Applies to: BlastOff and SMART-Trak on South-Tek N2-BLAST fire protection nitrogen generators. Which features your unit has depends on its model — see the availability table below.
Two things with two jobs. BlastOff is the alarm set: it watches how the generator is behaving and tells you when something is wrong. SMART-Trak is the display and record: it shows you what the system is doing now, keeps the history, and carries the BlastOff alarms on screen.
Between them they answer the question that brings most people to this article — my generator is showing something, what is it telling me? Start by working out which display you are looking at.
Which display are you looking at
Three different displays are in service across the N2-BLAST line, and they use different wording for the same conditions. On the two character displays the keypad is the quickest way to tell them apart. Match the one in front of you before you look anything up.
| Display | How to recognize it | Reads like |
|---|---|---|
| Short-code display | Character display with no keypad beneath it. Status abbreviated to four or five characters. | Run Stdby FAlm BOff |
| Spelled-out display | Character display with a keypad beneath it — SET, F1, F2, F3, ENT. Status spelled out as whole words. |
rUnnInG StAndby FILT ER CHANGE BLASTOFF 9H.RUN |
| SMART-Trak screen | Color touchscreen on the cabinet door, with a piping graphic and a pressure readout. | Running Bypass Purity Issue Dryer Issue |
▲ Attention — the same fault reads differently on each display A filter alarm reads FAlm on one controller and FILT ER CHANGE on another. A runtime alarm reads BOff on one and BLASTOFF 9H.RUN on another. They are the same condition. If you cannot find your exact wording below, look for the condition rather than the characters.
⚠ Warning — a silenced alarm is not a cleared alarm Silencing an alarm stops it announcing itself. The condition is still there. On SMART-Trak a silenced alarm puts a line through the bell icon; on a character display it simply stops flashing. Either way, a system that looks calm may be a system somebody acknowledged and walked away from. Before you leave site, confirm the condition is resolved rather than muted — and if the building relies on the dry contact to the fire alarm or BMS, confirm with South-Tek what that contact does while an alarm is silenced before you count on it.
Reading the controller display
| Condition | Short-code | Spelled-out | What it means |
|---|---|---|---|
| Producing | Run | rUnnInG | Normal. The generator is making nitrogen and filling the storage tank. |
| Satisfied | Stdby | StAndby | Normal. Storage is at pressure and the generator is waiting for pressure to fall before it starts again. This is where a correctly sized system sits most of the day. |
| Filter alarm | FAlm | FILT ER CHANGE | 1,000 run hours or 12 months, whichever comes first. Not a fault — a service reminder. Change the filters and reset it. See Annual Filter Replacement (FRP-007). |
| Runtime alarm | BOff | BLASTOFF 9H.RUN | BlastOff I. The generator has run more than 9 hours continuously. Something is consuming nitrogen faster than the generator can make it. See below. |
Reading the SMART-Trak screen
SMART-Trak shows the system status, the nitrogen storage pressure, and a piping graphic with a status marker on each major component. Read the status line and the pressure together. Pressure on its own means nothing until you know what this system was commissioned to — that figure is set by the dry pipe valve, and a system running correctly at 40 psi is as healthy as one at 75.
| Status | What it means | What to do |
|---|---|---|
| Running with green markers | Normal production. Everything checks out. | Nothing. |
| Charge Fillers | A startup state. The system is bringing itself up to pressure — you will see this at 0.0 psi after a restart. | Let it come up. If it does not leave this state, treat it as a fault and call Tech Support rather than power cycling it repeatedly. |
| Bypass | BlastOff II. The generator has been bypassed and the system is running on compressed air. The sprinkler system stays pressurized and its pressure stays supervised by the building fire alarm exactly as before. What has stopped is the corrosion protection — and bypass air is both oxygen-rich and wetter than what the generator delivers, which is the corrosion mechanism in full. | Find out why, restore the generator, and return the system to nitrogen. Record how long it was on air and tell the owner, then re-check zone purity rather than assuming it recovers on its own. See How Do I Manually Activate Bypass Mode. |
| Purity Issue | BlastOff IV. Nitrogen coming out of the generator has fallen below 98% — the alarm threshold, which sits below the output specification. | This is the generator, not a zone. Call Tech Support — do not chase it as a zone purity problem. |
| Dryer Issue | BlastOff III reporting a fault on the air dryer. BlastOff III covers more than the dryer — this is one of the conditions it catches. | Wet feed air shortens sieve bed life. Deal with it promptly. |
Run time is the leak detector
A nitrogen generator runs when the system needs gas. Every dry system leaks a little, and making that up is the generator's job — so run time tracks how much gas the system is losing, which makes it a useful leak indicator long before a pressure switch notices anything.
