Our next rig

[Davydd]

You would then have to have two different dump points and hose attachments and no way to combine a black tank and grey tank as Avanti has stated it is a desired goal. You are not going to get a grey tank behind the back axle with a black tank worth a damn.

[avanti]

One possibility would be a conventional toilet/black tank aft with a dedicated macerator and a separate macerator on a forward gray tank.

[GeorgeRa]

Originally Posted by avanti

One possibility would be a conventional toilet/black tank aft with a dedicated macerator and a separate macerator on a forward gray tank.

If you keep gray water contamination with solids low you could use a submersible, centrifugal magnetically coupled pump in lieu of flexible vane macerator pump – long life and no maintenance. Disadvantage is no self priming if above water level.

[avanti]

Originally Posted by GeorgeRa

Microwave is a little high.

Originally Posted by Davydd

I think George is right. The microwave should not be that high. You have a chance to rectify past vans. The freezer can be lowered especially if you considered a drawer type freezer. Then the more frequently used refrigerator will also be at a more practical height. Then you can install a continuous upper cabinet. The upper cabinet height also is where the curvature of the shell is most in the way. Have you measured to see if a microwave is practical at the upper shelf height?

Thanks for the comments. Helpful.

The issue is that the space under the fridge is pretty ideal for plumbing and other utility stuff: water pump, hot water & air heat exchangers, tempering valve, etc. This position keeps the hot runs to the shower short (saves water) and makes it easy to heat the bathroom. The fridge is shown a bit higher than necessary in the sketch. We wanted a drawer-style freezer, but couldn't find one of the right size. We are going with the Isotherm Cruise 195.

Plenty of depth for the microwave. In fact, it would be a bit wasteful above the fridge. In our current rig we have the electrical panel and electronics above the fridge, with the microwave to the right about the little window behind the driver. Less depth there, but it fits OK. Might end up doing that again, although it is just as high. We are tall people, so it isn't bad for us.

Not committed to anything at this level of detail yet. The upfitter will do a mockup when the van arrives, so there is time.

[avanti]

Just got word for Ford that our Transit (ordered late October 2021) has finally been scheduled for production in early May. If this date holds, which it probably won't, that would mean a delivery to our upfitter in maybe the middle of June.

Small steps...

[avanti]

I have decided on this A/C:


https://undermountac.com/collections...ted-evaporator

It is a ProAir unit integrated by this vendor (kind of like Jim Rixen but for ProAir rather than Espar). It is a very nice ducted setup with variable speed compressor and condenser. 24VDC, too. The condenser will be mounted in the high rear cabinet above the rear doors, with ducts both downward (toward the bed) and also forward. I can't wait to have cool air while also being able to hear myself think.

[booster]

Haven't we heard about problems keeping the condenser clean under the vehicle? Or have they come up with a solution to that?

[Punkinhead]

My upfitter uses the split system and my plan is to use one of these power washer attachments meant for cleaning vehicle undercarriages.

[avanti]

Originally Posted by booster

Haven't we heard about problems keeping the condenser clean under the vehicle? Or have they come up with a solution to that?

Yes, we certainly have heard this, mostly from ARV who was originally, at least, reporting second-hand information from "ambulance companies and others".

https://www.youtube.com/watch?v=eYBjy_58y0g

(My memory was that they eventually tried one themselves, but I can find no current evidence for that, so I may have been wrong.) Their purported issue was "dust clogging". I have never found this to be plausible, since nearly all automotive A/C evaporators are horribly exposed to road dust, and they work fine.

In any event, back when these rumors got started, most or all such systems (including the infamous RoadTrek models) had vertically-mounted evaporators, usually perpendicular to the direction of travel, which is pretty obvious pessimal. This is because the then-available evaporators were designed for the back of truck cabs and did not work properly when mounted horizontally. But, the Pro-air unit I am using works fine horizontally-mounted. I expect this to make a big difference, for aerodynamic reasons. If I am wrong, I will devise a protection-scheme (e.g., electric louvers that close while underway. I am betting it will be just fine, though.

Finally, even if it turns out to require routine maintenance (which I doubt), I would STILL go this route. There are so many advantages, aesthetically, practically, and acoustically, that it would be worth the hassle to me. We'll see...

[booster]

Originally Posted by avanti

Yes, we certainly have heard this, mostly from ARV who was originally, at least, reporting second-hand information from "ambulance companies and others".

(My memory was that they eventually tried one themselves, but I can find no current evidence for that, so I may have been wrong.) Their purported issue was "dust clogging". I have never found this to be plausible, since nearly all automotive A/C evaporators are horribly exposed to road dust, and they work fine.

In any event, back when these rumors got started, most or all such systems (including the infamous RoadTrek models) had vertically-mounted evaporators, usually perpendicular to the direction of travel, which is pretty obvious pessimal. This is because the then-available evaporators were designed for the back of truck cabs and did not work properly when mounted horizontally. But, the Pro-air unit I am using works fine horizontally-mounted. I expect this to make a big difference, for aerodynamic reasons. If I am wrong, I will devise a protection-scheme (e.g., electric louvers that close while underway. I am betting it will be just fine, though.

Finally, even if it turns out to require routine maintenance (which I doubt), I would STILL go this route. There are so many advantages, aesthetically, practically, and acoustically, that it would be worth the hassle to me. We'll see...

