After the air conditioning system is vacuumed, why does the pressure decrease during the pressure ho

Do you mean that the pressure decrease is that the gauge hand is shifting in the direction of 0, it should be said that the pressure is rising, right? The reason may be that when the gas in the container is pumped out to negative pressure, the temperature of the container will decrease, and the surface of the container will absorb heat during the period of maintaining pressure, and the gas in the container will expand, and the watch hand will shift to the 0 direction.

The common way to test whether the air conditioning duct is leaking is to add a certain pressure of nitrogen, and then close the system to observe whether the pressure of the pressure gauge remains unchanged, if it is significantly reduced within a few hours, it means that the system has a leak, and the leakage point needs to be checked.

Vacuum pressure holding is another inspection method, not pressurization but evacuation method, so that the pipeline system is in a negative pressure state, to observe whether the reading of the vacuum gauge has been constant, if the reading increases, it indicates that there is a leak in the system. The advantage of vacuum pressure holding is that it is not affected by temperature (after pressurizing with gas, the thermal expansion and contraction caused by temperature changes will make the pressure gauge reading unstable and easy to misjudge), but the maximum vacuum can only be minus one atmosphere, and it is impossible to accurately judge small leaks or leaks that only occur under high pressure. The most accurate method is to put it in water after pressurization to see the bubbles, which is intuitive and accurate.

However, this method also has limitations, it can only detect the internal or external unit alone, and cannot detect whether there is leakage in the connecting pipe and online joint.

After the system is vacuumed, the pressure is maintained for at least 20 minutes, and the pressure does not change significantly, and the refrigerant can be added.

How long does it take for an air conditioning system to vacuum and maintain pressure?

The vacuum pumping time of the air conditioner, the size of the vacuum pump, the size of the air conditioning system, the cleanliness and dryness of the inside of the pipeline are broken.

If it is a new and clean system, if you use a 4-liter pump for a 1P air conditioner, you can achieve the vacuum requirement in 2 minutes. If the air conditioning system is originally filled with refrigerant, the initial manuscript code should be maintained for more than 15 to 30 minutes.

How to maintain pressure after vacuum extraction of air conditioner?

When the air conditioner is vacuumed, the high and low pressure valves can not be opened, and the connecting hose is connected to the fluorine nozzle of the machine, depending on the size of the machine, the pumping time also needs to be extended, generally 15 minutes for hanging, 25 minutes for the cabinet machine.

After vacuuming, hold the pressure for 3 5 minutes to see if the pressure rebounds, if there is rebound (check whether the connecting pipe joints, connecting copper pipes and other parts are tightened until there is no leakage, and then vacuum again).

Press first close the valve on the vacuum gauge, then close the vacuum pump, open the high-pressure valve, see the pressure rise, close the high-pressure valve, (this sequence is to detect whether the hose thimble connected to the fluorine nozzle has been jacked out of the ejector in the fluorine nozzle, if the pressure on the table does not rise, the thimble does not work, and the vacuum must be pumped again.)

Ensure that the air enters the system again because of the negative pressure in the pipe when connecting the hose), quickly remove the connecting hose, tighten the fluorine nozzle cap, after the above steps are completed, open the high and low pressure valves, tighten the high and low pressure valve covers, and test the machine.

Summary. The production process of air conditioning is that after the vacuum is pumped, the high and low pressure globe valves are locked to the valve core, and the refrigerant is filled from the process pipe, and after the filling is completed, the process pipe is welded with a welding torch to the tail of the process pipe to seal it. The purpose of this is to make the system of the outdoor unit appear as a vacuum sealing system, and then add refrigerant to seal the outdoor unit.

The production process of air conditioning is that after the vacuum is pumped in the imitation shed, the spool of the high and low pressure hall stop valves are locked, and the refrigerant is filled from the process pipe, and after the filling is completed, the process pipe is welded with a welding torch to the tail of the process pipe and sealed. The purpose of this is to make the system of the outdoor unit present a vacuum sealing system, and then add a refrigerant cover to make the refrigerant sealed in the outdoor unit.

Six steps of vacuuming:1First, confiscate the hexagon wrench of the installer.

2.Connect the pipes connecting the inner and outer machines and tighten them. 3.

Connect the pressure gauge to connect the vacuum pump at the repair port of the trachea (thick pipe) three-way valve, open the vacuum pump first, then open the pressure gauge valve, and then pump the pressure negative after the vacuum starts, and then pump for 15-20 minutes, subject to the negative pressure value of the pressure gauge. 4.Close the pressure gauge valve first, then turn off the vacuum pump.

Look at the pressure gauge and see if the pressure rises. 5.Return the hexagon wrench to open the liquid pipe valve (thin pipe two-way valve 1 4 turns), close it after about 10 seconds, and use a leak detector or soapy water to detect the position of the connector.

6.Extract the table, the liquid pipe and the trachea valve are all opened, and the first step of vacuuming the debugging machine is opened: 1

First confiscate the inner six wrenches of the accompanying installation workers. Unless you trust, he will not use a hex wrench until you agree, in order to prevent any unnecessary operation by the installer.

How can the high and low pressure valves be closed tightly and still vacuumed.

It is not connected to the vacuum pump, how can you pump the vacuum in the air conditioner?

