Notes when installing VRV central air conditioning system

Along with the development of the country, a series of projects have sprung up, many contractors in all fields of activity. Ensuring the quality of the project requires contractors to have a team of good technical staff and besides that, constantly train and update technology to the installation staff. For refrigeration contractors, after the VRV central air conditioner was launched on the market with many new and modern features, a product that many consumers trust and use. That requires construction staff to have a firm grasp of the installation to bring the best quality.

Normally when installing a central air conditioning system for a project, we need to carry out the following main steps: Install copper pipes waiting in the wall or through the wall, install the condenser, hanging bar, install gas pipes, install condensate pipes, install the duct system, install insulation, run control wiring, install the condenser, test pressure, vacuum, and run the machine to charge the gas.

 

It is a general modeling process that must be done, but besides that, we need to pay attention to many things that, if not paid attention to, even though small, will bring trouble later. For example, when installing a waiting pipe through the wall, we should pay attention to the slope of the condensate pipe, installing the air conditioner, we need to check the machine model carefully before proceeding to install to avoid errors after installing the machine, the hanging bar has the right distance, the gas pipe is installed according to the rules of dry, clean, and airtight. These things are very small, but the consequences will be very large.

 

Next, when installing the gas divider - REFNET joint, it is necessary to note that the distance when the connecting pipe turns left is at least 500mm and between two gas dividers is at least 1000mm. Because if the bend is close to the gas divider, the gas velocity running in the pipe can cause noise. Do not install REFNET at an angle because it can cause the gas flow to be deflected, causing noise and causing the system to not work properly. Make sure to install the divider horizontally.

An important thing to note about the installation size of the water trap for the air conditioner, at the water trap location, remember to attach the drain button (included with the machine) to clean the water trap as shown below.

The relationship between the inner diameter of the main condensate drain pipe and the allowable flow rate when using a common drain pipe (with vent) is shown in the following table:

After the pressure test, we proceed to vacuum. To vacuum effectively, we should note the following when choosing a vacuum pump: Choose a pump that can reduce the pressure below -100.7 kPaG (-755mmHg) and choose a pump with a relatively large discharge flow. We should use a pump with a minimum flow of 40 l/min. There are usually two vacuum methods, one is the conventional type and the other is the special vacuum type.

Normal vacuuming is a one-time vacuuming after installing the machine, while special vacuuming takes a longer time and has more steps, especially in the rainy season, there is a risk of moisture condensation in the pipe or running the pipe without installing it immediately, so in the long run, impurities and dust can easily enter the pipe.

The two methods differ in the special vacuuming with an additional stage of breaking the vacuum state after the first vacuuming by injecting nitrogen at a pressure of 0.05 MPaG. Then vacuum again for the second time and leave it for at least one hour to check.

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