Isolating it while driving was my first thought also, and pretty much foolproof except for the mechanical parts of it.


I don't think you can compare a front mounted AC condenser to an underbody, though. The front of the vehicle sees relatively clean pressurized airflow due to speed and unless you are closely following another vehicle on a gravel road, the air is pretty clean compared to underbody air. Underbody is normally a low pressure area relative to the front and sides of the vehicle and tends to be very turbulent in vehicles with lots of stuff under them like our vans. It moves slower and with less force than front air by intention to prevent air pressure lift of either end. It is kind of interesting to see the dust pattern kicked up by vehicles on dirt roads to watch where it goes and winds up after it comes off the wheels. I have seen some that will actually suck some of the dust from the sides to under the body because they have really good low pressure created, probably by a low front air dam.



My 96 Buick spent a lot of time in Texas before I got it and must have seen a lot of dirt roads, as the entire underbody had a coating of what looked like Texas dust on it. Some areas approached 1/8" thick of built up dust. I have never seen that up here in Minnesota.


I do think the if you put the condenser so it is not facing the airflow direction it will help a lot, and even a few airflow directing baffles may be enough to prevent issues, but closing off is probably still a bit better if needed.


Maybe of interest. Our 4 AGMs sit across the body right behind the rear axle. I have a rubber baffle that covers the forward and both sides of them and a solid floor on the battery tray. This leaves only the rear open and that is the lowest pressure area around the batteries due to airflow the vacuum pulled by the rear exit air of the body under the van. They have been in for 5 years or more and are still really quite clean, much cleaner than I expected them to be and they have never been cleaned at all in that time.

[Punkinhead]

When I first heard of undercarriage mounted condensers my reaction was that it would get filthy and rob heat transfer. But with things like this I always ask myself if this is just a theoretical problem or a real one? I tried googling for this "problem" and came up empty. These systems have been out in the wild long enough that we'd probably know about it if it were a real issue. I still plan to go with a split system for all the same reasons avanti listed. I've cleaned the outdoor unit on my house AC every year for over 30 years so if I need to clean the condenser in my van occasionally then so be it.

[Davydd]

Advanced RV has installed split systems in their vans and they install them in their.B-Boxes (Class Cs) now. The Houghton air conditioner we have on the roof is quiet enough for us and not installed over our beds. Of course we haven’t used it in a year of travel and 15,000 miles so it is not a priority anyway for us.

[jrobe]

The Houghton AC is also not much more than $1000 (1/3rd the price) and probably cheaper to install.

[avanti]

Originally Posted by jrobe

The Houghton AC is also not much more than $1000 (1/3rd the price) and probably cheaper to install.

Yes, there are now several rooftop units that are significantly quieter than older options. If they meet your desires, they are obviously vastly cheaper. But that is true of many of the things I am putting in this van. This time around, I have decided to take the advice of another member on this list and do my best to take on the "if you have to ask..." attitude (although it is not really my nature).

We want quiet (not just quieter) and also long run time. Running on ultra-low, I am pretty sure this unit will come closer to these ideals than any other current option. And, we won't have that...thing sticking out on the roof of the van.

[jakegw2]

I think location and air flow under the carriage is key. We also have undercarriage mounted batteries and generator and both items (located behind perpendicular blocking structural members) stay surprisingly clean even in dusty travel conditions. Certainly there are other areas underneath that are a mess after driving in bad conditions, but with some forethought you will probably be fine.

[avanti]

Originally Posted by jakegw2

I think location and air flow under the carriage is key.

Agree. When I did my 4-season upgrade to our current rig, I added large sheets of extruded foam insulation in the tank areas. Most of the undercarriage stays almost pristine. I think the sheets make the airflow much more laminar. There is a reason the bottoms of many modern cars are solid sheets of plastic.

[Boxster1971]

Originally Posted by avanti

. . . .
. . . We want quiet (not just quieter) and also long run time. Running on ultra-low, I am pretty sure this unit will come closer to these ideals than any other current option. And, we won't have that...thing sticking out on the roof of the van.

The Cruise N Comfort units that are popular with Van Lifers use an undermounted compressor and condenser.

https://www.cruisencomfortusa.com/hd-series

However, they are not as powerful as the Pro-Air systems.

[GeorgeRa]

I had limited experience with Truma Saphir AC in Europe, it was very quiet. Somehow this type of AC didn’t reach our shores, perhaps Truma knows why but I don’t know. It is very quiet and it is not very exposed to elements but it is vented through the floor. https://www.truma.com/int/en/product...hir-comfort-rc See this video, amazing 80/20 aluminum framing as well.

https://www.youtube.com/watch?v=jDi5LsMi5Pw

[avanti]

Our Transit has been built and delivered to the dealer. In a few days it will make its way to our upfitter. We are deep into working with them on the detailed design. Been working recently with their EE on specs for the electrical system. This is made more complex because of the need to anticipate the requirements of my automation project. Lots of fun.

2022 Transit HR LWB EXT 1.jpg

2022 Transit HR LWB EXT 3.jpg

2022 Transit HR LWB EXT 4.jpg

2022 Transit HR LWB EXT 5.jpg

[GeorgeRa]

It is indeed a lot of fun, enjoy the process. To compensate for lack of physical prototypes extensive CAD helps a lot. I used CAD to a great extent but I made a few mistakes, fortunately not big enough which I couldn’t overcome.