Mini Split Question

[Mr_Geenie]

Has anyone installed a mini split AC heat pump on the front of a dog nose school bus? I think the interior component would install just fine. Wondering where to mount the compressor.

My build has the "bedroom" right behind the driver seat, kitchen/bathroom in the middle and rear area for sitting/entertaining/TV etc.
Main entrance when parked is going to be through the rear of the bus.

I have a roof top AC available to me, but I would rather be able to use the emergency exit to access roof for a future roof deck and solar panel project.

[fo4imtippin]

You can buy long linesets. I had a 50fter for my house andmmy outdoor unit was precharged for up to 50ft.
Check the manual of the one your buying for limits. Otherwise, you have to have add 410a.
With that, it's up to you, you can fit them under the skirt or make a long lineset to the back.

[ChrisKatana]

I'm considering the same. with the inside unit above the windshield. haven't seen anyone install in that location yet.

Originally Posted by Mr_Geenie

Has anyone installed a mini split AC heat pump on the front of a dog nose school bus?

[HamSkoolie]

We came across a dog nose skoolie with a mini split in front. The compressor/condenser unit was mounted under the bus in the first part of the side wall that was open between the side and frame rail.

[cadillackid]

minisplits are not precharged for 50 feet.. however long lines are available and they work great.. long linesets wont hurt the compressor esp since your vertical rise is very low on a bus, you will want to top off the refrigerant though... it may cool fine with whats in there but the heat function will be reduced and inefficient unless topped off.. plus with long lines its imperative to vacuum it down to 500 microns or better..

[kazetsukai]

The lines for our split is roughly 45'-50'. Rear mounted exterior unit, front interior. Works great. Needed extra refrigerant and had the lines professionally vacuumed / installed.

[cadillackid]

Originally Posted by kazetsukai

The lines for our split is roughly 45'-50'. Rear mounted exterior unit, front interior. Works great. Needed extra refrigerant and had the lines professionally vacuumed / installed.

It blows hot and cold but is it running efficiently? Did the book say it’s charged for 50’? Do pressures match PT and sub cooling on spec?

My units “run” when low on charge too but they run best and most efficient when properly evacuated and charged.. and I back that up with data I record on power usage and PT measurements

[kazetsukai]

Originally Posted by cadillackid

It blows hot and cold but is it running efficiently? Did the book say it’s charged for 50’? Do pressures match PT and sub cooling on spec?

My units “run” when low on charge too but they run best and most efficient when properly evacuated and charged.. and I back that up with data I record on power usage and PT measurements

If you look at my build thread I've had nothing but glowing praise for this thing, its like magic. Again, professionally done. We had a vacuum pulled and held overnight, then gas filled to specification.



I have little to no faith for "DIY split installations", working with gas lines requires proper tools, processes, etc. I bought a nice unit for efficiency after all, why undermine that with a sloppy job. I have a second exterior unit mounted at this point but haven't installed the interior unit for it yet. That will be a much shorter run, around 10', but still will have a pro come out and do the lineset.

[cadillackid]

Originally Posted by kazetsukai

If you look at my build thread I've had nothing but glowing praise for this thing, its like magic. Again, professionally done. We had a vacuum pulled and held overnight, then gas filled to specification.



I have little to no faith for "DIY split installations", working with gas lines requires proper tools, processes, etc. I bought a nice unit for efficiency after all, why undermine that with a sloppy job. I have a second exterior unit mounted at this point but haven't installed the interior unit for it yet. That will be a much shorter run, around 10', but still will have a pro come out and do the lineset.

got it.. i was thinking this thread was about whether gas needed to nbe added when someone runs a 40-50' lineset.. my point was that a run it without adding freon results in lower efficiency.. ive got minisplits in my house I installed in 2009 and 2010 and they are fantastic.. mine are ducted into my normal ducting system of the house and i also have high praise for them.. they are the tops as far as im concerned when it comes to cooling and mild heating

[Mercuric Mind]

Hey Mr.G
I'm doing the same thing, putting a mini split above the windshield of the bus. I made a locker recessed into the side of the bus behind the driver seat for the outside unit. I had to move the chassis battery box forward in the process.