Dear, you look for after-sales to see if you can solve it.

Summary. The specified time for air conditioner vacuum and pressure retention is determined according to the actual situation. In general, air conditioning pumps need to be vacuumed for 20 to 30 minutes to ensure that the air and moisture in the system are adequately removed.

Subsequently, a holding pressure test is usually performed for 20 to 30 minutes to check the system for leaks. If the system is normal and leak-free, and the air pressure is stable during evacuation and packing, then this step can be completed. However, in order to ensure quality, it is advisable to follow the specific requirements of the equipment manufacturer and refer to the relevant technical standards or guidelines to perform air conditioner evacuation and pressure holding operations.

This ensures that the system is functioning properly and provides efficient heating and cooling.

Fellow, I really didn't understand, I can be more specific.

The specified time for air conditioner vacuum and pressure retention is determined according to the actual situation. Generally speaking, air conditioning pumps need to be evacuated for 20 to 30 minutes to ensure that the air and moisture in the system are fully removed. Subsequently, it is necessary to keep a pressure test on Luxiao, which usually takes 20 to 30 minutes to check whether there is a leak in the system.

If the system is normal and leak-free, and the air pressure is stable during evacuation and packing, then this step can be completed. However, in order to ensure quality, it is advisable to follow the specific requirements of the manufacturer of the equipment and refer to the relevant technical standards or guidelines to perform air conditioning evacuation and pressure holding operations. This ensures that the system is functioning properly and provides efficient heating and cooling.

First, the principle of vacuuming:

1) After the vacuum pump is started, the non-condensable gas and water vapor in the system are pumped out first, and then only water molecules (liquid state) remain.

2) With the increase of vacuum, the absolute pressure in the system decreases, when the absolute pressure in the system decreases to the saturated water vapor pressure corresponding to the ambient temperature, the remaining water molecules in the system boil into water vapor, which is continuously pumped out;

3) It should be noted that during the vacuum extraction process, under normal operating conditions, the temperature in the system is consistent with the temperature of the external environment. This is also the reason why the lower the ambient temperature, the more difficult and slower it is to evacuate.

Second, why the inverter air conditioner must be vacuumed.

Inverter air conditioners generally use R410A refrigerant or R32 refrigerant. R32 must not be mixed with air, must be vacuumed, to avoid accidents, and R410A inverter air conditioner to vacuum, mainly for the following two reasons:

1) R410A is a near-azeotropic refrigerant, which is a mixture of two refrigerants (R32 and R125 (50%:50%WT)) according to 1:1, and the proportion will change when it is in the gaseous state.

The reason is simple, because the boiling points of the two are different, one has been vaporized and the other has not. Therefore, the external air evacuation method cannot be used, because the external air evacuation method will change the refrigerant ratio.

2) R410A compressor is lubricated with ether oil. Ether oil has a strong absorption of water vapor, and then becomes an acidic substance, and the presence of acidic substances in the refrigeration system can be imagined. The mineral oil lubricant used in the R22 system is insoluble to water and does not produce other substances.

3) Therefore, the R410A system must be vacuumed and installed. The R22 system does not have the above problems at all, but from the perspective of air conditioning performance, it should be vacuumed during installation, because the air exhaust method cannot remove the air in the system after all, and it belongs to an extensive operation.

3. The hazards of not vacuuming:

1) The interaction between lubricating oil and moisture will form acid, which has a corrosive effect on copper pipes, and then affects the service life of air conditioners.

2) After the copper is corroded, the copper ions are free in the refrigerant, and will be replaced by iron when passing through the compressor, resulting in the phenomenon of "copper plating" and damaging the compressor.

3) The mixing of water in the refrigerant will cause ice in the valve port or capillary of the expansion valve, and there will be "ice blockage", resulting in the failure of the air conditioner.

4) It will increase the condensation pressure of the system, the discharge temperature of the compressor, and the power consumption.

Air conditioning is three points quality, seven points installation.

Vacuum pumping is an indispensable process in the installation process of fluorine-free inverter air conditioner in jujube stool, and it is also the most critical step to ensure the high performance of air conditioner.

However, the professionalism of the installer team is uneven, and there is no guarantee that everyone will consciously operate this process.

The normal vacuum pumping time must be 15-20 minutes to ensure that the closed air in the system is completely pumped out, otherwise it is easy to affect the overall performance of the air conditioner, resulting in poor cooling and heating effect and high energy consumption.

In the vacuum pipeline, add refrigerant, there will be refrigerant pressure in the pipe, so the pressure gauge will rise to show the pressure value.

The pressure value can be seen from the pressure to see the amount of refrigerant.

If the air conditioner is running with R410A refrigerant, the low pressure is about the same;

The high pressure is about the same.

If the air conditioner is running with R22 refrigerant, the low pressure is about the same;

The high pressure is about the same.

1mpa=。

Unqualified vacuum extraction of the air conditioning and refrigeration system will lead to an increase in the pressure of the refrigeration system during operation, rather than a decrease in the operating pressure of the system.

Unqualified evacuation also indicates that the amount of non-condensable gas air in the system pipeline is excessive, which will directly lead to the increase of the refrigerant pressure in the operation of the air conditioning system, and the refrigeration effect of the air conditioning will be seriously deteriorated.