What kind of equipment is suitable for high and low pressure refrigerant charging method
There are generally two types of refrigerant charging methods: low-pressure charging and high-pressure charging. The advantage of the low pressure charging method is that it is easier to control the amount of refrigerant charged, safe and not easy to damage the components, but the charging time is longer, and the refrigerant is in a gaseous state with a large water content, which must be processed by a dryer. The advantage of the high-pressure charging method is that the charging time is short, but it is difficult to control the refrigerant charge, especially for small equipment, so it is suitable for refrigeration equipment with a large refrigerant charge.
At present, small and medium air conditioners and other refrigeration equipment often use low-pressure gas refrigerant charging methods during maintenance.
①Put the refrigerant cylinder on the scale and screw on the cylinder connector.
②Tighten the compressor low-pressure suction control valve clockwise, close the multi-channel port, and then unscrew the screw plug and other connecting parts on the multi-channel port.
③Install a three-way reversing valve, one end is connected to a vacuum pressure gauge, the other end is connected to a copper pipe with a diameter of 6mm, and connected to the joint of the refrigerant cylinder through a filter drier.
④ Slightly open the valve on the cylinder to fill the copper pipe with Freon gas, then slightly open the joint nut on the three-way reversing valve joint, use the pressure of the Freon gas to exhaust the air in the filling pipe and the filter drier, and then Tighten all joint nuts and open the cylinder valve.
⑤ Make the connecting pipe and the filter drier in a state of being unstressed, read the cylinder weight from the scale, and pay attention to the filling equipment and the scale not to bear external force, so as not to affect the reading.
⑥ Rotate the low-pressure suction control valve of the compressor in a clockwise direction, so that the multi-purpose channel port is in communication with the low-pressure suction pipe and the compressor, and the refrigerant enters the refrigeration system. When charging, pay attention to the change of the weight of the refrigerant cylinder and the change of the pressure of the low pressure gauge (generally no more than 98 ~ 196kPa). If the pressure has reached equilibrium but the charging volume has not reached the specified value, the cooling water (or cooling fan) should be turned on first, and the compressor should be started for charging after the cooling water flows out of the condenser water outlet. Before starting the machine, turn the low-pressure suction control valve clockwise and close the multi-purpose channel port to avoid liquid shock (if liquid shock occurs, stop it immediately), and then slowly open the mostly-used channel port clockwise to make the refrigerant Enter the refrigeration system.
⑦When the specified filling volume is reached, first close the cylinder valve, then turn the low-pressure suction control valve counterclockwise, close the multi-purpose channel port, and stop the compressor immediately.
⑧ Remove the connecting nut, filling equipment and three-way reversing valve, install and tighten the fine-tooth joint, low-pressure meter and other components that were previously removed.
⑨ Turn the low-pressure suction valve clockwise 1/2 ~ 3/4 turn to make the multi-purpose channel port communicate with the low-pressure gauge and the pressure controller (the opening size is subject to the low-pressure gauge pointer without bounce).
