Improving 2014 Parkliner air conditioner

[trasko]

I acquired a 2014 Parkliner last November through a member of this site. It's been a great trailer thus far and was well cared for. However, one thing that has been a disappointment is the performance of the A/C. I had done my research ahead of time and had seen other folks complain of this (including the PO) so it wasn't a surprise. Despite that I held out hope it would be "good enough." Enter a cross-country trip and a heat-wave and it was very far from "good enough."

In the shade and 95F ambient it would get the trailer down to about 90F. It was a low-humidity 90F so it was a noticeable improvement over outside, however entirely insufficient to be comfortable. One of the main reasons we got a trailer is that we moved to the Southeast from a place with great weather and low humidity. We used to backpack, camp and generally enjoy the outdoors year round. We still do that about 2/3rds of the year now but the summer is when school is out. I can tolerate the heat fine -- I grew up here. But going out in it for enjoyment is another matter altogether!

I'm about halfway through with this project. I figured I'd write it up here because I haven't seen anyone else do what I am going to do. I'm going to break it up into sections. I'm all for feedback but if you've got any super-great ideas send them quick because I've already gone to town with a jigsaw and pry bar!

First section: what I'm starting with.


edit: I'm trying to post replies but it says it will be posted once a moderator approves it...

[trasko]

My Parkliner came with what I believe all of the first few years worth of them came with: a 5000 BTU window unit made by Frigidaire.

Model LRA050XT7. Fridigaire website says it is discontinued. (https://www.frigidaire.com/Owner-Cen...port/LRA050XT7) but I have it them for sale on Amazon currently for $165. It may be available by other manufacturers. It is distinct compared to most modern window A/C units in that it uses manual dial controls -- almost everything is electronic these days. It is also the SMALLEST window A/C I have found in a few hours of research. Even compared to other 5000 BTU models it is consistently smaller in at least one dimension.

It is installed in the port side front under the "side dinette" seat. It faces towards starboard blowing pretty much straight at the door. The blower portion is about 16" off the floor -- so pretty darn low. It's an efficient use of space which I appreciate. It is slightly angled towards the center of the living space which helps keep the control knobs away from your legs and looks nice aesthetically.

In terms of its installation: it's in there pretty tight. There is no extra room and it is fussy to get it out. There is a wooden block on the front you screw into place which prevents the unit from coming out which is the only direction it can possibly move. Also of note on the picture of the A/C you'll see a small tab on the right side of the cool-air intake which is what you pull to remove the mesh filter. You cannot open that at all when the unit is installed. Even if you pull the A/C half-way out you still cannot remove the filter. Not the end of the world but... not great either. I'll expound more about the details of the install in the next post where I go into the research I did -- both online and in person.

In regards to its operation, the unit always fired up immediately and began to cool quickly. It was remarkably quiet outside of the trailer. You can hear it but if there is any other ambient noise going on it is hard to notice. Inside the noise is moderate. Enough you can't whisper to another person and expect to be heard but you don't need to shout, either. Watching a show on tiny laptop speakers is not a problem.

One thing that is confounding in this whole endeavor is if you sat down right in front of the unit (like my kid did!) it blew cold. Real cold! If I went to the exhaust vent on the outside it was blowing pretty darn hot. So it was "working" in that it was pushing some cold air into the cabin and pushing hot air out of the vent. But at the same time I knew that it wasn't getting the temperatures down much at all even when given many hours to do it.

So in conclusion of where I started: I liked the A/C in many respects. It's size/weight, the low noise and its location where it doesn't create more drag on the roof or impinge upon headspace. The only thing I didn't like is that it didn't actually cool down the trailer!


Pics:
- exhaust vent circled in yellow
- close-up of from of A/C unit
- general idea of where A/C is in relation to rest of camper. This is from our first "shakedown" camp

Next: research/planning how to improve cooling.

[Casita Greg]

I don't see any air conditioner on your trailer. All I see is a fan with a rain cover.
A fan isn't really going to lower your trailer's temperature, it just moves the hot air around.

