Controller Status Codes — Run, Standby, Filter Alarm & BlastOff (FPS-500, FPS-900, BeerBlast 3KPH & 7KPH) – South-Tek Systems

Applies to: Units with the black rectangular controller — N2-BLAST® FPS-500, FPS-900 and FPS-900-RS, and BeerBlast™ / BrewBlast™ / N2-GEN™ 3KPH and 7KPH. Go by the controller in front of you, not by the model number — the same model shipped with different controllers over the years.

Does NOT apply to: units with the square, cream-colored legacy controller and a green display — FPS-650, FPS-1250 and earlier FPS-900 builds, and legacy beverage units of any size — 1KPH, 3KPH, 7KPH — built with that controller. See Resetting the Filter Alarm — Legacy Panasonic Controllers. Also does not apply to the touchscreen models (FPS-1650 and up) — see their operation and alarms article.

This article explains the status codes shown on the controller screen and what to do about each one. Use it as a quick reference when a customer or technician reports a code they do not recognize. Wording varies a little between builds and program versions — if what you see does not match a row below, photograph the screen and send it with your ticket.

ℹ Note — button labels vary In normal operation the status shows on the top line in red with run hours below it in green. On an alarm the second line carries the rest of the alarm text instead of the hours. The colors do not change in an alarm — top line red, second line green either way; it is the words that tell you the state. The five keys under the display carry different legends depending on the vintage of the unit — SET · NXT · − · + · ENT on some, SET · F1 · F2 · F3 · ENT on others. They are the same five keys, and on the F-legend builds the arrows are printed on the keys: F1 carries ▶, F2 carries ▼ (down), F3 carries ▲ (up). The filter reset is always the down key — the one marked − or ▼, sitting between the other two arrow keys. Do not press and hold SET while hunting for it: a 7-second hold on SET opens the passcode screen, which is the way in to the alarm test that deliberately trips the common alarm contact — the fire panel on a fire protection unit, whatever monitoring is landed on a beverage unit.

ℹ Note — older units Legacy units use a square controller with a green display and slightly different codes. See Resetting the Filter Alarm — Legacy Panasonic Controllers for that generation.

Status codes

ℹ Note — the alarms share one contact Bypass, BlastOff® and power loss — and, on the FPS-900, the filter alarm as well — all drive the same common alarm dry contact on these models. Where that contact is landed, the receiving system sees an alarm without knowing which one, and the display is what tells you. On a fire protection unit that receiver is the fire panel; on a beverage unit it is whatever monitoring the site has, if any. If a monitoring company reports an alarm and the customer says nothing is wrong, get a photo of the screen.

Filter alarm — replacing filters and resetting the timer

Filters are replaced annually or at 1,000 run hours, whichever comes first. To reset the timer, press and hold the down key — marked − or ▼ — until you hear the beep and the display shows FILTER RESET, about 7 seconds. If it does not take, release and repeat. No passcode is needed.

The reset also pulses the common alarm contact for about one second, so on a fire protection unit tell the monitoring company before you do it, and confirm the panel is back to normal afterwards, or it gets logged as a fault. Changing the filters means shutting the generator down, isolating it, and proving the filter section is at zero on its own gauge — so on a fire protection unit the change itself is a fire protection impairment, not just the reset. Notify the building owner and the alarm monitoring company and tag the system before you shut the unit down, and before you leave confirm the unit is back in Run or Standby, the alarm has cleared at the panel, and the riser is at supervisory pressure. On a beverage unit this is not an impairment, but the generator is down for the length of the change and the storage tank draws down — coordinate with the venue so it does not land in service hours, and let the tank refill to Standby before judging dispense quality. The full filter replacement procedure for your equipment is here:

Fire protection (FPS-500, FPS-900): Annual Filter Replacement — FPS-500, FPS-900, FPS-900-RS, FPS-1650 (FRP-007)
Beverage (BeerBlast™ / N2-GEN™): Annual Filter Replacement — BeerBlast™ / BrewBlast™ (FRP-001)

▲ Attention Reset the filter timer every time the filters are replaced, even if the alarm had not yet appeared. Leaving it un-reset means the next reminder arrives at the wrong interval.

BlastOff® leak detection

BlastOff is a built-in leak detection feature. It activates when the generator cannot reach its cut-out pressure within about a 9-hour run, which usually points to one of the following:

A leak in the system — most commonly at a coupling or fitting, and by far the most likely cause.
A sizing or demand issue — consumption exceeds what the generator can supply. On a fire protection system that usually means the unit was sized to something other than the largest single zone; on a beverage system it means the draw exceeds the unit's rated output.
A leak inside the cabinet — if the generator cannot build pressure even with the storage-tank ball valves closed, the fault is on its own side — an internal leak or a compressor problem. Isolate at the tank ball valves, never at the generator's 3-way outlet valve, which does not isolate.

