Page 12 - NG-1 100, NG-1 250, NG-1 500 - Wall-Mounted Nitrogen Generator System Installation Manual

A sprinkler system using a low-pressure valve with a 200 psi (14 bar) gauge indicating a 15 psig (1 bar) operating pressure can actually be operating between 9 psig (.6 bar) and 21 psig (1.4 bar); which could be close to the low-air alarm/trip pressure of the sprinkler system.
The digital controller in the TYCO Nitrogen Generator used to turn-on and turn-off the nitrogen generator is accurate to < ±1.5%.
To ensure proper operation of the sprinkler system and the nitrogen generator, calibrate the sprinkler system operating pressure to the turn-on pressure of the nitrogen generator using the Air Maintenance Device (AMD) Pressure Adjustment Procedure in the Maintenance Section of this manual.
The procedure aligns the sprinkler system operating pressure to the turn-on pressure of the nitrogen generator; reducing the potential of the nitrogen generator turn-on pressure to be set near the low-air alarm/trip pressure of the sprinkler system.
Sprinkler System Air Maintenance Device
Dry pipe and preaction fire sprinkler systems are to be configured to use a single air maintenance device (AMD) for each dry pipe and preaction fire sprinkler system in accordance with NFPA 13.
• Applications where multiple fire sprinkler systems are served with a single AMD has been known to cause nitrogen generators to short cycle due to the air restriction that the AMD imposes on the nitrogen supply line. Short cycling of the nitrogen generator can cause damage to the system components and may affect the manufacturer’s warranty.
AMD operation is directly affected by the inlet pressure to the AMD. To ensure the AMD operates properly with the nitrogen generator, use the Air Maintenance Device (AMD) Pressure Adjustment Procedure in the Maintenance Section of this manual.
Fire Sprinkler System Leak Rates
The leak rate of a dry pipe or preaction fire sprinkler system will have direct effect on the nitrogen generator run frequency or on/off cycles. The maximum allowable leak rate in a fire sprinkler system as defined by NFPA-13 is 1.5 psig (.1 bar) within a 24-hour period. The design specifications of TYCO Nitrogen Generators is based on 6.0 psig (.4 bar) leak rate within a 24-hour period. Sprinkler systems with a leak rate in excess of 6.0 psig (.4 bar) within a 24-hour period will cause the nitrogen generator run frequency to increase resulting in a greater wear on system components and a potential reduction in the service life of the nitrogen generator. Sprinkler systems with a leak rate greater than 6.0 psig (.4 bar) in 24-hours must be repaired to ensure the anticipated service life of the nitrogen generator is met.
NOTES: The run frequency of the nitrogen generator in this chart is based on nitrogen generator operation outside of the 14-day nitrogen inerting process with the vent closed.
Excessive cycle count could indicate an air compressor/nitrogen generator short cycling issue. Contact Johnson Controls before proceeding – visit the CONTACT US page at www.tyco-fire.com for the contact information by location.
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