[andersok1]

I'm guessing your AC is like mine (also a Parkliner, 2013 I believe): a regular window unit housed under the seat where it stews in its own heat production while trying to push its exhaust the 4 inches to the vent in the fiberglass. I'll be watching your progress with interest!

[trasko]

My Parkliner came with what I believe all of the first few years worth of them came with: a 5000 BTU window unit made by Frigidaire.

Model LRA050XT7. Fridigaire website says it is discontinued but I see it for sale on Amazon currently for $165. It may be available by other manufacturers. It is distinct compared to most modern window A/C units in that it uses manual dial controls -- almost everything is electronic these days. It is also the SMALLEST window A/C I have found in a few hours of research. Even compared to other 5000 BTU models it is consistently smaller in at least one dimension. More on that later.

It is installed in the port side front under the "side dinette" seat. It faces towards starboard blowing pretty much straight at the door. The blower portion is about 16" off the floor -- so pretty darn low. It's an efficient use of space which I appreciate. It is slightly angled towards the center of the living space which helps keep the control knobs away from your legs and looks nice aesthetically.

In terms of its installation: it's in there pretty tight. There is no extra room and it is fussy to get it out. There is a wooden block on the front you screw into place which prevents the unit from coming out which is the only direction it can possibly move. Also of note on the picture of the A/C you'll see a small tab on the right side of the cool-air intake which is what you pull to remove the mesh filter. You cannot open that at all when the unit is installed. Even if you pull the A/C half-way out you still cannot remove the filter. Not the end of the world but... not great either. I'll expound more about the details of the install in the next post where I go into the research I did -- both online and in person.

In regards to its operation, the unit always fired up immediately and began to cool quickly. It was remarkably quiet outside of the trailer. You can hear it but if there is any other ambient noise going on it is hard to notice. Inside the noise is moderate. Enough you can't whisper to another person and expect to be heard but you don't need to shout, either. Watching a show on tiny laptop speakers is not a problem.

One thing that is confounding in this whole endeavor is if you sat down right in front of the unit (like my kid did!) it blew cold. Real cold! If I went to the exhaust vent on the outside it was blowing pretty darn hot. So it was "working" in that it was pushing some cold air into the cabin and pushing hot air out of the vent. But at the same time I knew that it wasn't getting the temperatures down much at all even when given many hours to do it.

So in conclusion of where I started: I liked the A/C in many respects. It's size/weight, the low noise and its location where it doesn't create more drag on the roof or impinge upon headspace. The only thing I didn't like is that it didn't actually cool down the trailer!

pics:
- close up A/C
- exhaust vent on port side
- general idea of location of ACU (A/C unit) in the mess of our first shakedown trip w/ the trailer

[trasko]

[I figured out why my posts were requiring moderator approval: one of my attachments was too large; if you are a moderator feel free to delete those pending posts I made.

My Parkliner came with what I believe all of the first few years worth of them came with: a 5000 BTU window unit made by Frigidaire.

Model LRA050XT7. Fridigaire website says it is discontinued. but I have it them for sale on Amazon currently for $165. It may be available by other manufacturers. It is distinct compared to most modern window A/C units in that it uses manual dial controls -- almost everything is electronic these days. It is also the SMALLEST window A/C I have found in a few hours of research. Even compared to other 5000 BTU models it is consistently smaller in at least one dimension.

It is installed in the port side front under the "side dinette" seat. It faces towards starboard blowing pretty much straight at the door. The blower portion is about 16" off the floor -- so pretty darn low. It's an efficient use of space which I appreciate. It is slightly angled towards the center of the living space which helps keep the control knobs away from your legs and looks nice aesthetically.

In terms of its installation: it's in there pretty tight. There is no extra room and it is fussy to get it out. There is a wooden block on the front you screw into place which prevents the unit from coming out which is the only direction it can possibly move. Also of note on the picture of the A/C you'll see a small tab on the right side of the cool-air intake which is what you pull to remove the mesh filter. You cannot open that at all when the unit is installed. Even if you pull the A/C half-way out you still cannot remove the filter. Not the end of the world but... not great either. I'll expound more about the details of the install in the next post where I go into the research I did -- both online and in person.

