Vacuuming • Removing air from the air conditioning line

When connecting the copper tubes of the air conditioner, through which the refrigerant circulates, to the units of the split system, their complete drainage is an inevitable action. The fact is that during the assembly and installation of the route, air and moisture enter the tubes, which adversely affect the performance of the system and the state of the freon. Therefore, before starting the refrigerant, a vacuum must be created inside the route, pumping out excess gases, and completely sealing it. This is done using two tools:

• vacuum pump, which is connected directly to the valves of the outdoor unit after installing the tubes and connecting them to the units;
• gauge manifold showing the level of pressure in the system.

It is this important work and its nuances that this article is devoted to — how, in what order and why to install a vacuum in the air conditioner piping system.

Trunk connection

Naturally, you should start by connecting the tubes to the air conditioner modules. It is better to do this with an external block first, because. there is a possibility that the track will have to be moved a little, and it is easier to do it indoors. In general, nothing complicated — just tighten the nuts with an adjustable wrench with the force specified in the instructions. If the previous calculations are correct, then the lines will easily reach from block to block, and there will be no problems with their connection. Otherwise, you will have to redo almost half of the work on installing the air conditioner.

Air extraction with a vacuum pump

Actually, this procedure is the basis for the safe and stable operation of the refrigerant in the split system. To carry out vacuuming, follow the following sequence:

• Connect the gauge manifold to the service port. Usually the connection is made to the low pressure outlet of the apparatus, but there are models in which the connection can be made in two fittings.
• Connect the vacuum pump to the manifold. The connection is made to the central fitting of the manifold.
• Open the valve of the fitting of the gauge manifold connected to the unit, If the manifold is electronic, then turn on the gauge manifold, and then the vacuum pump.
• The vacuum indicator is a value close to -0.1 MPa on the manifold display. This will happen after about a few tens of minutes of pump operation.
• Close the manifold valve and turn off the pump.
• See if the pressure builds up in the system. If after a sufficient time it does not rise, we recommend that you open the valve again and turn on the vacuum pump.
• After 10 minutes of operation, close the valve again and turn off the pump.

The work is completed and you can run the refrigerant into the route. It is recommended to disconnect the collector from the fitting after the refrigerant has been launched into the route.

Possible difficulties when vacuuming

The first thing you will encounter is the increase in pressure after the pump is turned off. The moisture that is still inside the pipe is to blame. Wait a while for the moisture to heat up and evaporate, turning into a gaseous state. Then turn on the pump again and remove it from the line.

The second option is when the pressure indicator increases after the first activation of the pump. This means that there is a small leak somewhere in the track.

The third difficulty is that in some cases the pressure increases after the second turn on of the pump. This already indicates a malfunction of the pump or manifold, leakage of the route, or an unsuccessful attempt to remove moisture from it.

Please note that it is impossible to completely remove water molecules from the line, but after the operation of the vacuum pump, it remains so small that this does not affect the operation of the system. In the event of a leak, carefully check the entire line, especially the junctions of the tubes. Continue vacuuming only after the leak is completely removed.