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Mitsubishi Mini-split Branch Box question
Stoli
Member Posts: 10
Residential 5 port Mitsubishi branch box: PAC-MKA51BC
If only 4 of the 5 ports are used, does it matter which ones? The install manual sort of insinuates that you should use A, B, C and D and leave E unused, although it sounds more like a recommendation than a requirement. My installer used A, B, D and E and left C unused, presumably because port E has a 1/2" gas line (the other 4 are 3/8") and one of the inside units was larger and required a 1/2" line. That way, he didn't need to install a 3/8" to 1/2" converter pipe.
If only 4 of the 5 ports are used, does it matter which ones? The install manual sort of insinuates that you should use A, B, C and D and leave E unused, although it sounds more like a recommendation than a requirement. My installer used A, B, D and E and left C unused, presumably because port E has a 1/2" gas line (the other 4 are 3/8") and one of the inside units was larger and required a 1/2" line. That way, he didn't need to install a 3/8" to 1/2" converter pipe.
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Comments
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Does not matter which ports you use. Does not have to be sequential, at all. But, you have to select the correct addressing for the wiring. Every time I do a D box, too many months have passed and I can’t remember the exact process. It’s buried in my notes somewhere0
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Cheers Gary. I appreciate you taking the time to respond.0
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Thought its 15 and 51 (condenser first then box)0
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Probably important to note that there may be differences depending on the models, but in my case, I have a newer MXZ condenser and the PAC-MKA51BC branch box with 4 indoor units hooked up, so the addressing setup is:
Condenser: 51 (SWU2, SWU1)
Branch Box:
Address: 01 (SW12, SW11)
SW1: Active ports (A, B, D, E) set to ON
That effectively addresses the indoor units to
A : 01
B : 02
C : (NOT USED)
D : 03
E : 04
Gets a little more complicated with multiple D boxes, but the manuals are pretty good regarding proper addressing setup.
** NOTE: I'm not a Mitsubish Tech. **
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