Leak testing
Before trying to locate leaks, increase pressure in all parts of the system. The use of carbon dioxide, nitrogen dioxide or dry through the system and a small amount of refrigerant (R-12, R-22, and others). Two methods can be used:
- Using an inert gas.
- Using refrigerant under pressure.
In the case of low pressure refrigerant is used, some other gas can be used for testing. This is also true if local code provides for the test pressure is higher than the pressure of the refrigerant vapor. Carbon dioxide, nitrogen or argon are in a satisfactory condition. However, the pressure can be dangerous. Attention: Never use oxygen, air, or any flammable gas for this purpose. An explosion may occur.
This testing must include in the liquid line, suction line, and all other parts installed. The only exception is a new condensing unit. He was tested at the factory. Installation of a pressure gauge. (Connection of the sensor can be destroyed as a result of pressure.) To increase pressure up to 30 pounds per square inch (100 psi (45 psi 115 psia or 311 kPa to 794 kPa).
Then close the cylinder valve.
If the gauge indicates the pressure drop across the hour, and raise the pressure test. It should be increased to 170 pounds per square inch (185 psia or 1277 kPa). Then test the system again. Do not exceed the pressure prescribed by the code. Too high a pressure can cause tearing of some part of the system. If the pressure does not demonstrate a reduction after 24 hours, the system is safe in operation. Purge the sample gas from the system. Evacuate in a deep vacuum, two - or three-stage vacuum and charge system. The device should be ready to work.
Leak testing using the refrigerant system is the most common noncode practice. This is convenient, no need for inert gas cylinder. In addition, leak testers should be a standard part of your tool kit.To do this, follow these steps. Install the pressure sensor in the system. Valve liquid line should be open enough to build 15 psig up to 30 psig inch (30 psia 45 psi 207 kPa 311 kPa) pressure throughout the system. Leak testing using one or more of the following:
- Lather.
- Halide torch.
- Electronic leak detector.
- Liquid tracer.
- Ultraviolet fluorescent leak detectors. (They are used on large systems refrigerant leak detection.)
If no leaks are detected at low pressure, increase system to full refrigerant pressure (the vapor pressure) and test again.
If the leak is found, the system is restored to atmospheric pressure. Open system for a leak points and inspect all parts. Replace any defective parts, clean and assemble. If soldered or brazed joint flows the flow of heat, and take it completely apart. Clean and assemble, then repeat leak detection procedures. If no leaks are found in this part of the instrument is ready for operation.
When blowdown piping and pressure test with nitrogen or carbon dioxide, use the exact pressure regulator. Use the safety valve designed opening of 180 psi (1346 kPa). Pressure shall not exceed 170 pounds per square inch (185 psia or 1277 kPa) when testing with C02 or nitrogen. Cm. Chapter 12 for the safe use of high pressure gases. Some of the motor-compressor of the domes are designed to operate at low pressure. Be sure to read the information about the products, to find the maximum safe pressure...
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Industrial