RV Mini Split plans (Input welcomed)

[chaostactics]

So I've been doing a bunch of thinking on the subject and I think I want to go for it. I've got about 2 months before I pick up my GD2150RB. I can't plan for everything but I want to plan as much.

At this point theres enough proof of concept of installing these things on RVs and the benefits are so many.
1. Way more efficient than roof top units. (Less than 500w draw for middle of the road units and less so with a high end inverter unit). Gives me more quiet generator use, cheaper utilities, possibility of running solar down the road.
2. Can function as a heat pump (it's recommended to run a in combo with a furnace in the winter to prevent water line freezing.
3. Can function as a dehumidifier.
4. Mid and higher end units have built in smart technology which means not having to install a ridiculously expensive smart thermostat if you want wireless control.
5. Incredibly quiet when compared to rooftop units.

Barriers: losing some inside space in cabinetry, having to figure out where to mount the outside unit, worrying about possible damage from using a residential AC on a mobile unit.

[chaostactics]

QandA
What about the weight?
The inside units for 9000 BTU typically weigh rate around 30 to 40 lb. The outside units weigh somewhere around 80 lb. A class 27 deep cycle battery weighs around 60 lb for reference.

I was already planning on moving my tongue mounted battery to the basement. This means I will lose space in the basement but reduce likelihood of theft of the battery. And of course makes room physically as well as weight wise on the tongue.

How much does it cost?: a decent really decent mini split that should service my travel trailer cost $1,000 or less. And that cost is somewhat defrayed by the efficiency gain monetary wise. Not to mention the non-monetary benefits of a far quieter and way more efficient unit.

Residential mini splits are not meant to run on RVs what about possible damage the unit?
While this is true there are a number of people out there who have shown that they will last years and years if properly taken care of and mounted. And many thousands of miles. One way of significantly improving the likelihood of durability is the availability of flex lines that can be installed between the outside unit for about a foot to foot and a half in length to the refrigerant lines that run to inside. A lot of people bumper mount units. I would tongue Mount this and in theory a tongue Mount unit should be subject to less balance than a bumper Mount unit. Also if you somehow managed to break one of these the cost is relatively low.

Residential mini splits do a good job of keeping a room cool but aren't known for their ability to bring a room down and temperature from hot conditions what about that?:
The solution people have found this is to leave the roof mounted AC in place and then run that when they first get to the campground to cool down the trailer. If you're trying to cool in a hurry then switch over to the mini split. The other option of course is just to turn on your midi split immediately once arriving at the campground and then by the time you're done the rest of your setup it should have had a chance to cool down the trailer a reasonable amount. And again you still have the chance to run a rooftop AC.

What about the power draw on the trailer can it be done on a trailer with a 30 amp service?:
The answer is yes the 9000 13,000 BTU units draw less than 15 amps, especially the inverter units which draw less than a rooftop even with a soft start on the rooftop unit. And the operating amperage has been shown to be around 8 to 10. You can easily find units that run on 110 to 120 volts.

What else do y'all think I should consider? (It does appear that there is an open spot in the breaker panel.)

[chaostactics]

Further QandA.

Shouldn't the inside unit have more clearance around than the area you selected in the cabinetry?

Well yes that is ideal people have shown these to run in this configuration just fine and you can pick up a fair amount of space above below and to the side of the unit if you cut out the cabinetry carefully.




Sources considered for examples are:

https://www.escapeforum.org/forums/f...ofit-8249.html

https://youtu.be/arj2ioF8z9o

https://youtu.be/VcyWW4bB34w

https://youtu.be/Ff5DaVOOn-8

https://youtu.be/arj2ioF8z9o

[MarvinG]

My impression from one I had in a radio station some years ago, experience in the HVAC service world and knowledge of physics doesn’t agree that they will cool more slowly from a hot start than would any other AC. I believe they will do just as well or better for all practical purposes. If I am wrong however, your work around would certainly take care of the problem.

Disclaimer: I don’t have on on my Class A RV but should one of my old rooftop units fail, I will have a good excuse to do what you are contemplating. I am impressed with the concept and see little to no downsides to moving forward.

[hoovers]

So I finally know enough about something on this forum to chime in!!
As an hvac co owner and seasonal 5er camper, last weekend I installed a Senville 115 volt 9000 btu Minisplit in our camper
With the rooftop unit running, we had a choice of being cool or watching tv with the volume up high
I mounted the condenser on the bumper using 1/4 plate steel legs to get it 8” from the camper so it can breathe. 1 of the pictures above showed it too close to the camper, and if it doesn’t breathe it doesn’t work!
I mounted the indoor unit next to the fridge, aiming towards the kitchen and entry door, this machine has a swing function that lets it blow up and down as well as side to side
It takes about 5 minutes of initial run time to start fully cooling, but currently at our campsite in Stuart’s Draft, Va, it’s 91 outside and 65 inside
As posted above, I do use the rooftop when we first get here as we leave the stat on 85 while we are gone
A few fairly important points!….
1) get a 115 volt system, I run ours right from the camp pedestal
2) gravity is your friend for draining condensate
3) if you don’t have the right tools, including vacuum pump, tubing cutters, flare tool, ect, Mr Cool brand has pre charged linesets, just select a pretty close length, if it’s too long, don’t loop it vertically as that will make an oil trap, loop it horizontally!
4) black is hot, white is neutral, red is signal, don’t mix up any of these or the smoke will come out!!
Good luck with your project!
Jim and Stacy Hoover

[MarvinG]

Jim, so indeed they do the initial cool down more slowly than the old, noisy rooftop units? I stand corrected. A small price to pay for the other advantages though I think.

