1. The valves and equipment within the system are in their proper state, including the suction and exhaust valves of the compressor, the inlet and outlet valves of the oil separator, and the inlet and outlet valves of the condenser and accumulator, all of which are in the correct open positions; The throttle valve opening is appropriate; All fans and motors operate smoothly; The water pump of the water circulation system is running normally without any abnormal noise; There is no serious water leakage in the water circulation pipeline and its connections. In the cold storage with cooling pipes or cold air fans, the pipes or cold air fan coils are uniformly covered with “dry frost”; The joints of the Freon refrigeration system should never leak oil (oil leakage indicates refrigerant leakage), and there should be no obvious ammonia leakage at the valves and connections of the ammonia system.
2. The condensing pressure and condensing temperature, as well as the evaporating pressure and evaporating temperature, have a corresponding relationship. The evaporating temperature and pressure are determined by the required refrigeration temperature, and during operation, the evaporating pressure and the suction pressure of the compressor should be approximately the same. The condensation temperature and pressure are determined by the temperature and flow of the cooling medium. In general, for national standard series refrigeration compressors, the maximum condensing pressure of R22 and R717 shall not exceed 1.8 MPa (gauge pressure). During operation, the condensing pressure is close to the discharge pressure of the compressor and the pressure of the accumulator. If they are not close, it is not normal.
3. The water pressure of the cooling water for the horizontal shell and tube condenser should exceed 0.12MPa, and a certain inlet temperature and water volume must be ensured; Therefore, air-cooled condensers should maintain a certain inlet air temperature, air volume, and wind speed on the windward side. When touching the outer shell of a horizontal shell and tube condenser with your hand, you should feel that the upper part is hot and the lower part is cool. The inlet and outlet water temperature difference of a vertical condenser is approximately within the range of 2-4 ℃, while that of a horizontal condenser is approximately 4-6 ℃.
4. The liquid level of refrigerant in the accumulator meets the requirements. During normal operation, the liquid level of the reservoir should be at 1/3 to 2/3 of the liquid level indicator.
5. The manual oil return pipe of the oil separator using manual oil return should be hot and cold at different times, with a typical hot and cold cycle of about 1 hour. The filter and solenoid valve coil above the liquid pipeline of the refrigeration system should operate at a warm temperature, and there should be no significant temperature difference between the left and right sides. Frosting and condensation should not occur, otherwise it will be blocked.
6. The frost or condensation on the throttle valve body should be uniform, and there should be no thick frost at the inlet. When the refrigerant liquid passes through the throttle valve, only a dull and small sound can be heard.
7. The protective devices on the equipment, such as safety valves, bypass valves, etc., should be flexible in opening and closing. Therefore, the setting values of various control devices, such as pressure controllers, differential pressure controllers, temperature controllers, etc., should be correct and operate normally. The pressure gauge pointer should be quite stable and flexible. The thermometer indicates correctly.