Why you have a need of a technician if you are itself capable of doing installation and repairing? You just need to follow these important guidelines and I am sure you never gonna have a need of any geek techs.
Always install an AC on a strong wall else there is always a fear of falling down of an AC.
Ac units requires at least 15 cm of space between the wall and unit to pass the air flow.
Similarly installation of an Air conditioners at an appropriate height is required to cool the room.
Make sure the wall bracket has given the slight tilt angle.
Place the indoor and outdoor units of an AC where no direct sunlight and water can reach.
Distance between the indoor and outdoor unit should not be greater else it will take time to cool.