It is not only leaks. The generator also runs after anything that takes gas out of the system on purpose: an inspector's test, a trip test, a drain-down, a head replacement, tenant work, or the initial fill. Routine inspection and testing is the most common reason a generator runs long, and it is not a fault. Ask what was done to the system before you go looking for a leak.
| Run time | Reading |
|---|---|
| 3 to 5 hours a day | Normal. |
| Climbing, month over month | A leak that is getting worse. Investigate before it becomes a low air alarm — this is the whole point of tracking run time. |
| More than 9 hours continuous | BlastOff I alarms. The generator is not keeping up. |
▲ Attention — the alarm measures continuous run time, not daily total A leak big enough to run the generator eight hours a day in short repeated cycles may never trip BlastOff I, because no single run reaches nine hours. Do not wait for the alarm. Track run time as a trend — a system that used to run four hours a day and now runs seven is telling you something even though nothing has alarmed.
What actually causes a BlastOff I alarm, roughly in the order you should consider them:
- The system was recently opened, drained or tested. Check this first. It costs nothing and it is the most common answer.
- A leak in the fire protection piping. The most common genuine fault.
- Demand beyond what the generator can supply — zones added since commissioning, APS units set too far open, or a generator sized for a smaller system.
- A leak inside the generator cabinet or in the nitrogen piping at it.
- The generator is not making gas properly. Loaded filters, low feed air pressure, a compressor fault, or cold inlet air will all stop it keeping up.
- A pressure switch or transducer that has drifted, so the generator never sees the standby setpoint and never stops. This one will read as an internal fault on the test below, which is the correct outcome — it is internal.
Narrowing it down: inside the cabinet, or out in the building
⚠ Warning — read this before you touch the outlet valve The test below isolates make-up gas from the sprinkler system, on a system you already know is losing gas faster than the generator can replace it. That is exactly the system whose pressure falls fastest. If it falls to the trip point, a dry pipe valve operates and the piping fills with water.
Before you close anything: notify the building owner or their impairment coordinator and the alarm monitoring company, and let them tell you whether they want it treated as an impairment — that is their call, not yours and not South-Tek's. Know whether you are on a dry or a pre-action system before you start; they do not behave the same way.
During the test: watch the system pressure gauge, not the generator. Reopen the valve immediately if system pressure drops more than a few psi or starts approaching the low air setpoint. Do not walk away, do not take another call, and tag the valve so nobody else finds it shut. Reopen it when you are done — the answer takes minutes, not an afternoon.
Before you close anything: notify the building owner or their impairment coordinator and the alarm monitoring company, and let them tell you whether they want it treated as an impairment — that is their call, not yours and not South-Tek's. Know whether you are on a dry or a pre-action system before you start; they do not behave the same way.
During the test: watch the system pressure gauge, not the generator. Reopen the valve immediately if system pressure drops more than a few psi or starts approaching the low air setpoint. Do not walk away, do not take another call, and tag the valve so nobody else finds it shut. Reopen it when you are done — the answer takes minutes, not an afternoon.
