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Dual zone mini split install?

bzinsky

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Just wondering if anybody knows the difference in installation method. I have installed a few single zones.

Is there anything special with the dual zones? Like I guess I'm wondering if the linesets are run like one big system that is vacuumed and pressurized or they have to be done independently.

I can figure most of it out on-site, but I'm ordering the units and don't want to be missing a tool or something when I get there. I have everything needed for single zone units.

Brand is LG if it matters

Thanks in advance
 
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bzinsky

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actually another separate question

This is the one I'm probably going to get

http://www.supplyhouse.com/LG-20K-2...SEER-Ductless-Dual-Zone-Heat-Pump-Package-918

the 18k btu indoor unit has 5/8th vapor and 3/8th liquid lines

yet the outdoor unit connections are 3/8ths and 1/4, hmmmm, wonder how that works. One would think the pre-charge in the unit would be severely effected by increasing the line-set size.

Why does this **** always have to get so complicated...sigh
 

walrus

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Just wondering if anybody knows the difference in installation method. I have installed a few single zones.

Is there anything special with the dual zones? Like I guess I'm wondering if the linesets are run like one big system that is vacuumed and pressurized or they have to be done independently.

I can figure most of it out on-site, but I'm ordering the units and don't want to be missing a tool or something when I get there. I have everything needed for single zone units.

Brand is LG if it matters

Thanks in advance
Line sets are done individually on the units I've seen but they are Fujitsu's not LGs.
 

Git

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With my Mr Slim - there were two line sets, but they connect to a common manifold. You can see the common service ports were the gauges attach to about 1/2 way up in the pic

With the electrical, there were additional connectors to attach the wiring to. This unit could actually handle three indoor units

Another thing to think about when purchasing a dual zone - is your outdoor unit big enough to run both indoor units or just one? (I have a 24k, 18k in the garage and 6k for my office) They did have a package with a 18k outdoor unit but I decided to go for the full 24k
 

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truckman5000

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actually another separate question

This is the one I'm probably going to get

http://www.supplyhouse.com/LG-20K-2...SEER-Ductless-Dual-Zone-Heat-Pump-Package-918

the 18k btu indoor unit has 5/8th vapor and 3/8th liquid lines

yet the outdoor unit connections are 3/8ths and 1/4, hmmmm, wonder how that works. One would think the pre-charge in the unit would be severely effected by increasing the line-set size.

Why does this **** always have to get so complicated...sigh

Not complicated if your a lic. tech.
Make sure the indoor units are designed for the condenser size.
Evac. the system.
Check the pre-charged ref. # rate. And look at your installed line set length/ size.
Compute to needed amount ref #/ ounces.
After psi test/ evac. weigh the ref. in.

If the line set is smaller/ bigger for the condencer port. They sell psi rated flare couplings that reduce.
Or you can braze reducing couplings.
:beer:

edit, we only install Mitsubishi, fujitsu, daikin. In that order. We replace alot of **** that others "install"....You may think its good...but its a **** shoot.
 
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bzinsky

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Not complicated if your a lic. tech.
Make sure the indoor units are designed for the condenser size.
Evac. the system.
Check the pre-charged ref. # rate. And look at your installed line set length/ size.
Compute to needed amount ref #/ ounces.
After psi test/ evac. weigh the ref. in.

If the line set is smaller/ bigger for the condencer port. They sell psi rated flare couplings that reduce.
Or you can braze reducing couplings.
:beer:

edit, we only install Mitsubishi, fujitsu, daikin. In that order. We replace alot of **** that others "install"....You may think its good...but its a **** shoot.

it's more difficult than you think for a consumer to find an hvac tech that will install them properly, I already went down that road. I just put them in myself now. Only ones I could find are the bigger companies that cater to higher end homeowners, or huge commercial jobs.

Anyway.... not looking to add refrigerant, just more tools I need. They come precharged and have lineset parameters in which you can use the factory charge and they are pretty darn lenient. LG rates the lineset length parameters for 1/4 and 3/8ths lines, but I can't find a spec on how increased lineset size effects the factory charge.
 
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bzinsky

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With my Mr Slim - there were two line sets, but they connect to a common manifold. You can see the common service ports were the gauges attach to about 1/2 way up in the pic

With the electrical, there were additional connectors to attach the wiring to. This unit could actually handle three indoor units

Another thing to think about when purchasing a dual zone - is your outdoor unit big enough to run both indoor units or just one? (I have a 24k, 18k in the garage and 6k for my office) They did have a package with a 18k outdoor unit but I decided to go for the full 24k

thanks, yeah the package I was looking at was the one in the link, LG engineering submittal and installation manual says they are compatible. What it doesn't spec is the change in the charge or lineset lengths when using the 18k btu unit, which uses thicker linesets.
 

chinboys

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Each line set, its evaporator and its connection to the LG condenser manifold is to be worked on independently.
That is what I did with my LG 4 zone 3 ton multisplit unit.
You will want to get a tank of nitrogen to pressure test your work.
When you draw and maintain a vacuum per set time is when you open both the liquid and gas lines.
You will need a 410 Freon manifold gauge set to check the pressure readings and temperature meter to more accurately decide if you need more Freon or less in lieu of the length of line set method.

