Do air conditioners require a minimum length of piping?

[stovexxx]

I should have a 21,000 btu air conditioner installed,
the manual says to use at least 10 feet of tubing,
to avoid possible vibrations,
my installer says less tubing equals more efficiency, and there are hardly any vibrations.
Some say that the tubing length of at least 10 feet is also to "compensate" for the gas pressures.
The point is that the motor will be positioned exactly behind the internal unit, and it will probably be 5 feet of tubing,
what do you think?
Thanks

 

[Bristlecone]

I would trust the a/c design engineer’s information over what an installer says. I installed many ,but, never less than 20 ft apart. It just worked out that way. Virtually all residential systems come charged with refrigerant for a 30 ft line set.
The 10 ft line set will probably work. Get a guarantee in writing. Don’t pay him completely until the system has been totally tested.

 

[stovexxx]

I would trust the a/c design engineer’s information over what an installer says. I installed many ,but, never less than 20 ft apart. It just worked out that way. Virtually all residential systems come charged with refrigerant for a 30 ft line set.
The 10 ft line set will probably work. Get a guarantee in writing. Don’t pay him completely until the system has been totally tested.

yes, in the end we respected what the technical data sheet says, decentralizing the external unit, compared to the internal one by 10 feet👍

 

[Bristlecone]

Hey Big Daddy - that is a nice unit and a good clean install. Congrats