LG Line Set Size?

NY_Rob

Lots to like about the LG Multi-F mini-splits, I'm leaning towards the LG vs. Daikin for my new system.

Looking at the "Piping Connections" page of the install manual for the LG LSN180HSV5 18k BTU Wall Mounted Unit and the LMU36CHV Outdoor Unit leaves me questioning the line set size just for the 18K BTU indoor unit (the 7K BTU and 12K BTU indoor units use straight 3/8" to 3/8" and 1/4" to 1/4" connections).


The condenser has four 3/8" vapor connections and four 1/4" liquid connections.
The 18K BTU indoor unit has a 5/8" vapor connection and 3/8" liquid connection
The docs for the 18K BTU wall unit call for a 1/2" vapor line and 1/4" liquid line.

The condenser comes with three LG supplied "Connection Sockets" that look like reducer/adapters to me.
Two for the vapor line: 3/8" to 1/2", and 1/2" to 5/8".
One for the liquid line: 1/4" to 3/8".

So, the way I interpret the manual is....

Condenser 3/8" vapor connection to short (field supplied) 3/8" section flare pipe to included LG 3/8" to 1/2" "Connection Socket" to 1/2" line set. 1/2" line set to included LG 1/2" to 5/8" "Connection Socket" to 5/8" indoor unit connection pipe.

Condenser 1/4" liquid connection to 1/4" line set. 1/4" line set to included LG 1/4" to 3/8" "Connection Socket" to indoor unit 3/8" connection pipe.

FWIW- this particular run for the 18K BTU wall unit will only be about 20' or so.
So it seems a 1/2" x 1/4" line set would be the right choice for the 18K BTU indoor unit?
The determining factor for the line set size seems to be table 25 "Indoor Unit Pipe Size"?

EBEBRATT-Ed

It looks like you have it right. I wouldn't deviate from what the mfg wants. Short runs are usually not an issue

bulldoglax

1/4 1/2 multi and 3/8 5/8 single zone. Comes with flare adaptors

NY_Rob

Thanks @EBEBRATT-Ed and @bulldoglax

Is it possible to connect the LG 3/8" to 1/2" "Connection Socket" directly to Condenser 3/8" vapor connection forgoing the short section of 3/8" to 3/8" I was going fabricate and use between the condenser connection and the 3/8" to 1/2" "Connection Socket"?

bulldoglax

Your confusing me, just run the line set 1/4 1/2 on the 18 k and the unit comes with adaptors for the appropriate transitions. I wouldn’t over think it unless you already ran the line set. in that case you are on your own I believe.

GW

We started brazing the adapters (couplings)

NY_Rob

bulldoglax said:

Your confusing me, just run the line set 1/4 1/2 on the 18 k and the unit comes with adaptors for the appropriate transitions. I wouldn’t over think it unless you already ran the line set. in that case you are on your own I believe.

Sorry, I could have been more clear....

The condenser vapor port is 3/8"
The line set is 1/2"
Can I just attach the LG 3/8" to 1/2" adapter right on to the vapor port of the condenser or do I need a short "transition" 3/8" length of pipe off the vapor port then connect the LG 3/8" to 1/2" adapter to that?

Don't have any of the parts yet. Just a list and some of the tools and install manuals.