Mini-split heat pump install in 34’

[SmokelessJoe]

Dan, I strongly advise mounting the compressor up against the trailer for the reason Iansk gives you above: weight balance and the fact that only 4” is needed. That will also provide a more pleasing, aerodynamic when in motion, Airstream conforming design.

Build a stand. If you modify the top of the tool box, ..maybe a hinge down the centre ? .., you’ll be able to access it. (Ask also if you really need the tool box).Going this way will not only improve looks and performance, it’ll end all the issues your’re having with the placement of the jack and the weight distribution system.

You can still see the photos of how the first mini split was installed on an Airstream on my main thread, referred to above. That layout has worked perfectly for 13 + years

[truckasaurus]

Great info Dan. I've got it stuck in my head that the lines need to go form the external unit up to the internal unit without a dip but if then can go down into the belly area that would be slick.

[TouringDan]

Originally Posted by SmokelessJoe

Dan, I strongly advise mounting the compressor up against the trailer for the reason Iansk gives you above: weight balance and the fact that only 4” is needed. That will also provide a more pleasing, aerodynamic when in motion, Airstream conforming design.



Build a stand. If you modify the top of the tool box, ..maybe a hinge down the centre ? .., you’ll be able to access it. (Ask also if you really need the tool box).Going this way will not only improve looks and performance, it’ll end all the issues your’re having with the placement of the jack and the weight distribution system.



You can still see the photos of how the first mini split was installed on an Airstream on my main thread, referred to above. That layout has worked perfectly for 13 + years

SmokelessJoe

I appreciate your strong recommendation, but I believe in my situation that locating it up front where the propane tanks were located is the best location for the following reasons:

1- It will fit there and it is actually similar in size and shape to the propane tank cover although it is actually smaller. The compressor is 31.5x22 with a frontal area of 633 square inches. The cover is 29x29 with a frontal area of 841 square inches, 33% more area than the compressor.
Now it is not very attractive, so I will hopefully design and fabricate an attractive cover that will also protect it from flying debris. My sister is a seamstress and I will certainly rely on her help designing and fabricating a cover. The cover will be fabric but will incorporate a metal rock shield.
This will require moving the electric jack forward (thanks Bubba), but this is doable. I need to move it probably 0.5”, but I will probably move it 1.25” to provide flexibility in the final location of the compressor (see photo).
I will need to design and fabricate an adapter plate to be secured to the top of the A frame and that the compressor will be bolted to. I have ordered a piece of 1/4x16x24 aluminum plate.

2- locating the compressor in front leaves about a 13.5” space next to the Airstream wall where I can install a single aluminum horizontal propane tank. A 20 Lb tank has a 12.25” diameter and a 10 Lb tank has a 10.375” diameter. I will need to design and fabricate a bracket to hold this while allowing access to the storage box underneath.
Now the front Airstream wall is angled forward. The 13.5” distance at the bottom is reduced to 10” at the top of the compressor (see photo)

3- the manual specifies a clearance of 12” behind the compressor for maximum performance. Other manuals indicate that the performance will be reduced by 10% with a clearance of 4”. I want maximum performance if that is possible. Remember that I am cooling a 34’ Airstream. I want the full 12,000 btu/hr cooling available, not 10,800 btu/hr.

Mounting the compressor next to the front wall may have been the best location for your trailer, but I believe that mounting it where the propane tanks were located is the best for my situation.

Dan

[SmokelessJoe]

Dan, you're a man of my own heart, providing good detail while sharing opinions.

An aluminum angle stand, located somewhere between the wall and the jack, could also serve as the holder for your tank, slipped in under the compressor, but enough said. You are on site and I am coaching from the sidelines.

You can make a travel protector for the coils by cutting an 18", or whatever the diameter is, circle from aluminum. You remove the 5 or 6 screws holding the grill, slip the disc in against the cowl, replace the screws.

Don't forget to remove the disc ( or cover) when you start the AC!

[Wabbiteer]

On the clearance spec - remember the recommendations are because they have no control about the general location, tucked into a hidey hole w/ stagnant air, rough surfaces and ground level with no upwards draft, flanked by adjoining outside units stacked in like sardines so each unit is breathing the exhaust of others...

The smooth aluminum panel with free-flow air from underneath and not much lateral obstruction before the endcap curves away, plus being in (generally) unobstructed prevailing winds and not tucked in an alley or somesuch...

