Scamp, Side Air Conditioning

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When I purchased my Scamp 16, it had air conditioning, or so I thought.

What the previous owner had done was to install an ordinary window unit it the closet by the door.

What he failed to note was that the unit he bought drew outside air in from its sides and blew the air through the condenser to the outside. The fiberglass closet sides were so close to the air conditioner's sides that they completely blocked the airflow, starving the A/C from being able to obtain recirulation air.

I solved the problem by cutting the top out of the A/C case and creating a baffle between the top of the case and the intake and exhaust sections of the side vent louvers. This seemed to work fine, even in Florida in August.

I can attach pictures once I remember to borrow the digital camera from work, but let me know if you want to see it.

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Hi Steve
I would like to see it.I got a few ideas kicking around that I would like to try.:wave

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Steve,

If you have the opportunity to include photos of your modification I am extremely interested. My Scamp 16 that is under complete restoration had a similar owner installed household A/C. I have pondered the air movement situation and now that I'm reinstalling the cabinetry your topic is timely.

In my trailer they had opened the side with RV screen covers exposing an area approximately 1/3 larger than the A/C profile. This seemed excessive but with your insight may have been necessary. They also had not run a condensate drain line down and out of the bottom of trailer which allowed the water to fill the closet floor area and rot the OSB beneath the closet and more importantly that vertical piece that attaches the body shell to frame by the door step. Thanks for your input, Fx.

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The following pictures explain how I re-installed the side AC unit.

1. Line drawing of AC, with the bottom line being the floor. A wood base brought the unit high enough to match the opening the previous owner had cut, and transferred the entire weight of the unit to the floor.

2. The base was comprised of three boards which were secured together with wood glue and drywall screws. I used 4 shelf brackets to hold it to the OSB floor and create longitudinal rigidity. I drilled a hole in the AC base and epoxied a brass fitting, to which I attached a water drain hose, which can be seen in the photo.

3. Plumbing strap with a turnbuckle secured the AC unit to the base and the intake/exhaust baffle to the top of the AC unit. Using a metal cutting blade with my jigsaw, I cut a large hole in the metal case of the AC unit so the outside air could be drawn into the unit from the top instead of the sides. The baffle separated this outside intake air from the heated exhaust air.

4. A loose fitting board with a carpet for a seal covers the intake area.

5. The AC unit from the living area.

6. The outside vents. I realize the intake is far smaller than the exhaust, but I worked with what I found, and the result seems to work very well.

<img src=http://www.fiberglassrv.com/board/uploads/3e5d7d62d566bAC.jpg/> <img src=http://www.fiberglassrv.com/board/uploads/3e5d7e3f45c67AC Support.JPG/> <img src=http://www.fiberglassrv.com/board/uploads/3e5d7ec71d189AC Top Inside.JPG/> <img src=http://www.fiberglassrv.com/board/uploads/3e5d7f19106c1AC Top.JPG/> <img src=http://www.fiberglassrv.com/board/uploads/3e5d7f87f141fAC Inside View.JPG/> <img src=http://www.fiberglassrv.com/board/uploads/3e5d7fcc4f549AC Side View.JPG/>

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Hi Steve
I like the way you have done that.I have seen photos of that done in some 13ft Bolers.
Thanks
Ches

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Steve,
Thanks for the info on AC installation. I used your design and installed a 5200BTU AC that I got on sale at Sears for $88. I ran it yesterday when it was 86 degrees outside and cooled the Scamp down to 73 before shutting it off (it was still cooling). I have been trying to figure out how to install one and your method works great. Deffinately a worthwile investment.

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Yes, I think you too. Steve.
I'm going to try this. :yep

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Steve ,
These are the photos I was looking for about a month ago!!!
I replaced the refrigerator ( tiny , dinky, useless) in my 81' Burro with a window ac unit.
Having the vents already mounted saved a lot of heartache.
I pretty much did the same as you except I made a sheet metal cowling for the exhaust part and I added a sheet of 3/4 inch foam insulation on top of that to keep the heat confined to the exit area only.

Someday I'll con my daughter to bring her digital camera over and post some photos

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Orginally posted by Steve Tonnesen
<img src=http://www.fiberglassrv.com/board/uploads/3e5d7fcc4f549AC Side View.JPG/>

question: :wave you need two vents from the outside. one for incoming and the outgoing which neither mixes with the inside air. right. or will one outside vent work?

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Are ya there, Steve, because Jana's not the only one with a question. :wave I was under the impression the air intake on my unit was from the front because that is where the removable (for cleaning) air filter is. Am I wrong? Am I confused? Where is your air filter? The side vents or "gills" don't seem to do much of anything on my unit. What is their function, assuming all of these small side-vented units are pretty much the same. Can you please explain?

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Any heating & air conditioning guys out there?

I am probably using the wrong terminology, but my understanding is that the room air intake is on the front of the air conditioner, and it pulls room air into the air conditioner, cools it on the cold side coils, and blows it back into the room.

The exhaust from the rear is air blowing across the hot side coils and then outside. The purpose of the exhaust air is to carry the heat away from the hot side coils and into the atmosphere. Am I correct?

I am really curious, as I expect to be installing an AC in my closet this summer.

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The terms intake and exhaust are confusing for heat exchange devices for the simple reason that there are actually two separate intake and exhaust loops, on pertaining to the cooling coils, called the evaporator, and one pertaining to the heating coils, called the condensor.

An air conditioner uses electricity to pump heat from one side of a system to the other, but both have circulation loops over the coils. On the inside, the "exhaust" is where the cool air comes out, while the "intake" is the area usually right behind the filter. On the outside of a typical room unit, the "intake" is the vents on the side of the case, while the "exhaust" is where you feel hot air coming out the rear surface of the condensor.

