mini split shortest lineset length?

[PoorOwner]

The current Mitsubishi products doesn't seem to list a lineset minimum length.

Although, I believe it won't work well with the condenser sitting right outside of the room, with the lineset cut to 6.5'-7'.

Does anyone know for sure? Just about every other manufacturer list a minimum 10', some less. I don't think there is anything about Mitsu that made them different in this aspect.

Does it matter too that it is a dual zone system, so placing the condenser to locate BOTH indoor units far away is inconvenient.

 

[Jackfre]

I don't know about Mitsu, but on Fujitsu we used to instruct 9' for 7,9, 12 & 15's. 12' on 24+. Make sure if you run additional line set to make the mins that you lathe pipe off in a serpentine fashion rather than a coil as the coil will trap oil.

 

[PoorOwner]

I don't know about Mitsu, but on Fujitsu we used to instruct 9' for 7,9, 12 & 15's. 12' on 24+. Make sure if you run additional line set to make the mins that you lathe pipe off in a serpentine fashion rather than a coil as the coil will trap oil.

Thanks, I have a 9' ceiling in one room, how high would you say it is good height to put the air handler? It looks like, if I put it at 7 feet, then it would use around 7 feet of lineset, it would not be too difficult to turn it sideways and add a couple foot.

I don't know.. if the line length count the 20" sticking out of the evap already?

 

[walrus]

When I took a Mini split class Fujitsu was 10 ft but instructor said it was a noise issue more than anything else. Outdoor unit so close you will hear it. He said he installed several closer than that and had no performance issues. Whether it voids warranty I don't know??

 

[yeldogt]

The manuals available are extensive -- you should be able to get the information.

When I first saw the hyper heat units -- mitsubishi was showing them with the wall/floor unit as a replacement for radiators ... they mounted them w/ the condenser very close. So it must be possible.

 

[soob]

I asked the people who sell Pioneer and they said you could go as short as 5' but that you needed to remove an ounce of refrigerant.

 

[ticklechicken]

I asked the people who sell Pioneer and they said you could go as short as 5' but that you needed to remove an ounce of refrigerant.

I installed my Pioneer units with about 6-7' of line. No issues for me. The pressures were still within spec.

 

[PoorOwner]

I called Mitsubishi and it was easy to get a hold of a rep and then transferred me to tech support, I told him what model I want to install, he told me there no minimum length. I told him it's going to be 6 -7 feet he is not concerned at all

I have had a couple of mini splits including Mitsu, with uninsulated walls you could hear the outside unit sometimes, the compressor makes different tones depending on the load, sometimes the hum of fan on high. It's not too annoying but it is there.

 

[dw1]

I ordered mine with a 10' line set, I cannot hear much from the outside unit!! everything is working well- 87* outside and I can get 52* cool air out of it. I have only ran this an hour at a time, will be making the big move next weekend and it will be on fulltime after that, will see how it goes.

 

[Trey T]

y'all recover the refrigerant yourself?

 

[PoorOwner]

y'all recover the refrigerant yourself?

I looked at the manuals of different brands but they never say you need to recover some refrigerant for short runs, only that if it exceed a certain length then you add an amount per foot.

 

[Trey T]

You need to. Let me explain bc it will affect the capacity and SEER:

If the system is designed for 10ft length w/ 20oz precharge of R410a and you want to run 100ft (assume max allowable) long pipe to the head-unit. If the requirement is to charge 0.1oz/ft, then that's 10 additional ounces of refrigerant. Now years later you want to shorten the line, do you plan to keep the excess refrigerant or recover it?

 

[ticklechicken]

I looked at the manuals of different brands but they never say you need to recover some refrigerant for short runs, only that if it exceed a certain length then you add an amount per foot.

My manual said that I would need to remove some amount if I went below a certain length. I don't remember the exact values. To me, a pressure check seemed like a better way to determine if excess refrigerant was present. Is this the best way?

