Air Conditioner.. facts?

Factual Questions
1

Every single year I have lived in my current apartment, Spring turns to summer and my apartment issued in-wall air conditioner will begin to act up.

Every Year.

Symptoms are pretty much the same each year… No matter how much cooling I set the air conditioner for, it will cool to approximately 15-18 degrees below the ambient air temperature in my apartment, stay on for about 1-2 minutes, then the condenser stops and the fan continues… 15-20 minutes cycle begins again.

I clean the filter pretty religiously, I have two cats, I smoke a pipe, and there’s a couple litter boxes in the same room as the air conditioner so I know cleaning the air intake is important.

Each year I’ve had to put up a fuss until the air conditioner gets swapped out. They usually try cleaning it first but that’s never improved the situation so I keep tracking it’s cooling abilities and call them if their cleaning doesn’t fix the problem.

Now in contrast to this… I have a free standing air conditioner I purchased for my bedroom. (I got it one particularly bad summer when the apartment folks were not going to have a replacement available for a week). It’s three years old now, and it actually runs year round. I prefer to sleep in cool temperatures and even if I drop the thermostat to off my apartment still gets to the mid 70s during the winter. So in winter I have it set to come on around 5:00 pm and turn it self off around 5:00 am. In Summer it’s always on.

This three year old air conditioner puts out air 20-22 degrees cooler than ambient and continues to do so until the room reaches the specified temperature and has always done so.

Differences… no litter boxes in the bedroom, I don’t smoke in my bedroom.

The apartment itself is ground floor, at the end of a U shape, facing east into a cement courtyard, and during summer I compare it to being inside a solar oven.

Can anyone who actually knows something about the inner working of air conditioners give me some idea as to whether there is anything I can do to improve this situation? Last year the Apartment manager went so far as to install a new (Not just swapped out of another apartment) air conditioner. It’s a Frigidaire Gallery so I’d expect something better out of it than what I’m getting.

2

Dollars to doughnuts, the units are oversized for the area it’s meant to cool. Use this BTU calculator to determine the proper size AC unit for your apartment. You can’t just buy an air-conditioner willy-willy and expect it to work properly. It’s important to match BTU ratings with the area to be cooled.

3

Air Conditioning Contracter stepping up to the plate…

I agree with Q.E.D. on the size issue. Some questions:

Does the unit have two fans (i.e. A blower motor and a condensing motor) or just one?

Does the fan always run?

Is the Thermostat built into the unit, or is it in another part of the room?

Has your apartment actually sent out an A/C Contractor to look at it or has it just been maitenence men?

If the unit is sized correctly, then it might be a Thermostat issues. If the T-stat is built into the unit I doubt this is the problem since the unit has been changed with the same results.

When I moved into my apartment the A/C didn’t work. I filed a complaint and waited until the end of the next day and took care of it myself. I billed the apartment complex and they took it off my rent. Perhaps you should call someone to help.

4

Well, you are keeping in mind that the air conditioner that does not function properly is not one that I have any say as to it’s size/btu capacity?

The unit that fails each year is the one that the apartment complex furnishes.

The one that works fabulously (that I purchased out of desperation) is a 7,500 btu/hr Danby (DPAC7599) free standing unit. (Though having to empty the water tank every day is a bit of a pain.)

The Frigidaire Gallery that the apartment management put in last year has a little information … Model FAH126J2T2, Rated at 12,000 BTU/HR. The area to be cooled is a one bedroom apartment. No good aprroximation on square footage, but the apartment layout is basically like this though the placement of the air conditioner in the diagram doesn’t match my apartment… it should be placed to the wall side of the sliding glass doors, not in the center of the wall.

And can you clarify why a unit that’s oversized for the area it’s ment to cool is a bad thing? I’d think too much cooling capacity would just mean I could run it at a lower setting and get good results?