In regards to its operation, the unit always fired up immediately and began to cool quickly. It was remarkably quiet outside of the trailer. You can hear it but if there is any other ambient noise going on it is hard to notice. Inside the noise is moderate. Enough you can't whisper to another person and expect to be heard but you don't need to shout, either. Watching a show on tiny laptop speakers is not a problem.

One thing that is confounding in this whole endeavor is if you sat down right in front of the unit (like my kid did!) it blew cold. Real cold! If I went to the exhaust vent on the outside it was blowing pretty darn hot. So it was "working" in that it was pushing some cold air into the cabin and pushing hot air out of the vent. But at the same time I knew that it wasn't getting the temperatures down much at all even when given many hours to do it.

So in conclusion of where I started: I liked the A/C in many respects. It's size/weight, the low noise and its location where it doesn't create more drag on the roof or impinge upon headspace. The only thing I didn't like is that it didn't actually cool down the trailer!

pics:
- close-up of the A/C unit (ACU)
- external exhaust vent circled in yellow
- general idea of where the ACU is located; this is from our messy first shake-down trip with the trailer.

[trasko]

My Parkliner came with what I believe all of the first few years worth of them came with: a 5000 BTU window unit made by Frigidaire.

Model LRA050XT7. Fridigaire website says it is discontinued but I see it for sale on Amazon currently for $165. It may be available by other manufacturers. It is distinct compared to most modern window A/C units in that it uses manual dial controls -- almost everything is electronic these days. It is also the SMALLEST window A/C I have found in a few hours of research. Even compared to other 5000 BTU models it is consistently smaller in at least one dimension.

It is installed in the port side front under the "side dinette" seat. It faces towards starboard blowing pretty much straight at the door. The blower portion is about 16" off the floor -- so pretty darn low. It's an efficient use of space which I appreciate. It is slightly angled towards the center of the living space which helps keep the control knobs away from your legs and looks nice aesthetically.

In terms of its installation: it's in there pretty tight. There is no extra room and it is fussy to get it out. There is a wooden block on the front you screw into place which prevents the unit from coming out which is the only direction it can possibly move. Also of note on the picture of the A/C you'll see a small tab on the right side of the cool-air intake which is what you pull to remove the mesh filter. You cannot open that at all when the unit is installed. Even if you pull the A/C half-way out you still cannot remove the filter. Not the end of the world but... not great either. I'll expound more about the details of the install in the next post where I go into the research I did -- both online and in person.

In regards to its operation, the unit always fired up immediately and began to cool quickly. It was remarkably quiet outside of the trailer. You can hear it but if there is any other ambient noise going on it is hard to notice. Inside the noise is moderate. Enough you can't whisper to another person and expect to be heard but you don't need to shout, either. Watching a show on tiny laptop speakers is not a problem.

One thing that is confounding in this whole endeavor is if you sat down right in front of the unit (like my kid did!) it blew cold. Real cold! If I went to the exhaust vent on the outside it was blowing pretty darn hot. So it was "working" in that it was pushing some cold air into the cabin and pushing hot air out of the vent. But at the same time I knew that it wasn't getting the temperatures down much at all even when given many hours to do it.


So in conclusion of where I started: I liked the A/C in many respects. It's size/weight, the low noise and its location where it doesn't create more drag on the roof or impinge upon headspace. The only problem is that it doesn't actually cool down the trailer!

close-up of the A/C unit (ACU)


external exhaust vent circled in yellow


general idea of where the ACU is located; this is from our messy first shake-down trip with the trailer.

[trasko]

I got some numbers on temperatures. At 82F ambient, the AC can get the trailer to 75F at the countertop level. If you measure the exhaust temp it is around 120-124F. The cold output at the ACU is between 48-50F.

At this point the ACU seems to work fine. It blows cold. It vents hot. I decided to dig into the trailer some to figure out if something was causing it to fail to cool. I'm not the first to do it! Doing a search for "parkliner air conditioner" nets you a few valuable threads both here and elsewhere. Specifically see the one here by "Huck" and "homesteading" dot com. I cannot link them as it won't let me post here for some reason. I'll try to link one on this site here.

