Proper procedure to install air-cond?

Here is the procedure I copy pasta from forum.lowyat.net:

Anyway do take note of the following when your aircon tech comes to install your aircon.

I have noticed a lot of aircon techs didn't do a good job. They should at least vacuum pump the refrigerant lines + each fan coil unit and check for leaks before releasing the refrigerant. Without doing the vacuum pump evacuation, the moisture in the air will contaminate the system and the compressor will not function efficiently. It will also lead to premature wear and tear. The vacuum evacuation process should last at least 30 minutes for a thorough moisture and air evacuation.

On the other hand, a lot of technicians tried to save materials costs by using thinner copper tubings, brazing it with soft solder. The thinner tubings will cause more flow resistance and thus wasting the power. Thinner tubings also have the potential to starve the compressor of refrigerant and lubrication, leading to overheating and premature wear and tear.

Make sure they use at least a 80 core cable (not the very thin type) when wiring up the system. They should connect the aircon to a dedicated circuit breaker, not sharing it with other power plugs or lightings.

The temperature of the system should be measured after it has been running for at least 15 minutes in cooling mode with high fan speed and lowest temperature setting. Measure the temperature on the fan coil air intake and air outtake. The temperature difference should be at least 8 deg.C for Panasonic models. Different models come with different specifications.

Make sure your aircon tech does the above - otherwise they're not doing a good job. Another thing, offer the aircon tech a cold drink. This will give them some motivation for a good job.