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3. Accuracy of pressure gauges typically used in the fire sprinkler industry can vary as much as
8-12 psi (.55-.83 bar) (See Operational Information (section 1.d.) for Sprinkler System Gauge
Accuracy).
Determine the operating pressure for all AMDs connected to a single nitrogen generator. The operating
pressure must be the same for all AMDs.
NOTE: AMDs operating at different operating pressures will have an adverse effect on the operation and
can reduce the service life of the nitrogen generator.
Initial Setting of AMDs (Revised numbering)
1. Close the valves to all accelerators on the sprinkler systems (if installed).
2. Systems not being checked - Close all the AMD valves.
3. System being checked - Verify the AMD fast fill (bypass) valve is open and the inlet/outlet
(regulated) valves are closed.
4. Use the flow meter ball valve to relieve gas from nitrogen/air supply line to sprinkler system’s
AMD allowing the nitrogen generator to cycle on.
5. Set nitrogen generator to bypass (air only mode) and fast fill sprinkler system with air to 3-5 psig
(.2-.3 bar) below operating pressure.
6. Change nitrogen generator to nitrogen mode, open the AMD inlet/outlet (regulated) valves, close
AMD fast fill (bypass) valve and complete filling of sprinkler system.
7. When sprinkler system air pressure gauge reaches desired system operating pressure:
a. Slowly decrease AMD regulator pressure (turn counterclockwise) until pressure indicated
on HMI transitions from steady pressure to climbing pressure, the AMD regulator should be
properly set.
8. Verify AMD operating with nitrogen generator using AMD Operation with nitrogen generator
verification procedure.
9. Repeat 4 thru 8 for each additional AMD connected to the nitrogen generator.
AMD Operation with Nitrogen Generator - Verification
1. Systems not being checked: Close all the AMD valves.
2. System being checked: Verify the AMD fast fill (bypass) valve is closed and the inlet/outlet
(regulated) valves are open.
3. Set the cut-in (turn-on) pressure of the nitrogen generator to 3-5 psig (.2-.3 bar) below the AMD
set pressure (See section 6.g., in the Maintenance Section for the Nitrogen Generator Pressure
Adjustment Procedure).
4. Slowly drain 3-5 psi (.2-.3 bar) of pressure out of the sprinkler system.
5. Use the flow meter ball valve to relieve gas from nitrogen/air supply line to sprinkler system AMDs
allowing the nitrogen generator to turn on.
6. Allow the sprinkler system to fill with nitrogen while monitoring the pressure on the HMI LCD
display in the nitrogen generator.
a. As pressure increases in sprinkler system and on the HMI LCD display (through the AMD),
the pressure increase will be gradual.
b. When the sprinkler system operating pressure reaches the AMD set pressure and the AMD
closes:
i. The pressure on the sprinkler system air gauge will stop rising.
ii. The pressure on the pressure HMI LCD display will increase at a rapid pace until the
nitrogen generator turns off (cut-out pressure).
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