I had several thoughts about what was going on. I'll list my theories below and what I learned.

Theory 1: Floor location prevents full cooling of trailer
Theory 2: Poor exhaust vent performance
Theory 3: Overly restrictive exhaust fresh air supply
Theory 4: Poor separation between hot/cold sides of ACU
Theory 5: Undersized ACU for application


Theory 1: floor location

This makes intuitive sense that it should not be great for performance. Even if a typical air-conditioning system doesn't blow from up high generally the return will be high on a wall or ceiling such that it is taking in warmer air and replacing it with colder air in a cycle. In the Parkliner ACU's design it takes air from down low and spits it out down low. And pointing laterally right at the door!


Using an infrared thermometer I verified that there is a distinct temperature gradient. See the graph below. It shows pretty clearly that 1) there a big difference between the floor and ceiling when the A/C is running alone and 2) when you add a fan to mix the air around.



Theory 2: Poor exhaust vent performance
The aluminum grill over the holes cut in the fiberglass shell seemed to me to be quite restrictive. Then once I dug into how the "enclosure" was constructed I felt more and more like it was inoptimal. Consider this: if you took the exhaust pipe from a car and then stuck it into a box and then cut a hole in the box on the opposite side: would it work? Yeah, sort of. Hot exhaust gasses would surely escape from the hole you cut but not before swirling, slowing down and heating the box to the same temperature as all the exhaust gasses. And that assumes the box has no leaks! I think the same thing is happening in the ACU enclosure. The enclosure warms up quite a bit and is not air tight. The PO did wrap the inside walls with reflectix which probably helps to some degree. You can still measure a distinct heat differences. Most surfaces in the trailer are mid 70s and the fiberglass of the enclosure at the rear exhaust area are ~100F when it's running. That heat will radiate into the trailer. How much does it matter? I dunno. It's a relatively small area and typically the top is covered by a thick seat cushion which would be a good insulator. Hopefully some pictures make all this clearer.

I measured exhaust temperatures when the ACU was sitting on workbench in the open vs. the exhaust temperatures I read from the trailer grill. They were identical. Aside from the radiated heat from the enclosure I don't think the exhaust vent was restricting performance of the ACU.



Theory 3: Overly restrictive exhaust fresh air supply
See pictures. This is rather complex and I don't want to write it all up. The short version is the ACU needs fresh air to blow over the hot coils in the back to remove heat. The enclosure has very little space for this fresh air to flow. Pretty much no air can get to the left side, very little to the top and the right side has fresh air access via 6 holes cut into the enclosure. The PO did some rough cuts to the plywood to allow some air to the left. There ARE fresh air holes in the bulkhead below the ACU. You can see them in the pictures with the wires/plumbing in it.

In addition to perhaps not having enough fresh air to cool the condenser if fresh air intake is restricted it would mean the fan was creating negative pressure and sucking in outside/ambient air into the trailer. I think both of these ideas are reasonable but I couldn't think of any way to test them so I just moved on.

edit: I measured the fin area of the original ACU and the new one as well as the openings in the fiberglass. The numbers are: Orig ACU: 130 in^2; 8000BTU ACU: 150 in^2; 2 holes each 42 in^2






Theory 4: Poor separation between hot/cold sides of ACU
In a regular window-unit the "hot" and "cold" sides are separate by the window clamping down on the unit and little accordion separators. This installation doesn't have that. I think it simply relies on the tight squeeze of an installation to keep them separate. I didn't bother testing this and I regret that. I should have worked harder to create a sealed separation to see if it would have improved performance. As it is I don't know the answer. My gut tells me each side is "separated" as much as if you cracked a window in a room an inch. There is definitely a difference but there is also definitely a lot of waste.

I wish I had some pictures to share here but I don't.

Theory 5: Undersized ACU
Perhaps everything is designed/implemented acceptably well and a 5000BTU unit is simply not enough to handle the load. A poorly-insulated, sun-exposed, all-sides touching the outdoors little egg is very different from a room with a single outside wall in a well-insulated house.

