Using Pressurized Nitrogen

The improper use of high pressure cylinders can cause physical damage to components, or personal injury, or cause stress that would lead to failure of components.

Typical Pressurized Gas Bottle
      
  1 Line Pressure
  2 Tank Pressure
  3 Tank
  4 Pressure Test Line to System
  5 Safety Valve
  6 Pressure Regulator
     
Parent topic: Refrigeration Maintenance

Safety Precautions

Observe the proper handling of cylinders:

  • Always keep protective cap on cylinder when not in use.

  • Secure cylinder in proper storage area or fastened to cart.

  • Do not expose to excessive heat or direct sun light.

  • Do not drop, dent, or damage cylinder.

  • Use a pressure regulator and a safety pressure relief valve as part of the pressure testing equipment. The safety pressure relief valve should be of the non-adjustable, non-tempering type. The valve should bypass any time the pressure exceeds its setting.

  • Open valve slowly; use regulators and safety valves that are in good working order.

  • The regulator should have two gauges; one to read tank pressure, the other to read line pressure. Properly maintained equipment will allow leak testing, purging, or dehydration to be done safely.

    Caution
  • Risk of Injury
  • Nitrogen (N2) is under 15,170 kPa, 151.70 bar, 2200 psig, or greater. Pressure is for full cylinder at 21 C (70 F). DO NOT use Oxygen (O2), acetylene, or any other types of pressurized gas on refrigeration systems or any component of a system.

Dehydration, pressure testing, purging, and soldering can be accomplished with the use of dry nitrogen (N2). The proper equipment and application of equipment is of greatest importance.

Purge High Side to Low Side

  1. Attach gauge manifold set (Refer to Gauge Manifold Set for proper procedure for connecting to compressor).

  2. Close both hand valves on the gauge manifold (front seated).

  3. Connect charging hose to a source of nitrogen. Adjust pressure regulator to the proper pressure for the required procedure.

  4. Purge system high side to low side.

Maximum Gas Pressures

The following procedures should utilize the following maximum gas pressure:

  • Leak Testing: 1034 to 1200 kPa, 10.34 to 12.00 bar, 150-174 psig.

  • Purging/Dehydration: 69 to 138 kPa, 0.69 to 1.38 bar, 10-20 psig.

  • Soldering: 35 kPa, 0.35 bar, 5 psig.

Evacuation Station and Unit Hook-up

1 Special, self-sealing quick disconnect couplers are required for R-404A/R-452A units 3 Iso Valve 5 To 220/190 Vac Power 7 Micron Meter
2 Gas Ballast Valve 4 Two-stage Vacuum Pump 6 Calibration Standard 8 Sensor