Adding method of refrigerant in central air conditioner

Adding method of refrigerant in central air conditioner

How to add refrigerant to the central air conditioner, what operating methods do you know? Let’s take a look with the editor today!

　　1, quantitative fluoride

Connect the three-way valve, pressure gauge, fluorine hose, fluorine bottle or vacuum pump to the process port of the three-way stop valve. After fluorine is discharged and vacuumed, start to add fluorine slowly. Use a platform scale and other more accurate measuring tools to weigh, When the reduction of fluorine in the fluorine bottle is the standard fluorine addition on the air conditioner nameplate, close the fluorine bottle valve.

　　2, measure current

Set the air conditioner in the cooling or heating high-speed wind state (the inverter air conditioner is set in the test operation state), and observe the change of the clamp ammeter while adding fluorine at the process port of the low-pressure shut-off valve. When it is close to the rated working current calibrated on the air conditioner nameplate When the value is set, the fluorine cylinder valve is closed. At this time, let the air conditioner continue to operate for a period of time. When the room temperature is close to 27°C in the cooling state or the room temperature is close to 20°C in the heating state, the outdoor unit air temperature and the grid voltage are considered to affect the rating. Factors of working current, while fine-tuning the amount of fluorine added to reach the rated working current value to achieve correct fluorine addition. The reason for the fine-tuning is that the rated working current value calibrated on the air conditioner nameplate is tested by the air conditioner manufacturer under the following conditions Data: Cooling status, fan high-speed wind at power supply voltage 220V or 380V, indoor air temperature 27℃, outdoor unit air temperature 35℃; heating status, fan high speed wind at power supply voltage 220V or 380V, indoor air temperature 20℃, outdoor unit The air temperature is 7°C. The fine-tuning data summarized in practice is: in the cooling state, the outdoor unit air temperature is 35°C as the scale, and the outdoor temperature increases or decreases by 1°C, and the rated operating current value is increased or decreased by 1.4%; heating state When the outdoor unit air temperature is 7℃ as the scale, the outdoor temperature increases or decreases by 1℃, increase or decrease 1% of the rated operating current value; in the cooling or heating state, the rated power supply voltage is 220V or 380V as the scale, Every time the power supply voltage increases or decreases by 1V, the rated operating current value is reduced or increased.

　　3, pressure measurement method

Put the air conditioner in a high-speed cooling state (in winter, when heating needs to add fluoride, set the air conditioner in a forced cooling state or place the room temperature sensor in warm water at about 27°C to simulate the summer temperature to keep the air conditioner in a cooling state), At the process port of the low-pressure shut-off valve, observe the low pressure of the vacuum pressure gauge while adding fluorine. When the low pressure is 0.49MPa (in summer) or 0.25MPa (in winter), close the fluorine cylinder valve. Then consider the outdoor unit air temperature and indoor cooling load The size and other factors that affect the low pressure pressure, fine-tune the amount of freon and the gauge pressure, so as to correctly add fluorine. The reason for the fine-tuning is that the low pressure is proportional to the indoor cooling load, that is, the greater the cooling load, the higher the pressure, and vice versa. ;Because the fluorination process port and surrounding pipes are installed outdoors, their pressure and evaporation temperature are greatly affected by the outside air temperature. The actual pressure and evaporation temperature of the indoor heat exchanger should be higher in summer and lower in winter. Summary in practice When the fan has high-speed wind and the indoor temperature is 27°C, the low-pressure pressure data is shown in the attached table.

　　 4. Observation method

Set the air conditioner to operate under high-speed air condition for cooling or heating. When the amount of fluorine is correct, the temperature difference between the inlet and outlet of the indoor heat exchanger is 10cm: greater than 12°C during cooling, greater than 16°C during heating; indoors during cooling All the heat exchangers are condensed, the evaporation sound is averagely low, the outdoor shut-off valve is condensed, the condensation drips continuously in summer, the indoor heat exchanger and the capillary tube are free of frost or dew, etc.; when heating, the indoor heat exchanger wall temperature Above 40°C.

In actual maintenance, when the frequency conversion air conditioner has a high requirement for the correctness of the amount of fluorine, or the fixed frequency air conditioner needs to be vacuumed due to the refrigeration pipeline system, the quantitative fluoride method should be adopted. If the pipeline system needs to be supplemented with fluorine, it is appropriate Adopt the method of measuring current as the main, measuring gauge pressure as the supplement, and taking into account the observation.