 

[yeldogt]

I called Mitsubishi and it was easy to get a hold of a rep and then transferred me to tech support, I told him what model I want to install, he told me there no minimum length. I told him it's going to be 6 -7 feet he is not concerned at all

I have had a couple of mini splits including Mitsu, with uninsulated walls you could hear the outside unit sometimes, the compressor makes different tones depending on the load, sometimes the hum of fan on high. It's not too annoying but it is there.

I installed my 30k 3 head on the wall w/bracket -- I can hear it -- believe it's resonating thought the brick wall.

My next one will be on the ground. Maybe the 9-12k units being so small don't vibrate -- the larger ones do. It's in no way offensive -- I'm the only one who hears it.

 

[Trey T]

My manual said that I would need to remove some amount if I went below a certain length. I don't remember the exact values. To me, a pressure check seemed like a better way to determine if excess refrigerant was present. Is this the best way?

No, no, no no, guys!!! STOP IT RIGHT THERE!!!!

Do not get into the realm of diagnosing the system. There are more to it than just reading the pressure. Just follow the charge amount (#oz/ft) on the install manual; the implication for recovery amount is the same.

Y'all are killing me. Many of us try to embrace the DIY movement with y'all, but don't get clever plz!!!

 

[PoorOwner]

No, no, no no, guys!!! STOP IT RIGHT THERE!!!!

Do not get into the realm of diagnosing the system. There are more to it than just reading the pressure. Just follow the charge amount (#oz/ft) on the install manual; the implication for recovery amount is the same.

Y'all are killing me. Many of us try to embrace the DIY movement with y'all, but don't get clever plz!!!

I feel following the label or manufacturer instructions would be best.

I think most tech just trust the factory charge is going to be close. On my label, says that amount of factory charge is good for up to 131 feet without adding, after that add 1.08oz per 5 feet. It doesn't say need to take out any R410A for less than that 131 ft.

If it has previously been added or leaked, then verify the charge is in order.

 

[justinjoyal]

Installed many units with linesets of 6-7' or so. No recovery. No problems.

As it was mentionned it is a noise concern more than anything.

 

[dw1]

Installed many units with linesets of 6-7' or so. No recovery. No problems.

As it was mentionned it is a noise concern more than anything.

Not if your hearing is as good as mine...

 

[soob]

y'all recover the refrigerant yourself?

Of course not. I hired a professional. He hooked the hoses up, purged them, then removed them. $300.

 

[ticklechicken]

No, no, no no, guys!!! STOP IT RIGHT THERE!!!!

Do not get into the realm of diagnosing the system. There are more to it than just reading the pressure. Just follow the charge amount (#oz/ft) on the install manual; the implication for recovery amount is the same.

Y'all are killing me. Many of us try to embrace the DIY movement with y'all, but don't get clever plz!!!

I had an a/c guy come out to do the evac and charge. Just reporting what he told me.

 

[PoorOwner]

I installed my 30k 3 head on the wall w/bracket -- I can hear it -- believe it's resonating thought the brick wall.

My next one will be on the ground. Maybe the 9-12k units being so small don't vibrate -- the larger ones do. It's in no way offensive -- I'm the only one who hears it.

Pretty much there is only 1 stand available for that size unit, it's model quick sling QSMS1201. I don't need it too high because there is no snow here, but it keeps the area clean and the gardening crew damaging it.

It's a 240V appliance running 20 amps or more.. it's got to make a little noise.

 

[Jackfre]

When the inverter 410A units came out, as the Rep I was trained on the minimum line set length. We were initially told that it could create noise issues. Cool, if they say so, I get it. A couple years later I was at one of the big National trade shows speaking with one of the Japanese engineers. I wanted a little more info on the min-line set deal so I asked him, "ok, I understand that the unit can make more noise, but what is the noise?" He said, "it is the compressor tearing itself apart...slowly." Pipe them as you want to, but...