I am going to purchase Multi-Split air conditioning unit for my apartment that I am fully renovating at the moment. So it is the right time to make wholes in the walls etc.
The supplier is giving an outdoor unit that can sustain 5 indoor units, and I have 3 wall type indoor units and 2 concealed ceiling units (concealed under fake cardboard ceiling with linear diffuser to breath out the air).
One supplier included a separate drain pump for the ceiling units, the other supplier claims to have them built-in to the ceiling units. The wall units don't seem the have drain pumps according to specs.
Now my confusion: What is this drain pump? Is this required so that water doesn't drip from the outdoor unit or is required so that indoor units don't drip water? Am I suppose to get all the drain hoses attached to my plumbing? Is this where the pump is required? How far can I pump the water to reach the plumbing?
So far I have only used a single indoor and single outdoor unit scenario, and some hose seems to hang out from the outer wall dripping water to the street. Is this hose used by the outer unit or indoor unit?
As you can see I am conceptually confused as I don't understand the innerworkings. Sorry for chain of questions. I think the answer to all will be explained once you explain the drainage situation.
Thanks in advance