Opinions on mini split outside unit mounting from those who have done it already!

[dbsoundman]

Hi all, I'm finding lots of speculative information about where to place the outside unit for a mini split around the internet, but not a lot of information from people who have already done it and live with it currently. I'm hoping to get some opinions and experiences to help me figure out the best location for the outside unit.

I'm placing the inside unit on the back wall of the bus above the rear door; that's the only place I can put it. From there, I have three potential locations for the outside unit:

1. Underneath the bus on the driver's side between the front and rear wheels. This will involve cutting out the side for access and ventilation, which is fine. I feel like this also provides the most protection from road debris. However, I will most likely have to extend my lineset to reach this spot and I'm not sure quite how to do that yet; I was kind of trying to avoid that complication.

2. Underneath the bus on the driver's side between the rear wheels and the rear of the bus. This will also involve cutting out the side for access and ventilation. I'm concerned about rocks and debris being kicked up from the rear wheels, as well as hitting the unit if I go up a steep(er than anticipated) incline. However this would not require lengthening the lineset.

3. On a bracket above the rear door. No cutting required, but some specialty bracketry is required. I'm thinking I will also need some sort of wind shield to protect the back of the mini split from the air coming off the roof of the bus. This will make for an extremely short lineset, which is good. I'm mostly worried about too much wind/exposure in this position.

I'd love to hear your opinions and experiences!

 

[fo4imtippin]

Following. I am still trying to nail down where I want to put mine. My preference is above the backdoor, but sometimes that looks tacky..



As far as extending the lineset. I did it at my house with a Daikin. The factory charge was good for 12-50ft of lineset. Your manual should have that spec listed. Just buy a longer lineset if needed. If you are doing all the work yourself, I recommend reflaring as the factory flares are usually junk. You also want to use the flarenuts that came with the mini split as they are a certain match.

 

[Tejon7]

Also following. I had only one reasonable space for the outdoor unit - basically option #1 in your list. Everything is in place and I'm just waiting for a weekend without rain to crawl under the bus and install it all. I am really hoping that those with experience don't poo-poo option #1!

In your case, I'd be sorely tempted by option #3 for simplicity's sake, but I think the aesthetics would ultimately rule out that location for me. Not that any of our rigs will win a beauty pageant, but a giant condenser unit on the back is like a mullet for a bus.

 

[Iceni John]

I have a Pioneer 12K minisplit with heat pump, and the outdoor unit fits (but only just!) under the floor above the front axle. I previously had my electric air compressor there, but I moved it to a new location under the floor with a separate Velvac air tank below the driver's seat. The A/C unit sits on two crossbeams made of thick-wall 1" square tube inside 1.5"-wide channel, hanging from the lower frame rail by four Gr.8 1/2" bolts, with 5" spacers between the frame rail and crossbeams. There is about 1/2" above the A/C to the underside of the floor above it, and I made a new access hatch in the floor above the A/C that mimics the original hatch above the fuel tank that's a few feet away. I was worried that the front axle could possibly hit the underside of the A/C when driving over big undulations at speed, but a simple sliding-stick gauge shows that there's several inches of space there even when driving over the worst bounces. Lowering the A/C down into its space was a PITA, but it's now secure, out of sight, easily accessible if needed, gets lots of air when driving and is shaded when parked, doesn't take up any valuable space elsewhere, is close to the indoor unit, and out of range of any stones kicked up by the front tires. So far, so good!

John

 

[dbsoundman]

I have a Pioneer 12K minisplit with heat pump, and the outdoor unit fits (but only just!) under the floor above the front axle. I previously had my electric air compressor there, but I moved it to a new location under the floor with a separate Velvac air tank below the driver's seat. The A/C unit sits on two crossbeams made of thick-wall 1" square tube inside 1.5"-wide channel, hanging from the lower frame rail by four Gr.8 1/2" bolts, with 5" spacers between the frame rail and crossbeams. There is about 1/2" above the A/C to the underside of the floor above it, and I made a new access hatch in the floor above the A/C that mimics the original hatch above the fuel tank that's a few feet away. I was worried that the front axle could possibly hit the underside of the A/C when driving over big undulations at speed, but a simple sliding-stick gauge shows that there's several inches of space there even when driving over the worst bounces. Lowering the A/C down into its space was a PITA, but it's now secure, out of sight, easily accessible if needed, gets lots of air when driving and is shaded when parked, doesn't take up any valuable space elsewhere, is close to the indoor unit, and out of range of any stones kicked up by the front tires. So far, so good!

John

Good to hear! I am a little confused by your construction; is the unit hanging upside down, or do you have a U-shaped frame of some sort attaching it to the bus? You mentioned crossbeams and 1/2" bolts but that's all I understood.

