opening anything.
FPS-3250 / FPS-5000 current white-ASCO build	Stop the unit, close the main air input ball valve first, then open the tagged filter pressure relief valve, then open the disconnect and lock it out. That valve order matters — opening the relief valve while the inlet is still open just dumps live feed air and depressurizes nothing. The relief valve vents all three filter bowls at once and retains tank pressure. Confirm 0 PSIG at the filter/regulator gauge and that venting has stopped. Leave the relief valve open while you work, and close it before returning the unit to service.
FPS-3250 / FPS-5000 legacy black-bowl build	Stop the unit, close the air inlet, then open the air service valve after the regulator slowly to relieve to 0 PSIG, then open the disconnect and lock it out. Leave the service valve open while you work and close it before returning to service.

⚠ Warning — never use a component as a bleed Do not crack a filter bowl, a fitting, or a body clamp to find out whether a section is still pressurized. If you cannot positively identify the vent point for a section, stop and contact South-Tek. Loosening a retained component under pressure is how people get hurt on this equipment.

Fire protection impairment

This generator is part of a fire protection system. Anything that stops nitrogen reaching the riser — closing the outlet valve, closing the tank valves for a leak test, taking the unit out of service for a filter change — is a system impairment, even though the sprinkler piping itself is untouched.

▲ Attention — before you close a valve on a system in service Follow the site impairment procedure: tag it; notify the building owner or facility representative and the alarm monitoring company — that is the notification that stops a false dispatch when the supervisory signal trips — and, where required, the authority having jurisdiction and the property insurer. Keep the window as short as the work requires, and restore and verify before you leave. Reopen the tank and outlet valves, confirm the tank recovers to the cut-out setpoint, confirm the outlet gauge follows, and confirm the unit returns to Standby. A diagnostic that ends with the nitrogen supply valved off is worse than the fault you went to investigate — the riser bleeds down with nobody watching.

A system sitting in bypass is a related case: it is supervised, but with air rather than nitrogen, so it is not protected from corrosion. Bypass during the 30-minute fill test is normal. Bypass at any other time should be investigated. Alarm meanings are in Operation and Alarms.

Pressurized gas and relief valves

Never disable, plug, adjust, or bypass a safety relief valve. The nitrogen storage tank is protected by a relief valve set at 135 PSI / 119 SCFM, and the FPS-1650 carries a further 125 PSI / 110 SCFM valve on the compressor side — 115 PSI on CE-configured units, which is a different build, so check the unit rather than assuming the figure. If a relief valve is lifting, the cause is upstream — investigate it, do not restrain the valve.
Never let pressurized gas exhaust from an unsecured hose. A loose hose whips. If one bursts in service, close the isolation valves if it is safe to reach them and shut the unit down.
FPS-3250 and FPS-5000 — keep feed air within 100–125 PSIG. Feed air outside that range can damage the generator, and that damage is not covered under warranty. The FPS-1650 makes its own air and has no feed-air connection.
The purity sample port vents nitrogen into the room. Ventilate the space, open it only for the reading, and close it immediately afterwards.
Use approved replacement parts that meet or exceed the original specification. Non-factory filter elements and fittings are a warranty and a safety issue.

Electrical safety

Disconnect supply power before any electrical work — and verify absence of voltage at the point of work with a meter, not by looking at the display.
Land incoming power at the cabinet's 20 A power entry module, not directly onto the internal power supply. Final connection is a qualified electrician's work.
Supply voltage is factory configured and cannot be changed after build. Read the product information label and confirm the incoming service matches before energizing.
The control panel is a UL 508A open-type industrial control panel. The cabinet is its enclosure — do not operate the unit with the panel exposed, and close it up before restoring power.
FPS-3250 and FPS-5000: the external compressor and dryer are on their own circuits with their own disconnects. If the compressor is three-phase, verify rotation before first start — running it backwards damages it.
Keep the touchscreen and panel area clear. Do not spray soapy leak-check solution on or near electrical components.

Environment, handling, and installation

Install indoors in a nonhazardous, well-ventilated location at 40–100°F, on a hard flat surface rated for the weight with margin. The room must not be sealed off from normal air changes.
Store the unit before installation at 60–80°F, dry, upright or in its crate as shipped. Never place or stack objects on top of it.
Unbolt the unit from the crate before lifting it out, set it down, and move it with a floor jack. Do not walk a tall cabinet on its corners.
FPS-1650: remove the four painted bolts underneath the cabinet before startup — they lock the compressor's vibration isolators for shipping, and running the unit with them in place transmits vibration into the cabinet.
Keep gas lines dry during hook-up so moisture does not enter the generator. Water carried into the PSA beds is permanent damage and is not covered under warranty.
Leave the clearances the installation requires — service access at the front and the left side, ventilation clearance all round, and working space at the electrical connection per NEC 110.26. Full detail is in Site and Utility Requirements.

If something goes wrong

Situation	What to do
A hose bursts or a line lets go while running	Stay clear of the loose end. Close the isolation valves only if you can reach them safely, shut the unit down, and let the section vent before approaching it.
Audible leak inside the cabinet	Hold Stop, close the nitrogen outlet valve, isolate the air side for your model, then depressurize and verify zero before opening anything. Do not chase a leak with the system live.
Someone feels dizzy or breathless in the room	Most fatalities in oxygen-deficient atmospheres are would-be rescuers. Do not enter a suspected oxygen-deficient space to attempt a rescue without self-contained breathing apparatus and trained assistance. Call emergency services, ventilate the area from outside, and shut off the gas supply only if that can be done safely from a safe location. If the casualty is already out, move them to fresh air and keep them there until help arrives.
A relief valve is lifting	Do not restrain or plug it. Shut the unit down, isolate, and find the upstream cause before restarting.
You are not sure the system is depressurized	Then it is not. Stop, and contact South-Tek before opening anything.
The system has been left valved off or in bypass	Treat it as an active impairment. Restore supervision, verify the unit returns to Standby, and notify whoever holds the impairment tag.

Warranty and unauthorized modifications

Do not modify the equipment, defeat a safety device, or operate it outside its published specifications.
Do not change the cut-in and cut-out setpoints or the control programming without South-Tek's involvement. The program is proprietary and password-protected, and unauthorized changes void the performance specification and the warranty.
Use only approved replacement parts. Non-factory filter elements may void the warranty.
Damage from out-of-spec feed air — wrong pressure, high temperature, or a dew point that lets moisture reach the PSA beds — is not a warranty repair.
Only the designed purpose. These units make nitrogen for fire protection systems; do not repurpose them.

Manual download

FPS-1650, FPS-3250, and FPS-5000 O&M Manual

Need help? South-Tek Systems Service — Phone: (910) 415-1880 · Open a support ticket at support@southteksystems911.zendesk.com or through the Help Center. Field service is typically scheduled about two weeks out, and remote startup and troubleshooting support is available.