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Use flushing products according to the manufacturer’s instructions
To flush a system, use only dry nitrogen.
When pressure testing for leaks, use only regulated dry nitrogen or dry nitrogen plus trace amounts
of serial label refrigerant.
When purging or pressure testing any refrigeration or air conditioning system for leaks, never use
air, oxygen or acetylene. Oxygen can explode on contact with oil.
Acetylene can decompose and explode when exposed to pressures greater than
approximately 15 psig.
Combining an oxidizing gas, such as oxygen or air, with an HCFC or HFC refrigerant under
pressure can result in a fire or explosion. Use a pressure regulating valve and pressure gauges.
Commercial Cylinders of nitrogen contain pressures in excess of 2000 psig at 70°F. At pressures
much lower than 2000 psig, compressors can explode and cause serious injury or death. To avoid
over pressurizing the system, always use a pressure-regulating valve on the nitrogen cylinder
discharge. The pressure regulator must be able to reduce the pressure down to 1 to 2 psig and
maintain this pressure.
The regulating valve must be equipped with two pressure gauges:
One gauge to measure cylinder pressure
One gauge to measure discharge or downstream pressure
Use a pressure relief valve. (Not in the scope of manufacturer)
In addition to pressure regulating valve and gauges, always install a pressure relief valve. This can
also be frangible disc type pressure relief device. This device should have a discharge port at least
½” NPT size. The valve or frangible disc device must be set to 175 psig.
CAUTION
Do not pressurize the system beyond 150 psig field leak test pressure.
Disconnect nitrogen cylinder and release the pressure in the system before evacuating and
connecting a refrigerant container.
Nitrogen pressurizing method can be used for gross leak detection.
A more detailed leak check with refrigerant leak detectors is necessary.
Use only the refrigerant noted on the serial label of the unit.
