First, multiple online refrigerant recovery method

The multi-line system needs to be filled with a large amount of refrigerant. When it is necessary to repair the outdoor unit or the indoor side, a certain amount of refrigerant can be recovered from the cost consideration. Theoretically, the refrigerant can be recycled to the outdoor unit or indoor side, or to any outdoor unit and indoor side. The following methods are for reference.

1. Recycle the refrigerant to three outdoor units: short-circuit the low-voltage switch of three outdoor units, connect the pressure gauge to the A0 stop valve; use forced cooling operation, turn off B0, B1, B2 after running for a period of time, when the pressure gauge The pressure drops to zero, and A0, A1, and A2 are turned off (three people need to operate at the same time).

2. Recycle the refrigerant to the indoor side: short-circuit the low-voltage switches of the three outdoor units, connect ST1 of each outdoor unit to SV1, connect the pressure gauge to D0; press the forced cooling button, turn off B0 after power on, B1, B2 run for a period of time, when the pressure of the pressure gauge drops to zero, close A0, A1, A2 (three people need to operate at the same time).

3. Recycle the refrigerant to the main unit and the indoor side: short-circuit the low-voltage switch of slave 1 and slave 2, close C0 and D0, connect ST1 of each outdoor unit to SV1, and connect the pressure gauge to D1; press Force the cooling button, turn off B1 and B2 for a period of time after power on. When the pressure of the pressure gauge drops to zero, close A1 and A2 (two people need to operate at the same time)

4. Recycle the refrigerant to the slave and indoor side: short-circuit the low-voltage switch of the host, turn off C1, C2, D1, D2, connect ST1 of each outdoor unit to SV1, connect the pressure gauge to D0; press force Cooling button, turn off B0 for a period of time after power on, when the pressure of the gauge drops to zero, turn off A0.

Second, add refrigeration oil to the running outdoor unit

Add refrigeration oil to the system at the project site (such as D3 system). The general practice is: firstly recycle the system refrigerant to the outdoor unit, then vacuum the system, then use the vacuum to pump the frozen oil into the system, and then vacuum it. The refrigerant starts running. If you want to add frozen oil to the running outdoor unit, you can try the following small tooling, which can be used in both the laboratory and the engineering site.

1. Make small tooling as shown in the figure. The tank body can be used with low pressure tanks, small refrigerant tanks, etc.; the shut-off valve can be used with Ф16 or Ф19 caliber; the tank body is connected with a table joint;

2. Open the shut-off valve A and pour the frozen oil from it.

3. Connect the watch joint B to the refrigerant tank, open the shut-off valve A, and use the refrigerant to discharge the air above the tank; then close the shut-off valve A; as shown in Figure 2.

4. Connect the watch connector B to the refrigerant tank, and the watch connector C is connected to the low pressure ball valve of the outdoor unit; to make the outdoor unit cool and operate, the pressure of the refrigerant in the refrigerant tank can push the frozen oil to the running outdoor machine side pipe. .

Note: The vacuum in the tank must be ensured, and the vacuum can be taken from the joint B of the filler after the refueling tool (Fig. 2).

Third, quickly check the communication line of the system

During the commissioning of multi-line systems, it is most prone to communication failures, incorrect internal machines, or mismatched communication systems of multiple systems; some of the personal on-site processing experience is summarized as follows:

1. Under the premise of ensuring that the outdoor electrical control is normal and each indoor unit is energized, the low-voltage switch of one outdoor system is pulled out (or other protection device), and the alarm light (red light) flashes indoor slowly. The machine is connected to the same communication line.

2. Power on all indoor units, and only power up one outdoor system. At this time, the indoor unit that is running slowly (indicating normal) is communicating with the outdoor system; Whether the pipeline system and the communication system are in one-to-one correspondence.

3. For the same indoor unit system, the resistance between P and Q of the innermost machine can be measured; if the resistance is very close to zero, there must be a short circuit between P and Q somewhere. Under the premise of power failure, connect the P and Q of the innermost machine, and then measure the P and Q resistance of the innermost machine. If it is infinity, there is some open circuit.