If 4-inch just doesn't compute then maybe a slider tray to get a more manly 6-inches?

(I've been shopping split units seeking the high SEER and narrow condenser unit to hang on the back door of my diesel Promaster window van )


Edit: Where we can get > 5% savings is keeping the condenser coils out of direct sunlight... just a factoid.

[TouringDan]

Originally Posted by SmokelessJoe

Dan, you're a man of my own heart, providing good detail while sharing opinions.



An aluminum angle stand, located somewhere between the wall and the jack, could also serve as the holder for your tank, slipped in under the compressor, but enough said. You are on site and I am coaching from the sidelines.



You can make a travel protector for the coils by cutting an 18", or whatever the diameter is, circle from aluminum. You remove the 5 or 6 screws holding the grill, slip the disc in against the cowl, replace the screws.



Don't forget to remove the disc ( or cover) when you start the AC!

SmokelessJoe

Thanks for all your concern and input. You want to make sure that I have the best possible design and I appreciate that.
My plan is to have an aluminum shield that is the size of the front of the compressor (31.5x22) and incorporate this into the fabric compressor cover.

Dan

[TouringDan]

Originally Posted by Wabbiteer

On the clearance spec - remember the recommendations are because they have no control about the general location, tucked into a hidey hole w/ stagnant air, rough surfaces and ground level with no upwards draft, flanked by adjoining outside units stacked in like sardines so each unit is breathing the exhaust of others...

The smooth aluminum panel with free-flow air from underneath and not much lateral obstruction before the endcap curves away, plus being in (generally) unobstructed prevailing winds and not tucked in an alley or somesuch...

If 4-inch just doesn't compute then maybe a slider tray to get a more manly 6-inches?

(I've been shopping split units seeking the high SEER and narrow condenser unit to hang on the back door of my diesel Promaster window van )


Edit: Where we can get > 5% savings is keeping the condenser coils out of direct sunlight... just a factoid.

Wabbiteer

I don’t believe input air will be a problem.

Maybe I can come up with a shade or some kind of umbrella to protect the compressor from the sun to help gain maximum performance from the unit. Thanks for your comment.

Dan

[TouringDan]

Originally Posted by Wabbiteer

Edit: Where we can get > 5% savings is keeping the condenser coils out of direct sunlight... just a factoid.

Wabbiteer

Come to think of it, you have just provided another advantage of a minisplit heat pump over a typical RV heat pump installed on the roof. You won’t be putting a shade on the roof RV heat pump but you can put a shade on a minisplit to improve the performance.

Dan

[Bubba L]

Originally Posted by TouringDan

Wabbiteer

I don’t believe input air will be a problem.

Maybe I can come up with a shade or some kind of umbrella to protect the compressor from the sun to help gain maximum performance from the unit. Thanks for your comment.

Dan

Don’t know if you have a rock guard or not covering your front window. On our 55, I installed a rock guard and my boss made a shade cover for it with leftover Sunbrella awning material. It has elastic straps that installs in about 10 seconds. Maybe during the heat of the day the rock guard with awning material when opened will shade the condenser. Don’t know, just throwing it out there. You’ll still have the protective covering when traveling, of course.

[TouringDan]

I have a rock guard for the front window but I don’t know how much shade it will provide. I kind of like the idea of installing a removable umbrella to provide shade if it really will improve the minisplit performance. I will run a test as soon as I get my minisplit installed.

I suppose a regular heat pump would also have improved performance if it were shaded also. However, most residential heat pumps I have seen direct the airflow out the top. An umbrella may not work too well.

Dan

[OTRA15]

Originally Posted by TouringDan

I have a 95 Excella 34’ that I purchased about 5 years ago. I have recently started a complete interior and system rebuild of this trailer. The project thread is in the Excella 94-96 section and is titled Dan’s 34’ Makeover. I have always intended to install a mini-split in this Airstream and it is finally time to do it.
. . .

Great thread, thanks!

I have lived in small cottages with mini-split systems, and they are great, especially if you use the manual settings to customize the vane orientations, and fan speeds, according to the season and need for heat or A/C. A very small [independent] fan, on the other side of the room, can really help keep the room air moving in a large circle, to avoid too much cycling from the unit kicking on and off. This also makes the room temp more uniform L/R and Hi/Low.

Your project thread is here, for everyone's info:

https://www.airforums.com/forums/f25...er-124438.html

Peter

[truckasaurus]

More installation pics for your montage. Not mine, just one I saw on FB marketplace.