⚠ Warning — nitrogen displaces oxygen Everything below has you chasing a nitrogen leak. Nitrogen is colorless, odorless and displaces oxygen with no warning. Confirm leaks by listening and by spraying soapy water on the joints, never by feel. Isolate the area and relieve pressure before repairing anything, and bleed to atmosphere only in a well-ventilated space — never into a closet, cooler, pit, or sealed room, and never enter a confined space downstream of a leak or a vent without a calibrated meter reading 19.5% O₂ or higher.

Do the non-invasive check first. Listen along the pipe runs and spray soapy water on the connections at the generator, at the tank, and on the accessible fittings downstream. Most BlastOff alarms are found here, and it costs no downtime. Only if nothing turns up do you move to the isolation test below — that test does take the system out of service.

Working out whether the leak is inside the generator or downstream of it

⚠ Warning — on a fire protection system this is an impairment This test stops nitrogen reaching the riser while it runs. Notify the building owner and the alarm monitoring company, declare the impairment under the site's impairment program, and tag the system before you start. On a beverage unit this is not an impairment, but closing the tank valves stops gas reaching the dispense system — coordinate with the venue so it does not run during service. Keep the window to the length of the test, and restore the valves before you leave — a diagnostic that ends with the nitrogen supply valved off is worse than the leak you were chasing.

With the unit powered on, close both ball valves on the nitrogen storage tank — the inlet from the generator and the outlet to the system — and note the tank pressure. Use the ball valves on the storage tank, not the generator's outlet handle. The generator outlet is a 3-way valve that selects nitrogen or bypass — it does not isolate, so turning it puts the downstream system on compressed air instead of shutting the supply. Some builds carry a second 3-way valve on the air inlet: identify the valves by their placards on the unit rather than by counting them.
Let the unit run. It should reach Standby within about 10 minutes. If it has not reached Standby in 10 minutes, stop the test — go straight to the restore step, reopen both valves and put the system back. A unit that cannot make cut-out against closed valves has an internal leak or a compressor fault, and must not be left running against them.
Wait 5 minutes in Standby. If it holds, the leak is downstream of the generator — if the tank pressure moved, look at the tank fittings; if it did not, look at the building piping. Do the restore step before you go looking — do not leave the valves shut while you chase the piping.
If the unit returns to Run, the leak is inside the cabinet or in the lines back to the tank. Stop diagnosing — do not open the cabinet, and go straight to the restore step below to put the system back before you do anything else. This is an observation test run with the unit powered, so keep out of the cabinet while it runs. For any work at, in, or on the cabinet, open and lock the branch-circuit disconnect first, then isolate and bleed trapped pressure: the compressor starts under automatic control with no warning, and the filter bowls and manifold stay at full pressure. Wear safety glasses and hearing protection, and contact South-Tek if you are not equipped for this work.
Restore before you leave. Reopen both tank ball valves, confirm the tank recovers to its cut-out pressure, and confirm the unit returns to Standby. Confirm the downstream system is being supplied again — the riser on a fire protection unit, the dispense lines on a beverage unit. On a fire protection unit, confirm the alarm has cleared at the panel and the riser is at supervisory pressure, then clear the impairment tag and tell everyone you notified at the start.

Resetting a BlastOff alarm

Power-cycle the unit at its 15 A circuit breaker switch on the control panel (the On/Off toggle) — after you have found the cause, not before. On a fire protection unit the panel is already in common alarm from the BlastOff itself, and the power cycle drops the generator and holds that alarm in, so it is a fire protection impairment: notify the building owner and the alarm monitoring company first and tag the system. Before you leave, confirm the unit returns to Run or Standby, confirm the alarm has cleared at the panel, and confirm the riser is back at supervisory pressure. On a beverage unit none of that applies — just confirm the unit returns to Run or Standby and the tank refills.

⚠ Warning Do not repeatedly reset a BlastOff alarm without finding the cause. Continuous running shortens the generator's life, and on a fire protection system it means the sprinkler piping is not holding the nitrogen it is supposed to.

Need help? South-Tek Systems Service — Phone: (910) 415-1880 · Open a support ticket at support@southteksystems911.zendesk.com or through the Help Center. Have the unit's serial number, the run hours, and a photo of the controller screen to hand.

