Maximum Lineset solutions

branimal

I am looking at different 4-zone (39k 9+9+9+12) heat pump mini-split systems for installation on a 3rd floor apartment. Two of the four zones are quite far from the outside unit. One run is 90ft away and the other is 80ft. Mr Cool states the maximum distance per indoor unit is 73.8ft. The overall maximum lineset is 221.5ft. I'm at 262ft. (1st pic)

Based on a chart I found, Mr. Cool mini-splits allow for the longest lineset runs in comparison to other brands. (2nd pic).

Mr Cool maximum lineset chart (3rd pic).

Is it possible to add additional refrigerant to accommodate my longer lineset requirements? Or am I bumping up against the limits? Any recommendations to handle my situation?

I emailed Mr. Cool last week. No word back yet.

pecmsg

Exceeding manufacturers recommendations never works out good. 

I recommend only 2 heads per outdoor unit. 

Stay with known brands. Mitsubishi, Fujitsu, Daikin. All the other cheep knockoffs are garbage. 

GGross

LG 3-ton RED systems with branch boxes can have 475.7 total feet of piping, so the numbers from Mr. Cool are definitely not correct (what a shocker!)

Do not install a mini split outside of manufacturers specs, ever... You will have a bad time, and your warranty will be denied. Don't DIY a multi head install... unless you are licensed. Tech support will most likely not talk to you if you do not have all the required tools of the trade at hand.

Stick with the Japanese/Korean made mini split units. Mitsubishi, Fujitsu, LG, Daikin.

I would be comfortable with a single zone Mr. Cool, but would never consider the cheaper brands where heating is needed, or on multi head systems due to cost. You might save some money upfront with Mr. Cool, but when the parts break good luck on warranty.

branimal

I read thru each of the aforementioned brands documentation on maximum total lineset:

Daikin 230'
Mitsubishi 230'
LG 246'
Fujitsu 230'.

If I eliminate the deck in the backyard (hasn't been built - it was a nice to have idea), I can stay within the max total lineset length for each manufacturer.

I called up a few LG pro installers. Waiting to hear back from them.

mattmia2

What about 2 outdoor units in different locations?

GGross

To add on to what @mattmia2 is suggesting. Brands may differ on this slightly, but when you are reading a multi split outdoor units capacity they usually give some variation of "MINIMUM-RATED-MAXIMUM" and one really important thing to keep in mind is that "minimum" number, and it's relationship to the connected indoor units. Generally the more total connected capacity an ODU multi unit has, the higher the "minimum" will be, this is not usually posted in general spec sheets etc, and can sometimes result in systems that don't perform as desired, this is most noticeable in a system where your smallest heads will also be oversized for the space they are in.

So while a unit may have a listed "minimum" of 12k, that is usually only the case when you have the minimum allowable connected capacity attached to the ODU, as soon as you connect more capacity, that minimum number will go up, which can further exacerbate an already oversized IDU head if the system must now run above that units capacity at a minimum

branimal

I like the idea of 2 outdoor units or an LG 3-ton RED systems with branch boxes (prefer the latter). This would allow me to keep the deck in the backyard.

It looks like there are substantial rebates being offered by both ConEd (local utility) and NYS.

I contacted licensed reps from all four major companies (Mitsu, LG, Daikin, Fujitsu). Waiting to hear back still. These guys are in high demand apparently.

branimal

So i've done some research and I am getting close to pulling the trigger. As advised by others here, I'm going with two dual zone systems to power the top floor. The line set limitations are solved by two separate outdoor units. One in the front and one in the back.

I've only been able to get one licensed rep onsite (Fujitsu) and I've been texting/calling him to get a quote for two weeks. Radio silence. The Mitsubishi rep is scheduled for the end of July. These guys are booked solid I guess or they don't want the job.

I've looked into some other brands (not the big 4 - mitsubishi, fujitsu, daikin, lg) and read good reviews on Senville. I've gotten an English speaking tech on the phone each time I call. Great prices with line set included (I think we're not supposed to talk about actual prices here). Line set is darn expensive.