 

[Flipmode-SKO]

I just did mine but haven’t put many miles on it so cannot comment on reliability. I decided to put the unit on the passenger side and have it exhausting outwards. This positions the line set hookups forward and the wrap around end of the condenser coil towards the rear. My thought process on it was the coil should be protected from debris/rocks while driving. I mounted it behind the rear wheel in a frame of 1.5” box and angle. I have the evaporator mounted on the rear bulkhead which made my 15(or 16’?) pretty good. It had a little slack but I don’t think it would have made it forward of the axle without extending. I thought I had pictures of it hooked up but all I found were ones test fitting the condenser. I could take some this evening if anyone was interested in the line set routing.

 

[kazetsukai]

Where I put mine:



I added a second unit to the left later which I hooked up a week or two ago.

 

[Nawbdy]

I'm a long way from installing a mini split in my bus but I've watched a lot of videos on YouTube by people who've done it themselves, lived with it and are reporting on it.

I note several members have responded to you in this thread as well. I wish I was far along enough for this to be a subject of study for me.

 

[Iceni John]

Good to hear! I am a little confused by your construction; is the unit hanging upside down, or do you have a U-shaped frame of some sort attaching it to the bus? You mentioned crossbeams and 1/2" bolts but that's all I understood.

No, it's not upside down - it wouldn't work if it were! The unit's mounting feet are bolted to two cross beams, and these cross beams are situated just ahead of and just behind the front axle: they hang below the frame rails by 1/2" gr.8 bolts that go through about 5" of spacers, i.e. the tops of the cross beams (and the bottom of the unit's feet) are about 5" below the bottom of the frame rails. There is about 1/2" between the top of the unit and the underside of the floor above, and plenty of space all around the unit for airflow when driving and when parked. Drilling 1/2" holes through the frame rails' lower flanges was not easy, but the holes are along the flanges' centerline where there is essentially no lateral stress, so I haven't weakened or compromised the frame rails' integrity; Crown drilled umpteen holes through frame rails for suspension etc, and everything's still OK after more than a quarter million miles!

 

[1dmpo]

On the back over door

I have a 9000 Pioneer heat pump unit and mounted the outside unit over the door on the back on 1 1/2 x 1 1/2 angle iron brackets that I welded with a 2" flat bar gusset on them. it's over the door just far enough that the door still opens and closes just fine, I cover with a small outdoor grill cover for going down the road. No problem. Inside unit is on a bracket hanging from the ceiling about five feet from the back wall of the bus, the line set that came with the whole set up is 16' long and I just made a somewhat large loop with it and attached it to the ceiling between the back wall and where the inside unit hangs. No problem, that's a closet area anyway. I have pictures but have no clue how to post them here.

 

[LargeMarge-TC]

I refer you to the Everlanders channel on YouTube.
.
This couple -- husband Jason, wife Kira the welder -- built their full-time live-aboard ExpeditionVehicle from the frame up.
Each part is hand-made, fabricated by them... and often, cranked-out alongside some rustic Canadian track or Central America camp.
.
Among their instructional videos is an excellent explanation of the Pepsi keg water system we used for a couple-three decades.
This simple system eliminates leaks, pump noise, funkiness... while offering substantial benefits.
.
Apparently, husband Jason is some kind of electronics genius, and re-builds everything... including re-manufacturing the MaxxAir fan to eliminate the brushes.
.
Irregardless, to your point, they mounted their outside half of the split on the rear wall:

.
You could just watch that one video, all your q answered.
You might benefit from watching most of their videos.

 

[DavidVT]

Under!

I spent years in the middle east, dusty and hot, working around mobile medical equipment.
Most of the split unit cooled units (lower sterile requirements) had the external unit(s) underneath in the open or in lower open rear side compartment.
They often looked horrid but ran well.

 

[Bluthebus00]

I did something similar. I have a universal mounting bracket bolted to the frame of our bus behind the rear axle and mud flaps. I installed retractable steps in front of it so when the steps are open it can breathe nicely.

Worked out great and is also hidden. I also have able a 1/2" of clearance between the top of my pioneer unit and the floor.

 

[DrDanger]

How not to do it

Our inside unit is located in the same location as yours. I mounted our outside unit underneath the bus behind the propane tanks which are behind the rear axle. It worked for us pretty well, except for one particularly rough BLM spot near Zion NP. I had extended the rear bumper to make a small deck on the back of the bus and I built a pretty beefy hitch below that, knowing that it would likely drag on the ground. The bottom of the mini split is above the line between bottom of the hitch and the bottom of the rear tires (see diagram).

I dragged the hitch on several occasions without damaging the mini-split (my appologies to the Cameron, LA ferry for tearing up your deck). However, this does not account for wicked big pot holes and ruts. The incident below caused my wife to dub the bus "The Dirt Surfer".

The good news is that the mini split survived and ran for another month while we finished our trip. Before we head anywhere rough again I will be moving it out of harms way. I am thinking I could put it on the rear deck and disguise it enough to not look super ugly.

 

[Rucker]

<snip>
I am thinking I could put it on the rear deck and disguise it enough to not look super ugly.

