How to vacuum when installing a split air energy heat pump?

How to properly vacuum when installing air energy.

Six steps to vacuum:

1. Tool preparation: prepare tools such as hexagonal wrench, vacuum pump, pressure gauge, etc.

2. Connect the pipes connecting the internal and external units and tighten them.

3. Connect the pressure gauge to the repair port of the three-way valve of the air pipe (thick pipe) and connect it to the vacuum pump. First, open the vacuum pump and then open the pressure gauge valve. After vacuuming starts, set the pressure to negative 0.1MPA, and then pump for 15-20 minutes, based on the negative pressure value of the pressure gauge.

4. Close the pressure gauge valve first, then close the vacuum pump. Look at the pressure gauge to see if the pressure rises.

5. Use a hexagonal wrench to open the liquid pipe valve (1/4 turn of the thin pipe two-way valve), close it after about 10 seconds, and use a leak detection gun or soapy water to detect the position of the connector.

6. Remove the meter, open all the liquid pipe/air pipe valves, and start the air energy test machine.

Step 1: Prepare tools such as hexagonal wrench, vacuum pump, pressure gauge, etc.

Step 2: Connect the pipes connecting the internal and external units and tighten them.

The interface of the thin pipe is a two-way valve, and the interface of the thick pipe is a three-way valve. Start to unscrew the small plug cap of the thick pipe interface.

Step 3: Connect the pressure gauge to the repair port of the three-way valve of the air pipe (thick pipe) and connect it to the vacuum pump. Turn on the vacuum pump first and then open the pressure gauge valve. After the vacuum pumping starts, set the pressure to negative 0.1MPA, and then pump for 15-20 minutes, based on the negative pressure value of the pressure gauge.

First, look at the value of the pressure gauge before the gauge is connected. The double-head gauge is like this (blue on the left, red on the right)
Connect the middle interface of the pressure gauge to the vacuum pump with a blue tube, and connect the repair port of the three-way valve of the air pipe (thick pipe) of the external unit to the right side of the pressure gauge with a red tube, and check whether each connection is tight.
  Purpose:
  a, remove the air in the connecting pipe and indoor unit;
  b, the boiling point of water is reduced under a vacuum state. To reduce costs, most manufacturers in my country no longer use inert gas protection for indoor units and connecting pipes. Air containing water will enter oxidation and other impurities may absorb water.
  c, pressure only ensures that the air is roughly discharged, and sufficient time is the guarantee for the complete removal of moisture.
All connections are completed.
It is recommended to open the pressure gauge valve after opening the vacuum pump and start vacuuming. At this time, check the value of the pressure gauge.
Vacuuming officially begins.
It is recommended to set the pressure to negative 0.1MPA, and then pump for 15-30 minutes (different horsepower time is different), based on the negative pressure value of the pressure gauge.
Step 4: First close the pressure gauge valve, then close the vacuum pump, check the pressure gauge, and observe whether the pressure rises.
  Purpose:

  a, prevent the lubricating oil in the vacuum pump from entering the system under negative pressure. Different types of lubricating oil will cause damage to the system, especially the R410A system. All conditions should use a vacuum pump with a toe return device to prevent air backflow;

  b, maintain pressure and detect leaks (negative pressure leak detection means, just observing whether the pressure rises, positive pressure leak detection can also be used).

Step 5: Use an inner hexagonal wrench to open the liquid pipe valve (1/4 turn of the thin tube two-way valve), close it after about 10 seconds, and use a leak detection gun or soapy water to detect the connector and other positions.

   Purpose:

  a Make the pipeline into positive pressure, which can be used for leak detection;

  b, remove the meter under positive pressure in the last step to prevent air backflow, otherwise the air backflow will make the previous steps in vain.

  Use a leak detection gun or soapy water to detect the connector and other positions, add water to produce foam and apply it to the interface of the pipeline to check whether there is any leakage.

Step 6: Remove the meter, open all the valves of the liquid pipe gas/pipe, and turn on the air to test the machine.