Hi
In split air conditioner we have two units #1 is indoor unit and #2 is outdoor unit.
How much distance is acceptable between both units?

A minimum distance is always preferred. The longer the line set the more cooling loss you will have. If you look in the install manual that comes with every unit it will tell you the acceptable distances. It will also tell you that you may have to upsize the pipe that connects the two if over so many feet.

As a rule of thumb avoid going over 50 foot

Thank you all.
But in my application distance is about 30 meters so most appealing suggestion is to increase the pipe size.
But if we increase the pipe size then we have to charge more gas, in another way I am increase the load on compressor. So.
What do you think if I increase the power of my compressor(2 tons compressor into 2.5 tons)
Or
Should I replace my rotary compressor with piston type compressor?

Thanks
Mkk