Same plan here. I have a rear deck (30" extension) that accommodates a truck toolbox, and the condenser will go above that in the center, just below the rear window.

I am worried it will look janky, and am thinking of some formed fiberglass 'wings' that partially enclose it and visually tie things together.

If it's janky at first, so be it.

 

[Desertsparky]

We only had 14 days to do our conversion before leaving for a funeral so it qas all rushed but we just put ours on the roof. We are roughly 3500 miles into our trip with only one scare. It is 12' 5" to top of unit. We had a bridge thay was 12'6". No damage but we went slow. We used a 9k btu unit on 30' bus and as does not reCh front very well. We use a fan midway which helps a lot.

 

[mmoore6856]

We only had 14 days to do our conversion before leaving for a funeral so it qas all rushed but we just put ours on the roof. We are roughly 3500 miles into our trip with only one scare. It is 12' 5" to top of unit. We had a bridge thay was 12'6". No damage but we went slow. We used a 9k btu unit on 30' bus and as does not reCh front very well. We use a fan midway which helps a lot.

12.6 is the legal height allowed thru not the actual height of the bridge.

 

[DeMac]

Now Available on Google

12.6 is the legal height allowed thru not the actual height of the bridge.

------------------------------------

fhwa.dot.gov freight publications size regs

- I sourced the information below from the Federal Highway Administration. (Link above)

In 1982, Congress established minimum length standards for most commercial truck tractor-semitrailers. There is no Federal vehicle height requirement for CMVs.

States may set their own height restrictions. Most height limits range from 13 feet, 6 inches to 14 feet, with exceptions granted for lower clearance on particular roads.

 

[Jolly Roger bus 223]

the short bus i am building will get a 9000btu mini.
should have been a rooftop in my opinion?
but i am just the builder.
my outdoor unit will not fit under the skirt or would already be there.
can not put it above the rear door because it is a fibreglass end cap and even trying to fabricate something from the interior steel to the fibreglass endcap for support i wouldnt like because it would severly limit and cover wiring access if not compromise some wiring from chaffing.
my option is to put it on the lower portion of the back door.
i have found stainless steel braided refrigerant lines at 3 feet long each so my plan with them is to as well as the electrical is to use the flex to make the connections but to make a loop that will move with the door and run the piping/tubing up to the rear cap in a line hide idea so it always has access.
and use braided lines just inside where the indoor unit will hang and use ball valves with shraeders and braided lines again to connect because it will be over my wiring access. and i dont like that but its where the owner wants it.
but i will make it moveable without dropping any charge and if need be able to isolate and drop the indoor unit minimal charge.
but thats my situation.
underneath definitley road debris cage and the coil will need frequent cleaning so design for access to clean and fin straitening from smaller debris.
good luck
for some of my decisions? i know the owner and her bus will only go to some one else if she is in another state and needs it fixed within her 3-months at a time away from home. yes she is my wife but this is hers and she is footing the bill for everything to get exactly what she wants.
years ago she was an architect and the housing market fell now she is a traveling lab tech all over the place.
this short bus will help her pocket most of her housing per diem. but some of the places she goes pay for the housing. so she can just drive her car and leave me the bus to fix/check or whatever.

 

[Nawbdy]

the short bus i am building will get a 9000btu mini.
should have been a rooftop in my opinion?
but i am just the builder.
my outdoor unit will not fit under the skirt or would already be there.
can not put it above the rear door because it is a fibreglass end cap and even trying to fabricate something from the interior steel to the fibreglass endcap for support i wouldnt like because it would severly limit and cover wiring access if not compromise some wiring from chaffing.
my option is to put it on the lower portion of the back door.
i have found stainless steel braided refrigerant lines at 3 feet long each so my plan with them is to as well as the electrical is to use the flex to make the connections but to make a loop that will move with the door and run the piping/tubing up to the rear cap in a line hide idea so it always has access.
and use braided lines just inside where the indoor unit will hang and use ball valves with shraeders and braided lines again to connect because it will be over my wiring access. and i dont like that but its where the owner wants it.
but i will make it moveable without dropping any charge and if need be able to isolate and drop the indoor unit minimal charge.
but thats my situation.
underneath definitley road debris cage and the coil will need frequent cleaning so design for access to clean and fin straitening from smaller debris.
good luck
for some of my decisions? i know the owner and her bus will only go to some one else if she is in another state and needs it fixed within her 3-months at a time away from home. yes she is my wife but this is hers and she is footing the bill for everything to get exactly what she wants.
years ago she was an architect and the housing market fell now she is a traveling lab tech all over the place.
this short bus will help her pocket most of her housing per diem. but some of the places she goes pay for the housing. so she can just drive her car and leave me the bus to fix/check or whatever.

I have no experience of my own but reading your post reminded me of a YouTube video I watched once of a guy who mounted his mini split on a pedestal he built of square tube. It was essentially 2 pieces of square tube that rose from the bumper/frame topped by a shelf where the mini split sat. The weight was borne by the frame/bumper.