I'm looking at two 18k outdoor units to go with the following indoor units:
1. 9k / 9k
2. 12k / 9k

The plan is to run the line set, wiring, and condensate down the stud cavities and punch out on the first floor to the final install location. I'll probably replace the flimsy condensate line with 1/2" or 3/4" pvc. That will allow me to control the pitch when I'm going horizontal.

Any thoughts, criticisms, etc? Anyone have an opinion on Senville?

mattmia2

Looking at the price of linesets I think I would think very hard about buying coils of ACR tubing and unslitted k-flex.

pecmsg

Concentrate on the installing contractor. 

A bad install ALWAYS lead to problems!

ethicalpaul

I recommend only 2 heads per outdoor unit.

Stay with known brands. Mitsubishi, Fujitsu, Daikin. All the other cheep knockoffs are garbage.

There's nothing wrong with the top-tier brands of course, but I installed a Mr. Cool 3-head unit 4 years ago that has worked great. On one head the fan motor failed in year 2 and the internet-based seller, Ingram's, sent me a new motor under warranty.

And yes, for two of the heads they are almost certainly oversized for the space, but they modulate just fine. The fans keep running to circulate the air and they are very quiet.

I don't know why there would be a limit of 2 heads per unit if the system was designed to handle more than that (which these are). Maybe there's something magical about "2" that makes it better than "3" or "4"?

pecmsg

ethicalpaul said:

I recommend only 2 heads per outdoor unit. Stay with known brands. Mitsubishi, Fujitsu, Daikin. All the other cheep knockoffs are garbage.

There's nothing wrong with the top-tier brands of course, but I installed a Mr. Cool 3-head unit 4 years ago that has worked great. On one head the fan motor failed in year 2 and the internet-based seller, Ingram's, sent me a new motor under warranty. And yes, for two of the heads they are almost certainly oversized for the space, but they modulate just fine. The fans keep running to circulate the air and they are very quiet. I don't know why there would be a limit of 2 heads per unit if the system was designed to handle more than that (which these are). Maybe there's something magical about "2" that makes it better than "3" or "4"?

When something goes down what do you do?

branimal

ethicalpaul said:

I recommend only 2 heads per outdoor unit.

Stay with known brands. Mitsubishi, Fujitsu, Daikin. All the other cheep knockoffs are garbage.

There's nothing wrong with the top-tier brands of course, but I installed a Mr. Cool 3-head unit 4 years ago that has worked great. On one head the fan motor failed in year 2 and the internet-based seller, Ingram's, sent me a new motor under warranty.

And yes, for two of the heads they are almost certainly oversized for the space, but they modulate just fine. The fans keep running to circulate the air and they are very quiet.

I don't know why there would be a limit of 2 heads per unit if the system was designed to handle more than that (which these are). Maybe there's something magical about "2" that makes it better than "3" or "4"?

The 2-outdoor unit decision was based on me bumping up against the maximum line set limitation. 1 outdoor unit and 4 heads would exceed that limit. Nice to hear that Ingram / Mr. Cool honored the warranty.

JUGHNE

What will you use for heat?

branimal

JUGHNE said:

What will you use for heat?

The plan is to use the mini-splits for heat. The apartment is on the top floor. The roof is insulated with 3-4" of close cell spray foam and the walls are insulated with 3" of the same. Brand new windows. I do have CI Steam radiators throughout the apartment. I'll have the boiler kick on when it gets really cold.

JUGHNE

Smart move to keep the steam.

One needed repair part for a 4 zone system could be 2 weeks away. Another reason to not go with 4 heads on a single unit.

Could be in the cooling season where you have no backup for cooling.

branimal

JUGHNE said:

Smart move to keep the steam.

One needed repair part for a 4 zone system could be 2 weeks away. Another reason to not go with 4 heads on a single unit.

Could be in the cooling season where you have no backup for cooling.

Good point on the system going down in the summer time. I'll keep my old window A/C units on standby in the basement storage area.

ratio

It sounds like you've got the location & routing figured out already. The Mitsubishi design software is freely available here: http://mylinkdrive.com/USA/Software/Diamond_System_Builder?product&categoryName=Software. It's pretty easy to use, all things considered.

—huh! I just noticed they have a product selector too: https://discover.mitsubishicomfort.com/product-selector. Looks like it'll make it easy to figure out which unit you're wanting. It even lets you pick Trane-branded units!