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Sequence of Operation
Once in service, the nitrogen generator requires no additional intervention to function properly. Nitrogen
generator settings should not be altered without consulting ECS and the unit should not be powered down
or bypassed for any reason other than a service or maintenance procedure as detailed in the Maintenance
Section. The nitrogen generator operates in two (2) modes, Nitrogen Inerting Mode and Supervisory Gas
Mode.
NOTE: The nitrogen generator incorporates an 8-second delay upon nitrogen generator start for
protection of the integral air compressor.
Nitrogen Inerting Mode
The application of supervisory nitrogen gas to a dry pipe or preaction fire sprinkler system using the ECS
Dry Pipe Nitrogen Inerting (DPNI) protocol which is fundamentally different than the traditional
application of compressed air as a supervisory gas. Because the DPNI protocol uses a process called “fill
and purge breathing” it requires small (3-5 psig (.2-.3 bar)) supervisory pressure fluctuations in the fire
sprinkler system(s) to remove oxygen before it can cause corrosion.
• The nitrogen generator and compressor will cycle on to increase the pressure in all fire sprinkler
systems connected to the nitrogen generator.
• Once the high-end pressure of the breathing cycle is reached the air compressor and nitrogen
generator will turn off and the fire sprinkler system(s) are allowed to depressurize gradually
through the oxygen removal vent(s).
• Once the low-end pressure of the breathing cycle is reached, the air compressor and nitrogen
generator automatically turn on to repeat the process.
• The high-end/turn-off pressure is determined by the pressure setting of the fire sprinkler
system(s) air maintenance device (AMD) and the low-end/turn-on pressure is determined by the
nitrogen generator’s integral pressure transducer.
• The air compressor and nitrogen generator are simultaneously cycling the pressure in all fire
sprinkler system(s) by 3-5 psig (.2-.3 bar) during each cycle. This will result in longer run times of
the air compressor and nitrogen generator than a traditional air compressor configured to supply
supervisory gas.
• The DPNI “fill and purge breathing” protocol described above is performed for a fourteen (14) day
period, during this time the system pressure will fluctuate between the high-end and low-end
breathing pressures.
• Once the fourteen (14) day inerting period is complete and the ball valve on the Standard Vent is
closed, the SMART Vent is automatically closed, or the AdvancedIQ Vent is automatically closed;
and the run frequency of the air compressor and nitrogen generator is reduced.
It is important to remember that closing the vents will not affect the runtime of the air compressor and
nitrogen generator. It will only affect the frequency that the air compressor and nitrogen generator will
run. The nitrogen generator and air compressor are designed to run for up to two (2) hours at a time when
filling all the systems with 3-5 psig (.2-.3 bar) of high purity nitrogen.
If air compressor and nitrogen generator runtimes are greater than four (4) hours, contact ECS
immediately.
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