4. Press and hold the check button on the remote control receiver of the internal machine (press the address code of the internal machine for 5 seconds to display the capability code for 10 seconds), and check each address code.

For example, after 5 seconds of continuous pressing, the “Run” light and the “Alarm” light are always on, indicating that the address code is (8+1)=9; (Note: If the indicator light is always on, press the above calculation; if indicated If the light is shining, add 16 to the original calculation code; for example, after 5 seconds of continuous operation, the “Run” light and “Alarm” flash, indicating that the address code is 16+(8+1)=25.)

Fourth, the cable current carrying capacity estimation method

The current carrying capacity of the wire is related to the wire cross section. It is also related to the material, type, laying method and ambient temperature of the wire. There are many factors affecting and the calculation is complicated. The current carrying capacity of various conductors can be found in the manual; however, if it is at the engineering site, it can be calculated directly by using the mouth and some simple mental arithmetic.

Estimated vocabulary:

Multiply by 9.5 and multiply by nine, go up and subtract one by one; thirty-five by three-five, double-group reduction by five; conditions have changed and converted, high-temperature nine-fold copper upgrade; the number of tubes is two or three , eighty-seven percent off full load.

Description:

1. The current carrying capacity (safety current) of various insulated wires (rubber and plastic insulated wire) is not directly indicated, but is expressed by “multiplied by a certain multiple”. It can be seen from the above table that the multiple decreases as the cross section increases.

2. “Two to five times multiplied by nine, and one step is reduced by one.” It is said that the aluminum core insulated wires of various sections of 2.5 mm' and below have a current carrying capacity of about 9 times the number of sections. For example, a 2.5 mm' wire has a current carrying capacity of 2.5 x 9 = 22.5 (A). The multiple of the current carrying capacity and the number of sections from the wires of 4 mm' and above is lined up along the line number, and the multiples are successively decremented by 1, that is, 4 × 8, 6 × 7, 10 × 6, 16 × 5, 25 × 4.

3. “Thirty-five times and three-five-five, double-group reduction of five points”, said that the current carrying capacity of the 35mm’ wire is 3.5 times the number of sections, that is, 35×3.5=122.5(A). From a wire of 50 mm' or more, the multiple relationship between the current carrying capacity and the number of sections becomes a set of two line numbers, and the multiple is sequentially decreased by 0.5. That is, the current carrying capacity of the 50, 70 mm' wire is three times the number of sections; the 95, 120 mm" wire current carrying capacity is 2.5 times the cross-sectional area, and so on.

4, "Conditions have been changed and converted, high temperature nine fold copper upgrade." The above-mentioned mouth is determined according to the condition that the aluminum core insulated wire and the bright coating are at an ambient temperature of 25 ° C. If the aluminum core insulated wire is applied in an area where the ambient temperature is higher than 25 °C for a long time, the current carrying capacity of the wire can be calculated according to the above-mentioned calculation method of the mouth and then 10% off; when the copper wire is insulated, the copper core is used. Its current carrying capacity is slightly larger than that of the same specification aluminum wire. The above-mentioned port method can be used to calculate the current carrying capacity of one wire number than the aluminum wire. For example, the current carrying capacity of a 16 mm' copper wire can be calculated as a 25 mm' aluminum wire.

5, "wearing pipe, temperature, eight or nine folds" means: if the pipe is laid (including the laying of the trough plate, that is, the wire is covered with a protective cover layer, it is not clear), after the calculation, another 20% off; If the temperature exceeds 25 °C, the calculation will be followed by a 10% discount. If the temperature is over 25 °C, it will be 10% off after hitting a 20% discount, or a simple 30% discount. For example, the calculation of the download flow rate of the aluminum core insulated wire under different conditions: when the cross section is 10 mm', the current carrying capacity is 10×5×0.8═40 amp; if it is high temperature, the current carrying capacity is 10×5×0.9═ 45 amp; if the tube is hot and high, the current carrying capacity is 10 × 5 × 0.7 ═ 35 amps.