Take your time , properly seat and torque the nuts.

I did the above 3 years ago with a neighbor who is a HVAC watching my work and the unit still works
You do realize this work voids all warranties on the unit.
 

Git

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When I purchased my Mr Slim through eComfort - they were great. If I had any questions, I just emailed them and they ran it past one of their 'engineers'

I did mostly everything myself but when it gets to the point of doing the final 'start up' - I looked at the cost of buying the additional tools needed (gauges, nitrogen tank, etc) compared to what it would cost to have a trained/authorized tech to do the startup. It cost me $300 for about 3 hours that he was there, but it should maintain my warranty and I felt better about the whole thing because he really looked everything over and checked my work.
 
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bzinsky

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Each line set, its evaporator and its connection to the LG condenser manifold is to be worked on independently.
That is what I did with my LG 4 zone 3 ton multisplit unit.
You will want to get a tank of nitrogen to pressure test your work.
When you draw and maintain a vacuum per set time is when you open both the liquid and gas lines.
You will need a 410 Freon manifold gauge set to check the pressure readings and temperature meter to more accurately decide if you need more Freon or less in lieu of the length of line set method.

Take your time , properly seat and torque the nuts.

I did the above 3 years ago with a neighbor who is a HVAC watching my work and the unit still works
You do realize this work voids all warranties on the unit.

Actually you would use a micron gauge for vacuum, the guys that don't know what they are doing (with mini-splits) read off the vacuum gauge on the manifold gauge set. This is precisely one of the issues I had with with most hvac techs.

Yeah it works, and they don't get a call back because there are no leaks, but is it operating at peak efficiency without confirming with a micron gauge? Who knows?

He could have attached one to his gauge set, but sounds unlikely since you didn't mention it and that's precisely what a lot of the long time hvac techs do.

Anyway, thanks for the advice, I think you're quadzone is actually setup different than the tri-zone, but no idea if installation method is different.
 
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bzinsky

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It cost me $300 for about 3 hours that he was there, but it should maintain my warranty and I felt better about the whole thing because he really looked everything over and checked my work.

I would hand over 3 times that with a smile on my face to get someone that knows what they are doing to install them for me.

Last bid I got before I said screw it was a hair under $2k per unit to install, for labor.
 

Git

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Don't get me wrong - I installed everything, the tech just checked it over and did the "startup"

I took pictures of everything and then emailed them to a couple of contractors that were Mitsubishi Diamond Certified (or whatever they call it for hvac contractors) and the guy I ended up using could see what he was dealing with it and treated it just like a service call
 

walrus

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Actually you would use a micron gauge for vacuum, the guys that don't know what they are doing (with mini-splits) read off the vacuum gauge on the manifold gauge set. This is precisely one of the issues I had with with most hvac techs.

Yeah it works, and they don't get a call back because there are no leaks, but is it operating at peak efficiency without confirming with a micron gauge? Who knows?

He could have attached one to his gauge set, but sounds unlikely since you didn't mention it and that's precisely what a lot of the long time hvac techs do.

Anyway, thanks for the advice, I think you're quadzone is actually setup different than the tri-zone, but no idea if installation method is different.

On a Fujitsu (I assume all others also) there isn't any need for a gauge set. There is only one place to hook a gauge anyway, low side and high side change depending on heating and cooling. Micron gauge and 0-800 psi gauge, short hose, ball valves, tee and adapters is what you need for mini split.
 

chrispyny

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albany, ny
With my Mr Slim - there were two line sets, but they connect to a common manifold. You can see the common service ports were the gauges attach to about 1/2 way up in the pic

With the electrical, there were additional connectors to attach the wiring to. This unit could actually handle three indoor units

Another thing to think about when purchasing a dual zone - is your outdoor unit big enough to run both indoor units or just one? (I have a 24k, 18k in the garage and 6k for my office) They did have a package with a 18k outdoor unit but I decided to go for the full 24k

Where did you get your Mr Slim ? Thanks
 

truckman5000

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it's more difficult than you think for a consumer to find an hvac tech that will install them properly, I already went down that road. I just put them in myself now. Only ones I could find are the bigger companies that cater to higher end homeowners, or huge commercial jobs.

Anyway.... not looking to add refrigerant, just more tools I need. They come precharged and have lineset parameters in which you can use the factory charge and they are pretty darn lenient. LG rates the lineset length parameters for 1/4 and 3/8ths lines, but I can't find a spec on how increased lineset size effects the factory charge.

UMMMN i know alot of my techs cant install them either. I do understand, I dont know why....just tring to help...if you read my post and googled acouple things you should know what i ment
 

truckman5000

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Actually you would use a micron gauge for vacuum, the guys that don't know what they are doing (with mini-splits) read off the vacuum gauge on the manifold gauge set. This is precisely one of the issues I had with with most hvac techs.