[chaostactics]

@hoovers. Thank you so much for your very detailed response and from someone who has experience in the HVAC industry and who's done the project what a bonus! I really appreciate you taking the time to type all out.

I do have a small concern with it "breathing". I am going to try to center it between the front wall off the TT and the LP tanks. I will probably bias the position a bit towards the back as the front wall is curved and the LP tank covers are flat so the curved wall should be less of an obstruction.

You didn't happen to photo or video document your install did you?

I looked at the cost of the all in one set up vs the cost of a regular unit + buying the vacuum set up and flare tool. I still come out on top buying the tools and I can always sell them to recoup some money. Or if I can find an HVAC guy who moonlights on the weekend.

Could you expand a bit on not cooling vertical vs cooling horizontal? I'm hoping to come up with a set up with a small enough run to not have to coil at all. But if I need to seems like you have a really good tip there but I want to make sure I know what you mean.

I think you mean coil how you'd coil a rope on the ground not coil it in the position say youd hang extension cord in.

Did any of your coolant line run under your RV? If so did you shield it and how? I think I'm going to have a very short run go under the TT to come up through the bottom of the basement/passthrough. It looks like they sell cable chase style cap that should be able to cover it.

Ps thanks for coming out from lurking to help me out

[chaostactics]

@hoover I for for to ask. How did you size your mini-split? The trailer currently has ~13k BTU roof unit on it.

I really really really want to be able to use it as a dehumidifier. Everything seems to be 9k or 13k for the mini split. I want to avoid having it short cycle.

[chaostactics]

This was the unit I was considering if I was gonna go higher than 9K BTU. A SEER of 22.5 should make operation on a solar array down the road within reach.

It's an inverter type.

I noticed somewhere I read about having minimal cooling line lengths but I don't see anything about that in the install instructions on this. It says "cut to any length". I haven't made measurements but I'm thinking it would be in the realm of 10-12' of needed line.

https://www.homedepot.com/p/Hessaire-DIY-22-5-SEER-12-000-BTU-Wi-Fi-1-Ton-Ductless-Mini-Split-Air-Conditioner-and-Heat-Pump-Variable-Speed-Inverter-115V-H12E1/315698888?g_store=1706&source=shoppingads&locale=e n-US&&mtc=SHOPPING-CM-CML-GGL-D26P-026_002_AIR_CIRC_ACC-NA-NA-NA-SMART-2998850-NA-NA-NA-NBR-NA-NA-NEW-PL3_Live&cm_mmc=SHOPPING-CM-CML-GGL-D26P-026_002_AIR_CIRC_ACC-NA-NA-NA-SMART-2998850-NA-NA-NA-NBR-NA-NA-NEW-PL3_Live-71700000094213712-58700007814434221-92700071019454060&gclid=CjwKCAjw2f-VBhAsEiwAO4lNeKT4efEJAQN5myAd7Zpvmateknk6nrXeElJPy weRzxIOJ1xJlNxfmxoCnP8QAvD_BwE&gclsrc=aw.ds

[hoovers]

Hi, tried to send pics, but in the Shenandoah Valley, the cell service motto is “ good luck” pics should be up Monday
I did respond to previous questions, doesn’t show as posted yet
You are correct about 9000 and 13000, my only requirements were 115 volt, short indoor unit profile, and cost
We paid $700 for Senville on Amazon with 15’ lineset and comm wire
Since I needed 21’, I put their stuff on my truck and used my stuff
Fireworks just started, will finish tomorrow

[geordi]

I've got a 40' DP that seems to have blown one of the roof air units - this doesn't amuse me. I'm thinking strongly about going this direction, the only questions have been where to mount the condenser unit and if the condensate line is gravity only. I was thinking to put the condenser on the roof (because why not, there's plenty of room) as long as that drain doesn't have to return to the condenser OR if it is powered. The evaporator SHOULD fit inside the coach above where I have my LED TV mounted - b/c the original cabinet design was a giant tube TV. I removed that, cut the cabinet down to make a small shelf for the devices, and added a vertical board about 6 inches behind the windshield that the TV mounts to. So if that cabinet / shelf I made went away, the entire air handler could mount right above the TV. The only thing I'd have to sort out is my sound bar and that drain line.

[hoovers]

Hey Chaos, I did not run the lineset under the camper, was concerned about thrown up rocks and road debris
I did consider that, and decided if that was the easiest path to run it in 3” pvc, not the easiest way to do it but would protect it
I also decided to put the outdoor unit on the rear bumper for the same reason, doesn’t take too many rocks hitting the fan or worse, the coil, to ruin a fun project!
Your drain can go anywhere, gravity always works! There are wired in Minisplit condensate pumps, but even the biggest one only holds 3 tablespoons, and goes off all the time in the summer, very noisy
It’s really not a tough project, after reading on this forum for 5 yrs, trust me, there are way bigger brains than mine on here!

Oh yeah, forgot a maybe important thing!! Our 5er is in a seasonal site for last 2 yrs, probably gonna move in the spring
When you mount the indoor unit backing plate, there are numerous screw holes, use them and make some more if needed! If you hit a metal stud, follow that line down, and screw the bejesus out of it, last thing you want is the indoor unit to bust off the wall when traveling
I used about 40 1” drywall screws, and when I found a metal stud, maybe 10x 3/4 sheet metal screws, I might bust a tire, but that machine is staying right where I put it!

[hoovers]

Hey Geordie, mini splits also have a ceiling cassette indoor unit, 24”x24”
They make great wheel chocks, and after a bunch of failures because of piss poor design, we flung one with a trebuchet! Didn’t even go 100 yds but very satisfying!!
The high wall heads or the floor consoles are the way to go

[chaostactics]

Some screenshots from YouTube. Grain of salt for their accuracy