LG mini split line question

[Kaizen]

I've purchased everything i need to do a professional installation on a 32k LG Multi zone. I have 18k heads and in the specs shown below it shows 1/2 for gas and 1/4 for the liquid. But the heads have 1/2 and what i'm assuming is 3/8 (.373 on calipers). Is this common or should I be using 3/8 line the whole way?

 

[mike93lx]

Why would they spec a 1/4" if you were supposed to use 3/8?

Use what's in the manual

 

[PoorUB]

I agree with Mike, use what the manual recomends. You can buy flare reducing fittings.

 

[Kaizen]

I agree with Mike, use what the manual recomends. You can buy flare reducing fittings.

I've seen manuals not updated when equipment has been. I wasn't sure if the unit needed the bigger 3/8 line for optimum efficiency and would be "slowed down" by the 1/4 flow. Perhaps refrigerant does not act like this?

 

[mike93lx]

I've seen manuals not updated when equipment has been. I wasn't sure if the unit needed the bigger 3/8 line for optimum efficiency and would be "slowed down" by the 1/4 flow. Perhaps refrigerant does not act like this?

If you want to ensure you have the latest info, download a new manual from lg's site or email tech support.

 

[pcmeiners]

"I wasn't sure if the unit needed the bigger 3/8 line for optimum efficiency and would be "slowed down" by the 1/4 flow. Perhaps refrigerant does not act like this?"

Believe the mechanical engineers were designing the line set size of 1/4" so that flashing ( liquid to gas ) does not occur in the liquid line before the expansion valve which could occur with a larger line size. If the design size was just about line pressure loss, you would be correct.

 

[Kaizen]

If you want to ensure you have the latest info, download a new manual from lg's site or email tech support.

LG doesn't talk to people unless your a pro. I did download their latest manual which is where i found this.

 

[Kaizen]

"I wasn't sure if the unit needed the bigger 3/8 line for optimum efficiency and would be "slowed down" by the 1/4 flow. Perhaps refrigerant does not act like this?"

Believe the mechanical engineers were designing the line set size of 1/4" so that flashing ( liquid to gas ) does not occur in the liquid line before the expansion valve which could occur with a larger line size. If the design size was just about line pressure loss, you would be correct.

That makes sense thanks.

 

[mike93lx]

LG doesn't talk to people unless your a pro

Sounds like they don't want your business. How do you expect to get support if something goes wrong?

 

[Kaizen]

Sounds like they don't want your business. How do you expect to get support if something goes wrong?

They want my business but through an hvac installer. I refuse to pay 4k for a system and then another 4k for installers when i know i can do 95 percent just as good. I've done 2 diy units and feel confident i can triple evacuate this system. If something goes wrong i'll have to
pay for a pro to look at it. My last 2 minisplits were the first gen mr cool's an both of those ran perfectly for years.
Just my mantra in life. Research, inquire, execute. Usually works out fine but i don't recommend for faint of heart.

 

[mike93lx]

They want my business but through an hvac installer. I refuse to pay 4k for a system and then another 4k for installers when i know i can do 95 percent just as good. I've done 2 diy units and feel confident i can triple evacuate this system. If something goes wrong i'll have to
pay for a pro to look at it. My last 2 minisplits were the first gen mr cool's an both of those ran perfectly for years.
Just my mantra in life. Research, inquire, execute. Usually works out fine but i don't recommend for faint of heart.

If they won't directly support you, they don't want your money.

That said, I've done the same type of stuff, so I appreciate the appeal. Can't say I've encountered companies that won't even talk to me, including those that only want their stuff installed by pros like aprilaire, aquacal and Mitsubishi.

 

[chinboys]

I have purchased two of my LG multi-zone systems from Supply House. They have a technical department you can ask questions about what the right-sized line sets are.
On my 36K unit, I use 1/4 for liquid and 3/8 for gas.
On my 48K unit, I feed 3/8 liquid and return gas on a 1-inch to a 4 port manifold that then uses 1/4 and 3/8.