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iv. Push knob back into regulator until it clicks into place.
v. Once the nitrogen generator system has been commissioned, open the isolation ball valve
on the vent assembly, turn the green power switch on the electric control box to the ON
position and push the orange VENT button. The button should now be illuminated.
vi. The SMART Vent is now open and actively venting oxygen from the fire sprinkler system.
It will remain open for approximately fourteen (14) days.
vii. At the conclusion of the fourteen (14) day DPNI process, the orange VENT button will
extinguish and the vent will automatically close.
viii. If the sprinkler system actuates or another event introduces oxygen to the sprinkler
system press the orange VENT button to automatically restart the oxygen venting cycle.
Low Pressure Valves
When connecting a nitrogen generator to a low-pressure valve, additional considerations need to be
evaluated. Due to the inherent operating pressures (i.e. 20 psi (1.4 bar) or below), the operational
tolerances are tighter which reduces the pressure range for the “fill and purge” pressure cycling to
operate.
1. Typical trip pressure for low-pressure valve is 7 psi (.5 bar).
2. Typical low air alarm pressure for low pressure valve is 10 psi (.7 bar).
3. Typical operating pressure for a low-pressure valve is 13 psi (.9 bar) minimum and 18 psi (1.2 bar)
maximum.
Based on this information, the “fill and purge” breathing cycle needs to be reduced to a 3 psi (.2 bar)
breathing range and determine the vent orifice size based on a 3 psi (.2 bar) breathing range.
1. Adjust the sprinkler system air maintenance device (AMD) to 18 psig (1.2 bar).
NOTE: If AG-675 or AG-975 is used on a single sprinkler system without an air maintenance
device (AMD), set the nitrogen generator cut-out (turn-off) pressure to 18 psig (1.2 bar).
2. Set the nitrogen generator cut-in (turn-on) pressure to 15 psig (1 bar).
Check the operation and interaction between the nitrogen generator and the sprinkler system air
maintenance device (AMD).
NOTE: ALL pressures are measured from the Sprinkler System Air Gauge, unless otherwise indicated.
1. Check the turn-on function
a. Reduce sprinkler system pressure to 15 psig (1 bar) to check the turn-on function.
b. If nitrogen generator automatically turns on, the nitrogen generator and sprinkler system air
gauge are in alignment.
c. If nitrogen generator does not automatically turn on, the nitrogen generator and sprinkler
system air gauge are NOT in alignment.
i. Verify pressure indicated on nitrogen generator HMI.
Example: Nitrogen generator HMI indicates 16 psig (1.1 bar) and the sprinkler system air
gauge indicates 15 psig (1 bar), 1 psig (.1 bar) difference between nitrogen
generator HMI and sprinkler system air gauge.
ii. Change the nitrogen generator cut-in (turn-on) pressure to align with pressure indicated
on nitrogen generator HMI.
Example: Change cut-in (turn-on) pressure form 15 psig (1 bar) to 16 psig (1.1 bar).
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