Inverter AC Installation: 7 Things Pakistani Installers Often Get Wrong

A correctly installed inverter AC will run for ten to twelve years with minimal trouble. A badly installed one will start losing efficiency in the first summer and fail outright in three. The difference is not the brand. It is the install. Here are the seven mistakes to watch for.

1. Wrong copper pipe size for the tonnage. A 1.5-ton inverter needs 1/4" suction and 1/2" liquid line as a baseline; 2-ton units need bigger. Some installers use whatever they have on the truck. Undersized piping starves the compressor and burns it out.

2. Skipping the vacuum step. Before charging gas, the line set must be vacuumed for at least 15 minutes to remove moisture. Moisture inside the system freezes at the expansion valve and slowly destroys the compressor. If your installer connects gas without a vacuum pump on site, refuse the job.

3. Outdoor unit in direct sun without shade. Direct sun raises the working temperature of the condenser by 8–12°C. A simple metal shade canopy adds five years of life and 10–15% efficiency. Many installers skip it to save thirty minutes of work.

4. Indoor unit too close to the ceiling. There must be at least 15 cm of clearance above the indoor unit so it can draw return air properly. Tight install = restricted airflow = ice on coils within a season.

5. Wrong drain slope. The drain pipe from the indoor unit must slope downward continuously at roughly 1 cm per metre. A flat or back-sloped drain causes water to pool and eventually drip from the front of the indoor unit onto your floor.

6. No torque wrench on flare nuts. Flare connections need a specific torque — too loose and they leak gas, too tight and they crack the brass. A torque wrench is the difference between a leak-free system and a Rs. 6,000 refill next year.

7. No pressure test before charging gas. The system should be pressurised with nitrogen and held for at least ten minutes before any refrigerant goes in. This catches micro-leaks at the joints. Skipping this step is the single biggest reason inverters lose gas in their first year.