What you see	What it means	What to do
rUnnInG shown as RUN or RUNNING on some builds	The generator is operating normally and filling the storage tank. It stays in this mode until the tank reaches the cut-out pressure set on the mechanical pressure switch — 70 PSIG nominal, in a band of roughly 65–75 PSIG — then transitions to Standby.	Nothing, as long as it cycles. Run should end in Standby — a unit that stays in Run for hours is losing gas faster than it can make it. About 9 hours of continuous run trips the BlastOff® alarm, and a rising daily run-hour trend is the early warning before that.
StANdby shown as STDBY or STANDBY on some builds	The storage tank is at its cut-out pressure. The unit idles here until tank pressure falls 7–10 PSIG below that unit's own cut-out point, then returns to Run to refill the tank. Cut-out and cut-in are set on a mechanical pressure switch at the factory, and on a standard unit there is no setpoint screen to read — the values live on the switch itself.	Nothing, as long as it cycles. Standby is not off — the unit stays energized and the compressor restarts under automatic control with no warning, so open and lock the branch-circuit disconnect before opening the cabinet or working on any fitting. Record this unit's own cut-out and cut-in pressures off the storage-tank gauge; they are not field-adjustable. If it enters Standby well outside 65–75 PSIG, or the restart differential is not 7–10 PSIG, suspect the pressure switch — P/N 100317, carried in the critical spares kit — and call South-Tek before doing anything else.
FILT ER / CHANGE across both lines; shown as FALM on some builds	Filter alarm. The controller's 1,000-hour filter timer has expired. Filters are replaced annually or at 1,000 run hours, whichever comes first, so on a lightly used unit the calendar comes round before the alarm does. The unit keeps running — this is a maintenance reminder, not a fault.	Replace the filter elements, then reset the timer by holding the down key about 7 seconds until the beep and FILTER RESET. On a fire protection unit the change means shutting the generator down, so treat it as an impairment and notify first. Full procedure: FRP-007 for fire protection, FRP-001 for beverage.
BLASTOFF / 9H.RUN across both lines; shown as BOFF on some builds	BlastOff® leak detection. The unit has run continuously for about 9 hours — the 9H in the display string — without reaching its cut-out pressure. If a unit alarms at a noticeably different runtime, confirm the build with South-Tek rather than assuming a fault.	Treat it as a suspected leak. Do not power-cycle to clear it until you have found the cause. Nitrogen displaces oxygen and gives no warning — confirm leaks by listening and by spraying soapy water, never by feel, and work in a ventilated space. Start with that non-invasive check at the generator, the tank and the accessible downstream fittings; only if nothing turns up move to the leak-isolation test, which takes the system out of service. See also What BlastOff Means and What to Check First. On a fire protection unit the riser may be below supervisory pressure.
FILTER RESET	Confirmation that the filter timer has been cleared. It appears with an audible beep when the reset takes, while you hold the down (− / ▼) key for about 7 seconds after a filter change.	Nothing further on a beverage unit. On a fire protection unit the reset pulses the common alarm contact for about a second — confirm the panel is back to normal before you leave.
Air n2 bypass	The manual bypass handle on the left side of the cabinet has been turned. The generator stays online and running in this state. On a fire protection system the riser is being supervised with compressed air, not nitrogen, and corrosion protection is suspended for as long as it lasts. On a beverage system the product line is being pushed with compressed air — oxygen in the gas line oxidizes product, so treat it as urgent. Expected during the 30-minute fire protection piping fill test.	If it is not the fill test, investigate. Bypass is not a service mode and is not a substitute for nitrogen supervision while the unit is down. On a unit whose air comes from its own internal compressor, bypass delivers nothing once the unit is de-energized; on a unit fed by an external air compressor it keeps pushing air. Either way it is air, not nitrogen. Return the handle to the Nitrogen Out position and confirm the alarm clears. Check the red bypass indicator on the panel too; it is driven separately from the display. If the alarm and the handle position disagree, do not trust the handle — the position is sensed magnetically, so check the magnet and sensor on the valve, and call South-Tek if that does not resolve it: the sensor is a controller input.
(blank / dark display) Power loss	The unit has lost supply, so there is no screen to read — the controller is unpowered. The common alarm contact de-energizes and, where it has been landed, reports. On a fire protection unit this is the one that reaches the panel when nobody is on site, and it is also what happens every time a technician opens the disconnect for service.	Restore power and confirm the unit returns to Run or Standby. On a fire protection unit, opening the disconnect for service is a fire protection impairment: notify the building owner and the monitoring company first and tag the system, and before you leave confirm the alarm has cleared at the panel and the riser is back at supervisory pressure. On a beverage unit, check the storage-tank pressure when power returns — the tank draws down while the generator is off, and dispense quality suffers before the tank is empty. Let it refill to Standby before judging anything else.