[TouringDan]

Peter- Thanks for adding my project thread here and thanks for sharing your experience with minisplit systems. I plan to have three Maxxair fans in the Airstream to keep the air circulating and keep the temperature uniform.

truckasaurus- Thanks for the photos of another Airstream minisplit installation. He must have his air handler on the front wall as I notice the extra refrigerant line coiled up under the compressor. I also notice that his solar panels may be adjustable to improve their solar performance.

Dan

[Iansk]

Originally Posted by truckasaurus

More installation pics for your montage. Not mine, just one I saw on FB marketplace.

This cat looks to be pushing the 4” minimum clearance a wee bit.
Also, that’s some lift on that trailer. Judging by the cinder block steps it has about 24” of clearance.

Regarding the coiled up line set, I shortened mine so it was a straight run instead of having all the excess coiled up.

Ian

[CarterKraft]

I'm not sure this is a solution for you but it might be for others following you.

https://store.propridehitch.com/lipp...echnology-kit/

[kscarter]

Dan - I'm in the tear-out phase on my 77 Sovereign and looks like I will be needing both a new A/C and heater so this may be a good alternative for both.

Are you still planning on supplying any kind of heat to your holding tanks? Thinking I might need to add some heat pads if I go with a split unit when I reinstall the tanks.

How flexible are the coolant lines? Was thinking a tray could be built on the tongue to allow the unit to slide all the way against the shell while traveling (some sort of cushion between) and then pull out to provide the room needed once set up at the campsite.

Kevin

[TouringDan]

Originally Posted by Iansk

This cat looks to be pushing the 4” minimum clearance a wee bit.

Also, that’s some lift on that trailer. Judging by the cinder block steps it has about 24” of clearance.



Regarding the coiled up line set, I shortened mine so it was a straight run instead of having all the excess coiled up.



Ian

lan

You definitely want the line set as short as possible to get the best performance from the heat pump. My line set is 16 ft long. I believe and am hoping that it will be long enough, but I may need to make it a bit longer. Good for you that you shortened yours up.

Dan

[TouringDan]

Originally Posted by kscarter

Dan - I'm in the tear-out phase on my 77 Sovereign and looks like I will be needing both a new A/C and heater so this may be a good alternative for both.

Are you still planning on supplying any kind of heat to your holding tanks? Thinking I might need to add some heat pads if I go with a split unit when I reinstall the tanks.

How flexible are the coolant lines? Was thinking a tray could be built on the tongue to allow the unit to slide all the way against the shell while traveling (some sort of cushion between) and then pull out to provide the room needed once set up at the campsite.

Kevin

Kevin

We don’t plan on camping in weather that would be cold enough to worry about heating the holding tanks. However if we do find ourselves in that situation we still will have the furnace to,provide heat for us and the holding tanks. Only you can decide if you will need heat pads to warm your holding tanks. It may be better to be safe rather than sorry though.

The refrigerant lines are soft copper so not very flexible. I am not sure what you are gaining by going with a sliding compressor support pad. You are also now requiring more space to install the compressor. Where are you going to mount your propane tank(s)? I do think you are now making support of the compressor much more difficult than it already is. I would not take this route.

Dan

[truckasaurus]

Dan, I've been wrestling with how to install the outdoor unit and propane tanks in a space that's just a bit too small on my trailer and thought the idea might be of use to you. I created a thread to get some feedback as it might be a terrible suggestion but I think it's probably legal, safe and allows unimpeded air flow. https://www.airforums.com/forums/f28...ml#post2369923

[TouringDan]

Originally Posted by truckasaurus

Dan, I've been wrestling with how to install the outdoor unit and propane tanks in a space that's just a bit too small on my trailer and thought the idea might be of use to you. I created a thread to get some feedback as it might be a terrible suggestion but I think it's probably legal, safe and allows unimpeded air flow. https://www.airforums.com/forums/f28...ml#post2369923

The footprint for the propane tanks is about the same as the footprint required for the outdoor unit. It puts the unit in contact with my jack so, as Bubba suggested, I moved my jack forward about 1.25”. This will leave adequate space, in my mind, for a small horizontal 10 Lb propane tank with minimal affect, if any, on the performance of the mini split.

Your concept of locating the skinny long propane tank within the frame cavity seems reasonable but will come with a few other problems I suspect. You know that “new solutions have new problems”.

Dan