Lower Bay Mini Split AC size

[TomC]

I know many do not like the look of roof top airs. But-they are the most efficient way to get cold into the bus. We have 3-13,500btu Colemans. Since I don't have dash air (the transmission did not have the PTO for A/C, nor room for the compressor on the engine), I mounted the front roof top towards the front. Have the front half aimed down at the driver's seat and also have a 12v dash fan blowing on me. Have always been comfortable when driving with the roof tops running off the Diesel generator. Roof tops are easy to service, but more noisy. Good Luck, TomC

[digesterman]

Prznbus the four units in my bays are vented through the floor and sealed off from the rest of the bay, the heat has no effect on them.

[PRZNBUS]

Prznbus the four units in my bays are vented through the floor and sealed off from the rest of the bay, the heat has no effect on them.

I was talking about mounting them in the rear engine bay where the factory AC compressor was.

Bruce

[digesterman]

Sorry I see Scott had mentioned the heat in the bays

[Scott & Heather]

Prizn, you know, it's funny though that you mention how that space could be so useful. I've often thought about partitioning it off and insulating it from engine heat. The only issue I think we should try to solve is a way to have the "compartment" partition swing open or removable because when you need to service the engine, you need access on both sides. If you are forced to take your partition apart or remove the minisplit every time you want to change the starter or anything else, that would be drama


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[somewhereinusa]

I got the rear unit operational yesterday and couldn't be happier. Still have some final dressing up to do. It wasn't really all that hot yesterday, but I did get the bedroom down to 65 in a couple of hours. It was cool enough this morning to test the heat, made it toasty in the back. This thing is QUIET, if nothing else is making any noise, when I first start it up, I get a sense of the outside unit more than being able to hear it. When it's running the only thing I can hear is the inside fan, which is very quiet. It blows very cold or hot depending on the setting.
I hooked up my Kil-a-watt, on start up it VERY slowly climbs to 7.3 amps, then falls to 2 to 3. I just checked and while on high heat it was at 10 for a few seconds then fell again.

Condenser unit mounted in original condenser space. I will put the original screen and trim back on. The frame is the original, that never seemed to have been damaged, I also mounted a second rock guard in front. (the white one)





There was no way I could get the larger line routed around all of the corners, I tried, without kinking. The smaller of the rubber refrigerant lines from the original factory air was the right size, so I had new flair ends put on it and it worked perfectly, I'm hoping this will also alleviate the problems some have had with line breakage, the 1/4 inch line is much more forgiving. I then insulated the rubber line. When I pulled a vacuum, I was a bit surprised to find that it stayed exactly all night, I figured it would change some because of the temperature change. The sun was shining on it when I did it and it was cool the next morning.

The condensate tray on the evaporator had provisions for a drain at either end so I put a T in and used them both. I painted the inside unit so it wasn't that ugly white, I may do some sort of enclosure to hide it later.



I'm a little concerned about how the feet are fastened to the body, just two spot welds. I also made an upper mount to help control movement at the top, hoping to reduce stress on the bottom feet. I made the bottom rubber mounts more to keep from crushing the feet when I bolted it down than anything else.







Only time will tell if this was really a good installation, but right now I am extremely pleased.

Dick

[Darkspeed]

Hi Dick, looks good!

You said you used one of the old rubber lines? Was the old system R12? 134A?

Not to freak you out but a lot of the rubber R12/134A lines wont survive R-410A chemical / higher pressure.

You may want to check the part number on the rubber hose and find out.

R-410A can have a high side pressure of 410+ psi and a low side 130+

R-12 is less than half that.

R-410A hoses have a burst rate of 4000psi and a operational rate of 800psi.

The good news is you are using a R12? high pressure side hose as the low pressure side hose of an R-410A system so it may last longer than expected.

[luvrbus]

How do guys handle the water those mini splits are so efficient removing the humidity,the complaint I hear from 2 friends that have those is the water problem dripping or blowing from the evaporator and yes they have the drains hooked up going to the bottom of the bus 

Going to be interesting how good the unit in the photo works picking up 140 degree heat from blacktop mount that low 

[Darkspeed]

How do guys handle the water those mini splits are so efficient removing the humidity,the complaint I hear from 2 friends that have those is the water problem dripping or blowing from the evaporator and yes they have the drains hooked up going to the bottom of the bus  

Going to be interesting how good the unit in the photo works picking up 140 degree heat from blacktop mount that low  

luvrbus, I think the reason people are blowing condensate is they are not mounting the unit on a flat wall. If you tilt them forward like the curvature of a buss shell then they dont drain properly and water pools in the condensate catch. Also im sure they have a convoluted path for the drain line causing some restriction.

[luvrbus]

They have no problems with condensation when parked only when traveling and running the units

[somewhereinusa]

You said you used one of the old rubber lines? Was the old system R12? 134A?

Not to freak you out but a lot of the rubber R12/134A lines wont survive R-410A chemical / higher pressure.

You may want to check the part number on the rubber hose and find out.

R-410A can have a high side pressure of 410+ psi and a low side 130+

R-12 is less than half that.

R-410A hoses have a burst rate of 4000psi and a operational rate of 800psi.

I'm pretty hard to freak out, good information, if it fails, I'll know where to start looking.

[Darkspeed]

I know R-410A is supposed to be non toxic but i dont know what effect a leak would have on a bus of sleeping campers? Just something to think about..

[Scott & Heather]

I'm glad someone else is experimenting with this. Do tell us how it works longer term. We have already made up our minds to install mini splits in our new bus. the only difference is we won't use the interior units. They are huge and ugly. I will buy the ducted mini split units and duct them throughout the coach. Still quiet, just better air dispersion and no massive inside unit.


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[luvrbus]

I been reading about these units seems like condensation can be a problem,the better units have shut offs for high levels of condensation and they sell pumps to compensate for it.

I have a pump for a mini split I tried to giveaway here , as I had no idea what it was for after reading I see the pump is a kit wired to the Mitsubishi or other units.

Lol when you live in AZ the AC is a very important part of your everyday life I am sure if anybody can work it out you guys can

[Darkspeed]

I have used mini splits in mobile applications and I have never had an issue with water / condensation. I always upsize the drain tube to account for bends in the run. The most important thing is to elbow the end of the drain tube and aim it towards the back of the bus / truck so it functions like an eductor when the vehicle is in motion. If you just blunt cut it at the bottom of the vehicle it will create eddies of air in the end of the tube which can keep it from draining or forbid aim it toward the front of the bus which created a positive pressure in the drain tube causing water to blow out of the head unit when in motion..