Unexplored idea: Leaking door seal
I realized when writing all this up that one thing I had not considered was the door seal. The ACU points directly at the door. And if the seals aren't great there you could imagine cold air constantly leaking out through them into the less dense, hotter air outside. I'll see if I can figure out a way to test that in the future.


What do I think the issue is? All of them to some degree or another. I wish I had spent some time sealing things better before tearing it all apart but here we are. If anyone else has a Parkliner and wants to chat I'd be happy to give you the details of what I would have tried knowing what I know now.

Next up: A short aside about a roof A/C

[trasko]

At some point I got it in my head that normal RVs use roof A/Cs and if I couldn't get the little window ACU to work right then I should just bite the bullet and do it right. I got a Dometic Penguin II and interior distribution box. A little less than $1300. Oof.

I hadn't actually measured anything out, though. Oops. Ends up on the roof of my year of Parkliner there are two existing openings. A nice Maxxair fan in the back (which we love) and midships is a roof "escape hatch."

The fan is the standard 14"x14" hole which the roof A/C needs. The escape hatch is 21"x21". So for a minimum of fuss it looks like I would be replacing the fan. Ends up if you place the A/C in that location it will extend out to the exact vertical edge of the rear of the trailer. Unfortunately for this install, the last 6-8" of roofline back there slopes downward. Won't work.

I knew newer model year Parkliners used roof A/Cs so I dug around a bit. Looks like they put the A/C at the midship location and left the Maxxair at the rear. That's what I would have done had I felt like trying to remedy the over-sized hole.

Still later on I read a couple of places that the owner of Parkliner told people that the roof on older models was not built to support a roof A/C.

At this point I realized that whether I opted to try and fit a larger BTU unit in the existing spot or go with a roof unit there was no need to preserve the existing A/C compartment in it's current form. I could feel free to hack into it and know that no matter what I wasn't going to go back to the 5000btu unit that was there before.

I still have the Penguin sitting in the box in my garage but I expect I'll be returning it soon. One way or the other I can make the new 8000BTU unit fit.

[jwcolby123]

I bought my '95 Scamp back around 2014 with the AC already in it. Not sure if they are all the same but my AC is down low (knee high) to the left as you come in the door, underneath a closet. It works but not well. First of all it is undersized I believe. AFAICT it is a 5k BTU and a 19' RV requires more.

I don't really use my RV except to "pretend camp" with my daughter, where we go somewhere for the day and hang out in the RV. The Hungry Mother thing is the only real multi-day we have done (twice) and it was during the winter so no AC required.

With the current 95 degree days in an area with no shade over the RV, my 5K BTU AC is enough to cool down just the rear table area to a quite comfortable temp as long as I have a small fan to pull the air from the area in front of the AC and push it up and back to the table area. The temp back at the table is in the low 70s.

Because I don't have any campgrounds convenient to me, I bought a Wen 56235i 1900 watt gene, and my daughter Allie and I can now go down to the local airport (for example) and hang out with the gene running and have AC.

My little Wen gene purrs like a kitten, audible but not loud, and the AC only pulls about 650 watts according to a Kill-o-watt. My gene will run for about 6 hours on a gallon of gas (the tank size) running my 5k BTU AC full blast, my absorption fridge and my battery charger. It will even drive my little 800w microwave but it wants to die (on eco mode) unless I turn off the AC while I use it. I have gone searching for full shade which really helps the AC handle the heat load.

I am willing to bet that if I simply replaced the AC with an 8K BTU unit, it would much better cool the entire RV, although also reduce my gene run time. Although a more modern AC with a better EER rating might mitigate the size increase. It would probably help if I also mounted a small fan in the exhaust area to actively pull the hot air out the top set of louvers.

So that is my AC story. It works but just barely. If I used it more, I'd go with a 10K mini-split.

[trasko]

Thanks for the note. Sounds like in the Scamp the 5k BTU unit is working sufficiently well. That makes me continue to think I might have gotten acceptable performance without replacing the AC. Fixing the venting, patching leaks, etc.

