A/C problems

[XxXBDrockXxX]

I put my a/c in the cabinet in my galley going into the main cab. The problem I'm running into is its getting way to hot and it is starting to over heat. I could really use some ideas on how is help the heat or even any other places to put the a/c?

[Ageless]

Window units have to have the coils and sides totally exposed. Placing it in a cabinets invites overheating. As you have 110V available; get a fan to pull the hot air away.

[asianflava]

I'm guessing that you are talking about a window shaker unit?

You have to vent the rear and sides of the unit, you also have to prevent the intake air (sides) from mixing with the exhaust air (rear). If you don't, the intake will draw in preheated air and the unit will overheat.

This is how I vented mine, the center has a ramp that vents the exhaust air out the top. The sides draw air in from the back, there is a vent under the ramp. I've used this setup for 4 straight days in 100+ weather without it overheating or freezing up.

[dh]

If you have clearance on the sides/back a simple baffle to seperate intake frome output and seprat vents in the floor for in and out should fix it. Also make alotments for the condensation to run out of the unit safely. You might wake up in a water bed, or worse, cause water damage inside.

[planovet]

You have to vent the rear and sides of the unit, you also have to prevent the intake air (sides) from mixing with the exhaust air (rear). If you don't, the intake will draw in preheated air and the unit will overheat.

That's what I did and I have not had any problems with overheating, even in 100+ weather.

Here is how I vented mine: Link

[steve smoot]

I have noticed that several folks placed the AC inside the galley area. Also, it sounds like this works well, if you vent the area.

I am looking at placing the AC under the bed. The front of the unit will face the rear of the camper. How would I best vent this area so the AC works.

Here is a photo of the bed platform. The AC would be in the large opening to the left, down at the floor level.

[caseydog]

As already stated in other words, you need to...

1. Provide a way for fresh outside air to get to the vents on the side of your AC unit (intake air for the condenser coils)

2. Provide a pathway for hot air coming off the back of the unit to get out of the camper.

I simply put vents in my galley to let fresh air in, and build a box on the back of my unit that channels hot exhaust air to a marine vent on the side of my TD.

If you look at the photo below, you can see the the box for the back of the AC unit. On the side of the TD, you can see a tall vent with louvers, which allows fresh air into the galley area where the AC unit is. Behind that, you see a rounded vent that covers a four inch hole where exhaust air leaves the galley.

Both vents have bug screens to keep the critters out.



CD

[steve smoot]

Thanks CD, I should be able to do something similar.

Would the smaller size vent, like your exhaust vent, work for both fresh air and exhaust. I have room for two of these on the side of my camper, but not for the taller vent.

I suppose I could put one smaller vent on each side of the camper to supply fresh air, if needed. And, I could cut the exhaust hole in the floor??

Oh, and what did you do about the condensation from the AC?

Steve

[bobhenry]

Can I show myself to be a complete idiot by asking a real dumb question?

If the side vents are for cooling would it be of any benefit to draw inside cooled air to these side vents. I realize you wouldn't do this in a 15 x 15 room with 9' ceilings because it robs the cooling delivery of the unit but we are talking about a 250 cubic foot "room" not a 2025 cubic foot room so we have cooling to spare.

Would this add any thermal effeciency by cooling the condenser farther than usual ?

I'll go set in the corner now

[caseydog]

Steve, you could use two of those exhaust vents. If you want to vent anything to the bottom of the TD, why not the intake. Blowing hot air out the bottom is working against what hot air wants to do.

Bob, some people do what you are suggesting to keep the 5,000 BTU units from cycling on and then right back off in a minute or two. So, yes, you can do that. A 5,000 BTU AC can cool a TD off so fast that the AC has no chance to run and de-humidify the TD. Using cool cabin air to cool the condenser can make the unit run a bit longer.

CD

[steve smoot]

Thanks CD, I believe we are gettin' somewhere now...

I will build a box behind the AC to capture the hot exhaust and pipe it up and over to the side. I will use the same vent you have.

I will put an intake grille to the right of the AC to pull cool cabin air for my supply-return air.

Steve

[dh]

Remember, the AC "recycles" cabin air. If you want to suck air out to vent the AC, you will need a way to let air in.

[bobhenry]

Man a quadruple post not just everyone can do that !


WOW!

[steve smoot]

Remember, the AC "recycles" cabin air. If you want to suck air out to vent the AC, you will need a way to let air in.

Okay, so all is well, if I just add the supply air vent to the outside wall, like CD told me to start with...

Thanks,

Steve

[Larwyn]

In my installation air is drawn up through the floor for intake air and the exhaust is blown directly out the back of the TD. I have an additional vent to the intake air box, both to allow cabin air to mix with the intake air and as an intake when using the Fantastic Vent for circulation. When there is no shore power for the Air Cond, that little vent at the foot of the bed allows fresh cool air from under the TD to be drawn in rather than only having the widows/doors for air flow.

I allowed for intake air on both sides of the A/C unit because someone suggested that I should allow the same square area (square inches) for intake as the existing louvers on the case allowed. Not sure if this is essential but it cools the cabin down quickly, dehumidifies well, does not short cycle and does not overheat. The exhaust air exits unrestricted out the back is totally isolated from the intake on the sides.