Central air conditioning installation steps

Central air conditioning installation is a concealed project, and the industry often says, "30% equipment, 70% installation." Whether the installation process is standardized directly determines the cooling effect, noise level, and whether leaks occur. The entire process typically consists of the following key stages:

I. Initial Positioning and Disclosure

Before the plumbing and electrical work begins, the installer, designer, electrician, and homeowner need to go to the site together to confirm the details. The key is to determine the location of the indoor unit (avoiding direct airflow onto the bedside and, as far as possible, avoiding wardrobes), the piping layout , and the controller location . It's also necessary to confirm whether an access panel has been provided and whether the drilling locations avoid the reinforcing steel bars in the load-bearing walls.

II. Indoor unit installation

Hoisting is not simply a matter of hanging it up; it must be secured with double nuts and shock-absorbing pads to prevent resonance during operation. The machine must be kept level; the condensate pan side can be slightly tilted , but the slope must not be reversed, otherwise the condensate will not drain properly. After hoisting, the machine must be covered with a dust cover to prevent construction dust from entering.

III. Refrigerant Piping Installation (Core Step)

This is the most demanding step in the process. The copper pipes must be welded using nitrogen shielding to prevent oxide scale buildup inside the pipes from clogging the system. After welding, nitrogen purging and pressure holding are required , typically up to about 40 kg, for 24-48 hours. The system is considered合格 (qualified) if the pressure does not drop. Simultaneously, both the copper pipes and condensate pipes must be tightly wrapped with insulation cotton, and the joints must be glued securely to prevent condensation and dripping later.

IV. Condensate pipe construction

Drainage pipes must have a slope of at least 1% and must not have any water traps. At the junction of main pipes , a slanted tee must be used, not a T-tee, otherwise backflow is likely. After installation, a drainage test must be performed by filling the pipes with water to check for smooth flow and leaks.

V. Vacuuming and Refrigerant Charging

After the pressure test is passed, use a vacuum pump to evacuate the piping to remove air and moisture. The evacuation time should generally be no less than one hour. Afterward, charge the refrigerant precisely according to the weight indicated on the machine's nameplate using an electronic scale ; do not add refrigerant by feel.

VI. Air vent installation and commissioning

After the ceiling installation is complete, install the return air vents and supply air vents. The supply air vents must not be obstructed by light troughs, otherwise hot air will not be able to escape. Finally, power on the machine for a test run, measure the supply air temperature, check the noise level and drainage, and teach the homeowner how to use the controller.

A few details where you might easily make a mistake:

Don't forget to leave an access panel : it's usually next to the return air vent, and its size should be no less than 350×350mm. Otherwise, you'll have to remove the ceiling for future repairs.

Make sure you don't mix up the signal cables : The signal cable from the indoor unit to the outdoor unit must be a shielded cable and cannot be run in the same conduit as the power cable, otherwise it will interfere with communication.

Keep a close eye on the pressure holding process : Many construction teams hold the pressure for a few hours and then leave. The proper practice is to hold the pressure until the renovation is completed and before starting the machine, so that any leaks in the pipes can be detected in time during the renovation process.