1. Pressure gauge

Refrigerant leakage is a common fault of the air conditioner. In order to detect whether the refrigeration dose in the system is sufficient, pressure gauges are commonly used. Pressure gauges are commonly used as detection tools in Freon refrigeration systems. Their shell diameters range from 60mm to 250mm. They have various specifications. The range of vacuum pressure gauges suitable for the air conditioner refrigeration system is -0.1MPa to 2.5MPa, as shown in Figure 2-33,

The pressure gauge is often used together with the three-way repair valve. Turning the three-way repair valve knob clockwise can reduce the valve hole. When turning the knob clockwise to the end, the corresponding piping and the outdoor unit air circuit will be cut off. When turning the knob counterclockwise, the valve hole will expand, and the corresponding piping and the outdoor group air circuit will be connected. The refrigeration system and the pressure gauge on the three-way repair valve are always connected, independent of the position of the knob, The refrigeration system can be vacuumized, filled with refrigerant and tested for pressure.

2. Tube expander

When two copper tubes are connected, one copper tube needs to be inserted into the other copper tube. At this time, it is often necessary to expand the inner diameter of the end of the inserted copper tube so that the other copper tube can be inserted in a consistent manner. Only in this way can the two copper tubes be firmly welded and not easy to leak. The role of the tube expander is to expand copper tubes of different specifications as required. When expanding the pipe, first put the annealed copper pipe into the corresponding hole diameter of the pipe clamp. The length of the copper pipe extending out of the pipe clamp varies with the pipe diameter. For the copper pipe with large pipe diameter, the expansion length should be larger, and for the copper pipe with small pipe diameter, the expansion length should be smaller Ф 8 copper tube, generally the tube expansion length is about 10mm. Tighten the nuts at both ends of the pipe clamp to firmly clamp the copper tube. Insert the tube expansion head with the required caliber, slowly rotate the screw of the tube expander clockwise until the required length is reached. The physical object of the tube expander is shown in Figure 2-34, and the structure is shown in Figure 2-35.

3. Flare

The flaring device is used to expand the bell mouth for the copper pipe, so as to connect the indoor and outdoor units of the split type air conditioner through piping. When flaring, first put the annealed copper pipe on the connecting nut, and then put the copper pipe into the corresponding hole diameter of the pipe clamp. The height of the copper pipe exposed from the clamp is one-fifth of the diameter of the copper pipe. Tighten the nuts at both ends of the pipe clamp, press the conical head of the flaring top compressor on the pipe mouth, and slowly rotate the screw clockwise, Extrude the nozzle into a bell mouth, as shown in Fig. 2-35:

4. Pipe cutter

When repairing and installing the air conditioner, it is often necessary to use a pipe cutter to cut copper pipes of different lengths and diameters. The pipe cutter has different specifications, and the structure is shown in Figure 2-36:

When cutting the copper tube, place the copper tube between the two rollers of the pipe cutter, turn the feed button clockwise to clamp the copper tube between the cutter and the roller, and then rotate the feed button while rotating the cutter knife around the copper tube. When rotating the feed button, the force must be uniform and soft, otherwise the copper tube may be extruded and deformed. After the copper tube is cut off, use a cutter to remove the burrs on the edge of the tube mouth to prevent copper chips from entering the refrigeration system.

5. Pipe bender

The pipe bender is a tool used to change the shape of the copper pipe and process the copper pipe into the desired shape. The pipe bender has various sizes and specifications, and is suitable for bending copper pipes with a radius of less than 20mm. When bending, put the annealed copper pipe into the wheel groove of the pipe bender, lock the pipe clamp hook, and slowly rotate the handle until the required angle is reached, as shown in Figure 2-37:

6. Gas welding equipment

The refrigeration system of the air conditioner mostly uses copper pipes, and gas welding is required during maintenance. The traditional gas welding equipment uses oxygen and acetylene gas to mix and produce high temperature flame after ignition. Now more liquefied petroleum gas is used, and oxygen combustion supporting liquefied gas welding machine is used to weld the pipeline of the refrigeration system. The gas welding equipment is mainly composed of three parts: gas cylinder, connecting hose and welding gun.

7. Clamp meter

Clamp on meter is a widely used measuring instrument, which is the most commonly used tool for electrical troubleshooting of refrigeration equipment. It can measure AC or DC voltage, AC current, resistance, etc. The physical objects are shown in Figure 2-38:

① Measure AC and DC voltage

First, switch the change-over switch to AC voltage (ACV) or DC voltage (DCV), select a range greater than the measured voltage, and then insert the red and black probes into the sockets of the power supply sockets to be measured. The panel displays the value of the measured voltage. The AC voltage has no fixed polarity, so the probes of the clamp meter can be used regardless of the positive and negative poles. When measuring the DC voltage, turn the change-over switch to the DC voltage range (DCV), and pay attention to selecting a range larger than the measured voltage. At the same time, make sure the polarity of the measured voltage. When measuring, the red probe is connected to the voltage positive pole, and the black probe is connected to the voltage negative pole. If the polarity of the probe is connected incorrectly, the clamp meter may be damaged.

② Measuring AC current

Turn the change-over switch to the appropriate range of AC current (ACA). When measuring, as long as the measured wire is clamped in its clamp mouth, the display screen can indicate the current intensity in the wire using the electromagnetic induction principle.

③ Measuring resistance

Rotate the change-over switch to the appropriate range. Before measurement, connect the two probes directly (short circuit). At this time, the display screen should read 0 Ω and emit a beep. If the displayed number is not 0 Ω, it means that the clamp meter is damaged or the power is insufficient. When measuring, connect the probe to both ends of the measured resistance, and the number displayed on the screen is the measured resistance value.