With that in hand: close the nitrogen outlet valve at the generator and watch whether the generator can build pressure on its own and reach standby.
| What the generator does | What it means | Where to go |
|---|---|---|
| Builds pressure and reaches standby. | The generator itself is healthy. The demand is downstream of it — either a leak in the fire protection piping, or more demand than this generator can supply. | See the two rows below — they look identical at this point and need separating. |
| Still cannot build pressure and keeps running. | The problem is inside the cabinet or in the nitrogen piping right at it. | Call Tech Support. Do not open the cabinet. |
A generator that builds pressure has told you the fault is downstream, but it has not told you whether that is a leak or a demand problem — both look the same from the generator. Separate them before you spend a week chasing a leak that is not there:
| Check | Points to |
|---|---|
| Has anything been done to the system recently? Inspector's test, trip test, drain-down, head replacement, tenant fit-out, or an initial fill. | Nothing is wrong. The generator is refilling the system, which is its job. Let it finish and check run time again over the following week. |
| Have zones been added, or was the generator sized for a smaller system? Compare the system volume and zone count against what this model is rated for. | Demand exceeds supply. No amount of leak hunting will fix it. |
| Are the APS flow settings correct for each zone? One left too far open vents nitrogen continuously. | Over-purging. See APS Flow Settings Reference. |
| None of the above, and run time has been climbing. | A leak. Go to System Leak Check Procedure. |
What each BlastOff tier does, and which one you have
| Tier | Fitted to | What it watches |
|---|---|---|
|
BlastOff I Leak Detection Alarm |
Standard on every N2-BLAST. | Continuous run time. Alarms after more than 9 hours continuous. This is the one everybody has and the one that catches leaks. |
|
BlastOff II Auto Air Bypass Alarm |
Standard on FPS-1650 and larger. Not fitted below that — on a smaller unit there is no bypass alarm at all, so silence proves nothing. | Whether the generator has been bypassed onto compressed air, and how long it has been that way. The bypass history is logged, so you can see periods when the system was not on nitrogen. |
|
BlastOff III Early Warning System |
Standard on FPS-1650 and larger. | The generator's own components — the dryer among them. Catches equipment problems before they take the generator out, and narrows down where a fault sits. |
|
BlastOff IV Onboard Purity Alarm |
Optional on all models. | Nitrogen purity at the generator outlet. Alarms below 98% and trends purity over time. |
⚠ Warning — no purity alarm does not mean the generator is in specification A current N2-BLAST is specified to produce 98.5% nitrogen or better. BlastOff IV alarms below 98%. That gap is deliberate — an alarm should sit below the spec, not at it — but it means a generator sitting steadily at 98.2% is out of specification and will never alarm. If purity matters on the job, read the actual number off the trend rather than taking the absence of an alarm as confirmation.
ℹ Note — BlastOff IV watches the generator, not your zones BlastOff IV alarms on the gas leaving the generator. It says nothing about what any sprinkler zone is reading. Zone purity is a separate measurement made at the zone, and the two go wrong for different reasons — see AutoPurge and Quick-Check Overview. A generator producing to specification with a zone reading low is usually a purge or sampling problem rather than a generator problem: the zone may still be driving its trapped air out, the sample line may be on the wrong port, or the reading may have been taken too early.
Remote monitoring and history
Where SMART-Trak is fitted and the site has provided network connectivity to it, the same screen can be viewed remotely on a mobile device. It carries:
- Nitrogen tank pressure and run hours, live.
- Run time averages — daily, monthly and annual.
- Average leak rate over the same periods, which is what turns run time into a trend you can act on.
- Filter and preventive maintenance tracking, so the service reminder does not depend on somebody noticing a code on a display.
- BlastOff alarm history, including time spent in air bypass.
The history is the part worth using. A single reading tells you almost nothing. Run time creeping up over three months is evidence — enough to justify a leak search, and enough to show the building owner why it is needed.
Related articles
- N2-BLAST Fire Protection Systems Overview
- System Leak Check Procedure
- Annual Filter Replacement (FRP-007)
- How Do I Manually Activate Bypass Mode
- AutoPurge and Quick-Check Overview for N2-BLAST Systems
- PLC Fatal Error: Re-initialization and Parameter Restore
- Fire Alarm and BMS Wiring for FPS Generator Dry Contacts
- FPS-500 and FPS-900 Operation, Alarms, and Maintenance
- FPS-1650, FPS-3250, and FPS-5000 Operation, Alarms, and Maintenance
- FPS-10000, FPS-16500, and FPS-22500 Operation, Alarms, and Maintenance
Need help? Have the model and serial number and what the display is showing ready. South-Tek Systems Service — Phone: (910) 415-1880 · Open a support ticket at support@southteksystems911.zendesk.com or through the Help Center.