FPS-500 and FPS-900 Operation, Alarms, and Maintenance – South-Tek Systems

This article applies to South-Tek Systems N2-BLAST FPS-500 and FPS-900 fire protection nitrogen generators.

Use this article for normal operating behavior, common alarm conditions, leak detection guidance, and routine maintenance for the FPS-500 and FPS-900.

Normal operation

In Running mode, the unit is producing nitrogen and supplying it to the storage tank. The system automatically enters Standby mode when the tank is fully pressurized, typically at approximately 65 to 75 PSIG.

The unit remains in standby until tank pressure falls by approximately 7 to 10 PSIG.
Once pressure drops enough, the system automatically resumes nitrogen generation.
This automatic cycling is part of normal operation.

Controller functions

The controller provides access to several basic operating functions and status screens.

Filter Change Reset: After filter replacement, press and hold the down button for 7 seconds to reset the filter timer. The controller will confirm with an audible beep and a filter reset message.
BlastOff simulation: The controller can simulate a BlastOff alarm for testing. This requires the passcode and is used to confirm proper alarm contact operation.
Next button navigation: The controller can display filter hours, program version, ambient temperature, and other applicable sensor or setpoint information.

Stopping the system

Close the gas outlet valve on the nitrogen storage tank.
Allow the system to stop automatically once it reaches the cut-out pressure of approximately 65 to 75 PSIG.
In an emergency, move the On/Off toggle to the Off position to shut the unit down immediately.

Alarm conditions

Power loss alarm

The Power Loss Alarm activates if the nitrogen generator loses power for any reason. This causes the alarm contact to trigger.

Bypass alarm

During the 30-minute fire protection piping system fill test, the unit can be placed in manual bypass mode by turning the handle on the left side of the cabinet.

When the handle is in bypass mode, the unit generates an audible and visual bypass alarm.
On the FPS-900, a dry contact is also available for external notification such as a building monitoring system.
The alarm clears when the handle is returned to normal run position.

BlastOff alarm

The BlastOff feature is intended to detect potential leaks or nitrogen overdemand conditions.

The alarm can trigger an audible buzzer, controller indication, and alarm contact.
On the FPS-900, BlastOff can also provide a dry contact signal to a building management system.
Power cycling the unit resets the alarm, but repeated resets without addressing the cause can shorten generator life.

Leak checking

The BlastOff system provides early warning for potential leaks, but physical leak checks are still important.

Listen for leaks and use soapy water around connection points.
If a leak is found, isolate the area and relieve pressure before making repairs.
If no leak is obvious, isolate sections of the system and monitor for pressure loss.

Checking for leaks between the generator and tank

With the unit powered on, close both ball valves on the nitrogen tank and note the tank pressure.
Allow the system to continue running. It should reach standby mode within 10 minutes or less.
Wait 5 minutes.
If the system remains in standby, the leak is likely after the nitrogen generator.
If tank pressure changes, the leak is likely within the storage tank fittings.
If tank pressure does not change, check the building piping for leaks.
If the system returns to run mode, the leak is likely within the cabinet or lines back to the tank.

Routine maintenance

Always power down the system before performing maintenance. Remove the front cover to access the filters.

Annual filter replacement kit: FRP-007
Air pre-filter: Replace once per year or every 1000 hours, whichever comes first.
Particulate and coalescing filters: Replace once per year or every 1000 hours, whichever comes first.

Air pre-filter service

The integrated compressor includes an intake pre-filter to keep particles out of the compressor housing.

Remove the pre-compressor filter cap by twisting it clockwise.
Remove the old element.
Clean the filter bowl with a clean, dry cloth.
Install the new element.

Air filter replacement

Turn off the unit and open the front cabinet door.
Locate the air filters on the bracket in the middle of the cabinet.
Make sure the filters are completely depressurized by checking the pressure gauge.
Remove the filter bowls by turning them counterclockwise.
Rinse debris out of the bowls with warm water.
Dry the bowls with a clean, dry cloth.
Replace the old O-rings with the replacements from the kit.
Replace the particulate and coalescing elements.
Reinstall the bowls to their corresponding filter housings.
Reset the filter timer on the controller by holding the down button for 7 seconds.
Power the unit back on and check the filter bowls for leaks.

When to get support

Contact support if the system will not enter standby, repeatedly returns to run mode without demand, continues to trip BlastOff, or shows signs of internal leakage or recurring alarm conditions.

Manual downloads

Need additional support?

Phone: (910) 415-1880
Email: support@southteksystems911.zendesk.com