[starsea]

One of the main problems is the directional cool air vent has a crappy roller design. It tends to blow the cool air to the refrigerator and door. I made this mod to mine and it cools much better now. I took a floor deflector from Lowe's and put some Velcro on it and the ac unit. At first I got glued the two halves together but it came apart while camping so it has gorilla tape on it now. I plan on using a better glue so it won't look tacky. I used another deflector inside of the main one to prevent condensation. On a real hot day I also have a small fan that will help move the air to the back. The magic fan also helps. Does great during the South Carolina summers.

[Steve Carlson]

I used to have a Lite House with a window AC under the seat like that. It worked okay but only if I opened up the outside louvered cover (which was hinged), otherwise it just made a lot of noise to little effect. I would suggest a muffin fan or similar to move the hot air out of the enclosure through the louvers.

[trasko]

@starsea: Thanks for the tip. The deflector is a clever solution. I'll probably continue to use my little fan to spread the air around but I'll keep that in the back of my mind as an alternative which takes up less floor space.

@Steve: I think you're right. The original AC in the Parkliner has 130 in^2 of area it blows air over. The pair of holes in the side of the trailer add up to 84 in^2. They also have metal mesh over them, an aluminum metal grate and to top it off there was really no ducting/direction to the exhaust air. I think it was doing a very poor job of vacating all that heat.

My plan involves a much larger grate (18x8") which should flow a lot better. I was planning try and make a tight duct but that simply isn't feasible with the room I have left nor the access I have. I'm going to have to build everything "in-place" because I have to slide all the pieces in together in order for them to fit.

[Eddie Longest]

I never did finish my project of putting an A/C in a Scamp closet. I installed a cargo door in the side of the trailer closet so there would be no restriction when in use. You could use a refrigerator vent and remove the door when in use. Just my opinion but I think an 8K BTU house A/C is the minimum size for a fiberglass RV. The Parkliner has a lot of interior volume for its length. YMMV.
Eddie

[trasko]

See attached pictures. My plan is to put a slightly larger ACU into the original spot.

Original ACU: 5000BTU; 12" high, 16" wide; 15" deep (set at slight angle)
New ACU: 8000BTU; 12.75" high; 18.5" wide; 15" deep

To fit the new ACU I had to do several things:
- chop out the entirety of the bottom of the fiberglass "cabinet" so that I could slip it over the ACU from above.
- set the ACU straight in instead of at an angle
- lower the rear 8" of where the ACU is because that part is ~3/4" taller than the original ACU. I accomplishd this by cutting out the plywood in that area and then re-mounting a larger piece of plywood underneath where the previous bit was. This also preserves the slight rearward tilt necessary for condensate drainage.
- drill new "vent" holes in the FG cabinet for recovery air and seal some of the existing ones as they are too far forward.

I am also enlarging the vent from 2 small 7"x6" openings to a single larger 18"x8" opening with a freer-flowing grate. This is a risk but if any water/weather gets in it will be going into an area that is waterproof and drains (the A/C condensate drains here as well). My fingers are crossed on this one.

The airflow for the whole thing is qustionable. The "recovery" (fresh) air that the exhaust fan needs to blow out is limited by all the tight spaces. This is my #1 concern and I'm not sure how to improve it. Ugh.

I'll be using something to seal the FG cabinet to the wall/floor to keep air from mixing. And I'll also have to seal the 3 "zones" of the ACU from each other (exhaust, fresh/recovery air and the "cold" side). (see last picture)

I am feeling less confident with this solution due to the restricted recovery air but for now I am proceeding. I won't have all the parts available until Sunday/Monday and then I'll get it all done.

Also to do: Put the 120V AC outlet somewhere. Room is so tight now there is no obvious place. I'll work on that and figuring out a way to anchor the ACU between now and the weekend while I wait on the rest of the parts.

[trasko]

After laying everything out and looking at the last remaining issues I've found that it seems like the "recovery" air (fresh air for the exhaust fan to blow out) is lacking. I decided to dig deeper and get some numbers.

