Trouble with AC box

[krunchbubble]

i have a 25000 btu window air conditioner, built a box for it with a 4" intake and a fantech fkd 8 exhausting the air from the box. the box is not that much bigger then the air conditioner.
problem is the condenser will turn on for a few minutes, the box will get hot from the heat, almost to hot to the touch. then the condenser will turn off for 20 minutes or so to cool down and restart. im sure and an ac guy says that the condenser is overheating ad shutting down.
what can i do? this has been a big headache for a few days now. thanks guys.....

 

[RoomRaider]

The A/C is totally enclosed in the box? Doesn't matter how many BTUs the A/C is, the air venting from the back will be way to hot, and too much of it for the A/C to cool.

If you are using only a 4 inch opening to vent the hot air, that is not enough, then entire backside needs to be open, or a 400+cfm fan could move it quick enough.

You will need the back half sticking outside the box, so that the hot air it produces can vent.

Thats why you always see them half in half out.

 

[FullMetalJacket]

You need an exhaust on the rear of the AC( and intake if you wish). The front and back are dividied and do not pass air.

On the rear(hot side) of the AC you need to pass air in the sides, top and bottom and exhaust it out the very back. If you look at the rear of the AC under the steel that is what the internal fan is trying to do.

I keep my sides passive top and bottom (of the rear hot section) passive and have basically built a box just to extend the very rear and just exhaust air from it into a vent and outside. Hard to describe but basically my rear box lloks like it is pust pressed up next to the rear of the AC, not around it...

 

[krunchbubble]

no the ac is not totally enclosed, the front is sticking out. not using a 4" hole to vent the air, thats the intake. 8" fantech fkd is the exhaust. why would the back half be sticking out? wouldn't that defeat the purpose of a ac box? i do see them half in half out, but the front is sticking out.

 

[FullMetalJacket]

RoomRaider is right, AC units generate more heat than cold in their entirety. The most effecient way is to have the AC half in and half out of the room. It is not neccesairy though of you seal off the rear of the AC and vent that out of the room. The rear will still generate some passive heat but not nearly as much...

 

[krunchbubble]

fullmetaljacket , that makes perfect sense.....

 

[DIGITALHIPPY]

you need to make a bigger intake, and dont have the fan sucking the hot air out, have it push cold air in.
u need atleast 8" tubeing, and u need atleast a foot of room for the box to have space between the back of the a/c and the back of the box wall.
a 6" w/9" 666cfm fan barly keeps my freakin 5,200btu a/c cool....
i feel bad for your badass 25,000btu...
its never going to get to be 10k btu if its not getting cooled. just hang the bitch out the window... or attic.

 

[seebobski]

ac box

ac box

if you look how air enters and exits normally.it enters from the sides and top.the air exits out the back to cool the evap-coil.so the problems with the ac box is where the air cycles thru the ac. you are heating the compressor tooo much!!!!
it will take a little more room but cool the way the ac is made. good luck

DIGITALHIPPY your constuction looks great if you are still having problems
you might rethink your exit out the box.I love the shed you had

 

[krunchbubble]

alright, cut a 5" by 18" hole in the bottom of the front of the box. ac does not shut off anymore! yay! i dont think the fantech is pulling all the heat from the box as i can feel a little come out the new hole. so i guess i need to step it up to a 10" and set up my other 25000 btu ac box.

 

[DIGITALHIPPY]

krunchbubble
im glad you got the problem solved.
id HIGHLY HIGHLY sugest putting the fan BEFORE the exhaust, having all that hot air go through it WILL decrease its life. dont want to see it burn out on you while your away.

DIGITALHIPPY your constuction looks great if you are still having problems
you might rethink your exit out the box.I love the shed you had

im not having any problems ATALL. except noise. i already moved it, just re-routed exhaust. my a/c is little.