I'm currently evaluating quotes for a multi-unit mini-split install on my older New England home. I am trying to educate myself about the particulars of the install and have a question for this board's experts.
One set of quotes involves different LG mini split models. Examining the installation instructions I noticed that the older less efficient models all specify that you either weigh in or recover some of the pre-charged coolant based upon the actual length of the refrigerant line sets. The newer more efficient models only tell you to verify that the gas side pressure is between a particular range (120-135 psig). The newer units all use an EEV and the older ones don't.
Is it, in fact, the case that units with an EEV can maintain efficiency with a wider range of refrigerant charges or is there some other reason why certain units don't ask that you precisely adjust the charge based upon line set length?