I've found some info for home HVAC which suggests the "return grill" should be sized at 200 in^2 per 1 ton of cooling. The original ACU is 5000btu (5/12's of a ton) and new unit is 8000btu (2/3rds ton). That would require 83 in^2 and 133 in^2 respectively.

When you look at the bulkhead of the Parkliner where the fresh air is being pulled from under the trailer it amounts to 6 holes of diameter 3.25" (~50 in^2). That air would have to follow a rather narrow path and go through more holes drilled into the side of the FG cabinet the ACU is housed within. Those holes addd up to about 43 in^2 and only expose the right side of the ACU. The top and left sides really don't have access to fresh air.

Conclusion: there is a serious shortfall of fresh air available. Additionally I have only made it worse by up-sizing the ACU.

I only see two options: 1) make more square inches of vents (aka cut into the trailer more) or; 2) find a way to simply hang the butt of the ACU out of the trailer (e.g. mount it on slides and cut a large opening in the side of the trailer which is hinged).

I'll keep thinking on it. Suggestions welcome.

[daleeb]

Interesting conversation..relevant to any rv with an ac installed in a compartment box. In our case the box is a bit higher but still in a tight space. What we have found to help to some degree is to actually remove the exhaust cover during operation. Our camper(Vymeron) has an actual duct that runs from the right side of the enclosure to a vent outside. This is our fresh air in and is very important as you have discovered. I think your assessment of the 3 causes combined tells you why these things don't do a good job of cooling. I think you're chasing your tail a bit if you try to isolate your pink and yellow zones as they mix inside the steel ac case anyway. You would do better to install a duct directly to the outside to allow for fresh air in.

Since your roof is not an option another route is to go with a portable unit. Not familiar with all the workings of the Parkliner but the small closet area to the left of the bathroom? We used a portable very successfully in our Casita before the Vymeron. I think the ac in a box probably looks better (look at how Snoozy does theirs) than one hanging out but as I see it they just don't work as well and probably never will.

[daleeb]

The more I ponder on this(dangerous I know).....After reading some more on this and other forums about ac in a box the only true way to fix it is to have the box external as the ac manufacturer intended. It would take some engineering but I think I would start looking at an ac unit mounted to a sliding tray and an exterior cargo door that would open and allow the unit to slide out during operation. The interior box could be cut away to leave appropriate legs for bench support but no actual box, thus not restricting cold air flow.

[trasko]

Originally Posted by daleeb

What we have found to help to some degree is to actually remove the exhaust cover during operation.

I appreciate you contributing. I am planning to cut more holes to increase ventilation. Both the exhaust and the fresh air coming in. I intend to double the square inches.

Regarding the "exhaust cover" you mentinoed: I think you're right. In my research on soffit vents I found they all have a "Net Free Area" (NFA) rating. This is the number used in calculating how much air a certain vent will pass. In the case of the existing type of slit aluminum grill w/ wire mesh behind it the number I kept seeing was 44% of the external dimensions of the vent. For example: a 10"x10" vent (100in^2) would have a hole slightly smaller than 10"x10" and with the mesh + vent the NFA is actually 44in^2.

I mention this because I intend to leave the option open to myself to later make the grills (intake and exhaust) be "openable." I am using rivnuts to install the grills for now. In the future I may modify them to be hinged or I might just zip out the screws w/ a screw-gun when settling down for a few days.

The effect of removing the cover should amount to roughly doubling of the amount of air it will flow. So removing the cover is definitely useful if you're limited by the venting.



Per my calculations a few posts up the original A/C should have had ~83in^2 and the new A/C (8000btu) should have 133in^2 of venting. Is that measuring the grill or is it NFA? I'm not sure. Where I got the measurement was the sizing of return grates on home HVAC systems. So it probably isn't exactly right but close enough for me. I'm going to say it's vent area (not NFA).

My Parkliner has about 84in^2 of exhaust and 45in^2 of venting from the factory. I'm hoping to cut enough holes to get those numbers to 120+in^2 for both intake and exhaust. And on top of that I should be able to increase ventilation another 50% on top of that by removing some of the vents entirely while in use.