Mini split line set sizing

Old 01-04-21, 05:57 PM
Thread Starter
Join Date: Aug 2017
Location: usa
Posts: 18
Received 0 Votes on 0 Posts
Mini split line set sizing

Background: I am planning to modify a family member's existing mini split system. Part of the job requires me to replace an 18k BTU Fujitsu indoor unit (ASU18RLF) with a smaller, 7KBTU indoor unit (ASU7RLF1). This is on a multi-connection outdoor unit (AOU45RLXFZ).
The problem: the current 18k unit uses a 1/2" gas pipe, but the 7k unit will require only a 3/8" gas pipe.
My hopeful solution: To keep costs down, I would like to keep the existing pipe, and simply add an adapter on the new indoor unit to step up the 3/8" flare connection to a 1/2". I do not want to buy and run a new gas pipe.
Question: Can I run a 1/2" gas pipe (with an adapter) to an indoor unit that requires a 3/8" pipe?
Old 01-04-21, 06:38 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 61,828
Received 1,473 Votes on 1,361 Posts
Sorry Mike...... any modifications or charging should only be done by an EPA certified technician. Since we have no way of knowing who is certified.... the administrators of DIY have requested no discussion in the forums on this topic.


Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: