CSR-20 & CSR-40, September 1999
Refrigeration System Diagnosis and Service
Using Pressurized Nitrogen
6-9
2.
Attach gauge manifold set (refer to “Gauge Manifold Set
Attachment and Purging” for proper procedures).
3.
Attach refrigerant bottle charging hose to center of gauge
manifold and purge charging hose of air.
4.
Pressurize the system with refrigerant (GAS ONLY) until
345 kPa, 3.45 bar, 50 psig vapor pressure is achieved.
5.
Leak check the system with an electronic leak detector to
inspect all joints and connections. (Use soap solution as
an alternative test component.)
If no leaks are found but the system has lost its refrig-
erant charge, proceed to the next step.
6.
Close both hand valves on gauge manifold (front seated).
7.
Disconnect the refrigerant charging hose.
8.
Connect the charging hose to a source of nitrogen. Adjust
the pressure regulator to 1380 kPa, 13.80 bar, 200 psig.
See “Using Pressurized Nitrogen” in this chapter.
CAUTION: Nitrogen (N2 ) is under 15,170 kPa,
151.70 bar, 2200 psig pressure in a full cylinder
at 21 C (70 F). DO NOT use oxygen, acetylene or
any other type of pressurized gas in the system.
9.
Pressurize the system with nitrogen to 1380 kPa, 13.80
bar, 200 psig.
10. Close the supply valve on the nitrogen bottle.
11. Use an electronic leak tester to inspect all joints and con-
nections. (Use a soap solution as an alternative test com-
ponent.)
NOTE: If system leakage is indicated, loosen
supply line hose fittings to release pressure.
Repair leakage condition.
12. If system repair is necessary, recheck system after repairs
are completed.
Using Pressurized Nitrogen
The improper use of high pressure cylinders can cause physi-
cal damage to components, or personal injury, or cause stress
that would lead to failure of components.
Safety Precautions
Observe the proper handling of cylinders:
1.
Always keep protective cap on cylinder when not in use.
2.
Secure cylinder in proper storage area or fastened to cart.
3.
DO NOT expose to excessive heat or direct sun light.
4.
DO NOT drop, dent, or damage cylinder.
5.
Use a pressure regulator and a safety pressure relief valve
as part of the pressure testing equipment. The safety pres-
sure relief valve should be of the non-adjustable, non-tem-
pering type. The valve should bypass any time the pres-
sure exceeds its setting.
6.
Open valve slowly; use regulators and safety valves that
are in good working order.
7.
The regulator should have two gauges; one to read tank
pressure, the other to read line pressure. Properly main-
tained equipment will allow leak testing, purging, or dehy-
dration to be done safely.
Typical Pressurized Gas Bottle with Pressure
Regulator and Gauges
1. Line Pressure
2. Tank Pressure
3. Tank
4. Pressure Test Line to System
5. Safety Valve
6. Pressure Regulator
