I was considering buying a cheap mini-split AC unit to cool a small room (10ftx10ft) over the summer now that we spend more time working from home. There are several units on the market. However I'd like to mount the two parts of the system pretty much back to back, one on the outside wall, the other on the corresponding inside wall, about 8-10 inch apart (I just have to check how thick is the stucco etc). However I read there is a 10ft minimum distance between the two units, and this would complicate the job a whole lot. What is the reason for a minimum distance? Too much final pressure of the pre-charged gas comes to mind perhaps?
The manual for the Pioneer mini split system I'm installing this weekend says the unit is pre-charged for 16 foot lines. For distances less than 25 feet the manual says no change to the refrigerant charge is needed. Nowhere that I can find does it say the pipes have a minimum length.
Maybe see if the installation manuals are available on the Internet for the unit you intend to purchase. They should have similar guidelines.
Well no there is not a minimum in any case I have seen. Now let’s consider what is practical the inside unit is normally required to be above the outside unit , the elevation is not specified, those that need more heating the inside unit will be close to the floor, others with more cooling or a mix are usually high with an inside unit that has a sweeping motion. But is that required? NO what is required is the drain for the condensate is below the inside unit. Many commercial compressors are above the evaporator the same can be true for a split system , the systems are shipped with a charge that will work within the specified lengths of line sets.