Yeah it works, and they don't get a call back because there are no leaks, but is it operating at peak efficiency without confirming with a micron gauge? Who knows?

He could have attached one to his gauge set, but sounds unlikely since you didn't mention it and that's precisely what a lot of the long time hvac techs do.

Anyway, thanks for the advice, I think you're quadzone is actually setup different than the tri-zone, but no idea if installation method is different.

Idiots pull out a micron gauge for a vac. test. Unless your pumping down a 20 ton system that a compressor blew up on.
A ductless..put a 7cfm vac. pump on it and it will be good in .2 mins.
I use a dig. gauge set that has micron on it.

Like i said idk what install you have. If your running max. lengths compute the difference, weigh in charge.
If your system dosnt have a min/max designed rate...distance=
"lenient"
Pump down syst. brake the vacuum with liquid 410a bringing to 10psi.
And open the valves on the condenser.
Turn the thing on...
If this dosnt make sense idk what to tell you. But if i started this system up for you and you asked me for the stuff you said, id walk away.
And yes i own a commercial company, but would treat you fair.
These go installed 2500-3000 a head here

Not needed but i usually 2x evac a multi head system. This is not needed though.
With everything ive said, me/ my guys have installed 2000+ of these systems a year. And ive done 3 commercial systems this year with 20 indoor units a system.
Just tying to help. as you give no info,
 
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bzinsky

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Idiots pull out a micron gauge for a vac. test. Unless your pumping down a 20 ton system that a compressor blew up on.
A ductless..put a 7cfm vac. pump on it and it will be good in .2 mins.
I use a dig. gauge set that has micron on it.

Like i said idk what install you have. If your running max. lengths compute the difference, weigh in charge.
If your system dosnt have a min/max designed rate...distance=
"lenient"
Pump down syst. brake the vacuum with liquid 410a bringing to 10psi.
And open the valves on the condenser.
Turn the thing on...
If this dosnt make sense idk what to tell you. But if i started this system up for you and you asked me for the stuff you said, id walk away.
And yes i own a commercial company, but would treat you fair.
These go installed 2500-3000 a head here

Not needed but i usually 2x evac a multi head system. This is not needed though.
With everything ive said, me/ my guys have installed 2000+ of these systems a year. And ive done 3 commercial systems this year with 20 indoor units a system.
Just tying to help. as you give no info,

idiots pull out a micron gauge? Every single shred of evidence regarding these, including the training course I took at LG, said using a micron gauge for vac is important....

Also what did I ask for?

I don't want to deal with any of this to be honest, I just want to hire someone that is honest and does it the correct way and pay them a fair price.

Yes I pissed off the hvac contractors, but what else am I supposed to do, let them screw it up? I want to hire someone long term. Can't just let them do their thing with no oversite on the first one. You may be the worlds best hvac company, but I don't know that until I see your work.

Worst one was the guy told me I should just use the flares on the linesets. I kept saying that is a bad plan, and we should use the ones that come from LG and reflare them. I listened to him because he's the "expert". I would say about half of the connections leaked from this.

Why I think a micron is important. About 5 out of the 80 connections held the nitrogen with no noticeable loss in pressure and passed the bubble test. When I pulled the VAC, (I did 20 in 1 day) I was able to locate these bad connections just because of the micron gauge. The ones that had no leaks would pull down to 50 microns within 5 minutes, and then level off. I had 5 units that no matter what I did, the micron reading would not level off, found leak. These are leaks that were so small it'd probably take atleast a year for the system to show signs of not working.

Another hvac issue - had my trusted tech, who is no doubt an experienced pro, who I've been working with for a long time, go to repair a 20 ton system because I received a call the AC wasn't working. He said it was low and he put refridgerant in. I get a call 2 months later from the tenant that it's 95 degrees out and the air conditioner can't keep up. I call up the hvac tech, and you know what he tells me, I emptied what I had in the truck but didn't have time to go get more! He thought that was no big deal!

How much money did I lose in electric because that thing was low on refrigerant and could not keep up? It probably ran constantly! What if it had gone on like this for years? I think it just evolves into common practice over the years to simply ensure the system is working, and there is very little emphasis on efficiency since the person who is paying for the utilities will likely never know and be just as happy. I mean you do thousands of hvac installs, and everybody is satisfied, why the hell would you ensure it's running at peak efficiency....integrity?
 

truckman5000

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(Lineset oz/ft x total length) – (factory charge for lineset) = charge adjustment
Example 1: System has 15 ft of line set using existing ¼” liquid line.
What charge adjustment is required?
Formula: (.27 oz/ft x 15 ft) – (9 oz) = (-4.95) oz.
Net result is to remove 4.95 oz of refrigerant from the system

Example 2: System has 45 ft of existing c” liquid line.
What charge adjustment is required?
Formula: (.40 oz/ft. x 45 ft) – (9 oz.) = 9 oz.
Net result is to add 9 oz of refrigerant to the system

There is charts on line that have line size/ capacity. Thats what i said to google before.

Unit
Size

Liquid
Line
Diameter
 
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