[ChrisKatana]

In for pics of the inside install when you get it in.

Thank you!

Originally Posted by Mercuric Mind

Hey Mr.G
I'm doing the same thing, putting a mini split above the windshield of the bus. I made a locker recessed into the side of the bus behind the driver seat for the outside unit. I had to move the chassis battery box forward in the process.

[Mercuric Mind]

Ya that may be a while, I'm on an island in the south of France until spring. I will continue the build when I get back state side. I have a build album of the work so far.
Here is a link if you are interested.
https://www.skoolie.net/forums/membe...lbums2129.html

[ABBus]

I'm curious. Why using a mini split, which is not built to resist to the vibrations of the bus while on the road, instead of a proper RV roof AC unit and diesel heater?
No criticism, genuinely curious.

[Mercuric Mind]

AABus,
For me I was looking for a high SEER unit so as to reduce the power consumption as much as possible. From what I have seen of RV units vs. Mini splits the internals are mostly the same and with some vibration dampening on the mount points I'm willing to gamble on the longevity vs a RV unit. I also did not want the roof unit as I plan to cover most of the roof with PV panels. What can I say, My complications have complications.

[cadillackid]

Originally Posted by Mercuric Mind

AABus,
For me I was looking for a high SEER unit so as to reduce the power consumption as much as possible. From what I have seen of RV units vs. Mini splits the internals are mostly the same and with some vibration dampening on the mount points I'm willing to gamble on the longevity vs a RV unit. I also did not want the roof unit as I plan to cover most of the roof with PV panels. What can I say, My complications have complications.

Minisplits internals are nothing like RV units. I once thought same about road vibrations but there are plenty of people with several years of near comitinuous travel that have zero issues with minisplit leaks / failures.

As for this last bus with a locker for the outside unit, I hope they plan to cut the rear out of that space or the outdoor unit will be stressed choking on its own hot air… they need unobstructed airflow and lots of it

[Mercuric Mind]

Originally Posted by cadillackid

As for this last bus with a locker for the outside unit, I hope they plan to cut the rear out of that space or the outdoor unit will be stressed choking on its own hot air… they need unobstructed airflow and lots of it

Good point!
And yes it will have venting on the back side and adequate spacing as per installation destructions state.

[Mercuric Mind]

Originally Posted by cadillackid

Minisplits internals are nothing like RV units. I once thought same about road vibrations but there are plenty of people with several years of near comitinuous travel that have zero issues with minisplit leaks / failures.

Thanks cadillackid.
That puts my mind at ease about the longevity issue.
I know I wasn't very concise in my comment about RV unit vs mini-split. I was thinking it terms of they both have compressors, fan, etc. Now I'm gonna say this my opinion but it seems to me that a lot of RV specific products are of a lesser build quality when compared to products designed for industrial or OEM applications. Perhaps due to the less stringent regulation.? IDK

[Mr_Geenie]

Thanks for all the great input and ideas.
I am in HVAC school right now. I knew I wanted a mini split over a rooftop unit because of serviceability. The rooftop ones leak freon, and as they are class 1 self contained units they need puncture valves to recharge, which also have a reputation for leaks.
Minisplits are type 2 residential units with much greater efficiency and reliability. They are designed to be used year round vs the roof top units that are intended for occasionall use.
Mini splits also have full service valves and connections. A mini split of comparable size and quality is about 1/2 the cost of a Dometic or Norcold roof top unit. And that is with my dealer doscount working at an RV dealership.

[cadillackid]

The only issue I ever encounter with minisplits are the crappy Chinese flares .. I used to re flare every one of them but lately I use flare sealer and never have an issue with any of them .. but yeah service valves are a huge plus as is the soft start and low noise factor vs a rooftop unit