My design simply accomodates the fact that since there is nowhere on the sides of an internally mounted AC from which to draw fresh air anyway, cutting away the sheet metal allows the fresh outside air to be drawn in from the top vent, so to be available to be blown through the condensor to the ouside through the bottom vent. Theoretical optimization would require the relative sizes of the vents to be the same, but maximizing efficiencies was not as important in this case as working with what I found.

To review, there are two air loops here, one using the inside the trailer air mass, blowing over the cold evaporator coils, and the second using the outside air mass (via the vents), blowing over the hot condensor coils. The AC can then pump the heat out of the air inside the trailer and into the air outside the trailer.

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Orginally posted by Thomas and Janifer

<div class='quotetop'>QUOTE

Orginally posted by Steve Tonnesen
<img src=http://www.fiberglassrv.com/board/uploads/3e5d7fcc4f549AC Side View.JPG/>

question: :wave you need two vents from the outside. one for incoming and the outgoing which neither mixes with the inside air. right. or will one outside vent work?[/quote]


Yes, for any kind of effieciency or effectiveness, you really need two vents connected to the outside, one for intake from the outside, and one for exhaust to the outside. On my Scamp, the small top vent is the intake and the large lower vent is the exhaust. It really works pretty well, and I am very pleased to see that others have benefitted from the design I showed in my earlier post.

When working with this stuff, remember that you can take a lot of liberty with design. I had entertained the idea of leaving off the outer cover of the AC wall unit altogether in order to save weight, but the case was part of the support for the condensor with my AC unit.

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Okay, so I was thinking correctly. the two outside vents need to be seperated so the air loops outside the trailer and not inside around the back of the ac unit.
now I have to hunt another vent cover. :wak

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Thank you, Steve - that was very informative.

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I just completed the cosmetic work on my AC installation following Steve's method. I also used a smaller vent on the intake and was amazed at the suction it produces when running. I think the vent size is perfectly adequate. I was also surprised to find that once I insalled the vents, the hot exaust was blown downwards quickly enough that it wouldn't get sucked back into the intake. I was able to place my AC lower in the closet (on the floor) than Steve and only lost about 16 inches of closet space. We don't usually hang clothes while camping anyway!!

For the intake vent, I purchased a soffit (eave) vent from Home Depot for 94 cents. It is alluminum, has screen attached on the inside and is designed for outside use. For the exaust vent, I also purchased a larger soffit vent, but cut my hole too big and had to replace with a return air vent intended for home heating use. It is heavier and because it is intended for inside use, I painted it and siliconed window screen on the inside. It cost about $3.50 from ACE hardware. I used stainless steel screws and plenty of silicone to give a tight seal.

I used a sheet of rubber under the AC to absorb vibration, styrofoam isulation on each side to block the side vents and seal the unit and attached a drain hose to the AC drain and elbowed it through a well siliconed hole in the bottom of the camper. I purchase the 5200BTU AC (kenmore) at Sears last week for $88 on sale and spent about $14 on misc. parts.


I ran the AC yesterday when it was 88 deg outside and about 80% humidity. The temp inside the camper started at 95 deg and 69% humidity. Within 40 minutes it was 84 deg and 39% humidity. 2 hours later is was 79% and remained at 39% humidity. I checked again after another hour and it was 74 deg and still going. I decided this was proof enough and shut it off. All in all, it was a great investment for about $100.

I appologize for not taking "during" pictures, but any questions I will be glad to answer.

<img src=http://www.fiberglassrv.com/board/uploads/3f03feff51117100_0110 (Small).JPG/>
<img src=http://www.fiberglassrv.com/board/uploads/3f03ff0e745a7100_0111 (Small).JPG/>

<img src=http://www.fiberglassrv.com/board/uploads/3f03ff2120e88100_0112 (Small).JPG/>
<img src=http://www.fiberglassrv.com/board/uploads/3f03ff2d34751100_0113 (Small).JPG/>

<img src=http://www.fiberglassrv.com/board/uploads/3f03ff3c6f95b100_0114 (Small).jpg/>

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Hi
Nice looking job on A/C.:wave

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Looks beautiful, Adrian! And I have some questions: what time of day were your humidity and temp measures taken; was your trailer at any time in the shade; what is the interior of your trailer lined/insulated with?
Am I the only chicken afraid to cut yet another hole in the side of her Scamp - especially in the closet area, which is supposed to be of special structural value? (I guess so, as I see there are no quaking smilies.)

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The temperature and Humidity test was ran during the afternoon (about 1pm to 5pm). We are primarily interested in cooling the Scamp at night since we spend most of the day outside when camping. I don't think we will have a problem, in fact, I think we will end up getting up and turning the thing down!

The Scamp is sitting in full sun outside our house. The photos were taken at 3am this morning, so they aren't a good example. I did have the curtains drawn which I would expect made a difference.
The trailer has the regular foil/bubble wrap type of insulation, covered in carpet that Scamp uses.

The hole I cut and the part of the closet I took out didn't do any structual damage to the Scamp. I didn't cut out any vertical support completely and with the shelf and the AC itself I think it may be better braced than before. I was very concerned (and you should have seen my wife's face) when I had to cut a hole in the side of the Scamp! But it worked out fine. One warning though...don't be as stupid as me and cut it without a shirt or socks on! Gloves would be a plus too as fiberglass is extremely itchy (for about 3 days) when it gets lodged into your skin!!!

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3 A.M.!!!!!!! Were you up all night scratching? Thanks for the info though. I already have one hole in the side with enough clearance around the AC that I think it will be OK for my purposes. Nice to know there is a workable alternative if I change my mind.