5

Sure. An oversized unit will cool the air near it so quickly that it will shut down, thinking the room has reached the desired temperature. It will repeat this cycle every few minutes, but never manage to run long enough to actually cool the whole room down. In other words, it will behave exactly as you describe your unit. I would bring this to the attention of the building management the next time you make them get you a new AC.

6

I am assuming that it has two as the fan stays on… it’s the condenser that kicks in for 2-4 minutes then off for 20.

It’s got to be built into the unit as there is no temperature control, just cooling level 1 through 10 and fan/cool high/med/low.

Well, I think they have all been just apartment maintenence men. Though the one who got me set up last year seemed to know a lot more about air conditioners than the folks who’ve helped previous years.

Ok… then assuming I am the complete home/apt. maintenence nincompoop that I actually am… Who should I call to help, and what should I tell them in order to actually get someone who knows what they are doing?

7

OK, this makes logical sense to me, but raises only one question. Why does this behavior exhibit itself only the second year that the air conditioner is present in my apartment? Once I finally get them to install a new unit the restof that summer goes fabulously. This exact air conditioner performed great all through summer and early fall.

If the issue was an air conditioner that cooled the air near it too quickly wouldn’t that show up right from the beginning?

8

I would think it would. I had thought that was, in fact, the case until your last post. Now, I’m at a bit of a loss.

9

I purchased a 10,000 BTU air conditioner because they sold out of the 7,500 models I went in for, to cool off my attic bedroom. I had a similar problem with my that air conditioner unit shutting off. I decided to keep using my box fan and set it near the A/C to circulate the air in the room more during the time the unit was actually on. I noticed immediately that the A/C unit would stay on much longer before shutting off. Assuming no other suggestions solve this little conundrum, perhaps you could try this.

10

This has sounded like a relatively inexpensive fix to attempt, but I’ve been puzzling about what direction to point the fan. The Air conditioner is mounted relatively high on the wall so do I want a fan on the floor pointing into the room, a smaller fan actually perches on top of the air conditioner pushing the cold air further out, or something near the middle of the room pointed right at the air conditioner to push the room’s real temperature toward the inlet where the thermostat is?

11

Additional diagnostic information… the amount of time between when the condenser kicks in and attempts to cool gets MUCH longer during the day (somewhere near 3 to 4 hours with just fan and no condenser) when the sun is shining on the metal box it’s contained in, and it’s duration as being on remains just between 1-2 minutes those few times it comes on.

As a stopgap hope that it is somehow related to being an overpowered air conditioner I’ve purchased a floor fan which is now pointed up and into the corner that the air conditioner is located in.

If I haven’t explained before, I am the king of overkill, so it’s a commercial grade Honeywell floor fan so it sounds like I’ve got a small jet in the corner. :smiley:

Current ambient temperature in the living room is 83 degrees and about 40% humidity. The AC just kicked on as I’m writting this, so we’ll see if it stays on longer with a man made high breeze pointing at it. time on 11:57 a.m. Lowest point the air temperature going out reaches 58.2 degrees . Time it kicks off… 11:59.

Am not seeing any feasible way that the air in front of this AC could have been cooled far enough to turn itself off via the thermostat.

I have a vague memory of the maintenence man who helped me last year saying something about the condenser motor overheating and then shutting itself down till it cools. This would seem to jibe with the time between cycles lengthening during the heat of the day. But as is the case with most of the reasons that it does this, it does not explain why it only becomes an issue by the second cooling season it’s operating.

The only thing that I can come up with is the fact that the metal boxes are in no way covered over winter and something happens to the AC unit hanging out there. I’m going to go outside and take a peek at the ventilation… There does not appear to be any blockage or accumulated detris on the back. There are some areas where the fins are bent, but no more than I consider “normal” for these delicate things once they actually get out of the show room.

12

So… the apartment maintenence person (who is new and seems to know his stuff, had proper tools to test charge, etc)

First he decided that the problem was likely to be the flange on the back… i.e. a metal fin that directs the hot air out away from where the compressor is drawing it’s air in. (makes sense, if you draw in the already heated air, it’s just going to get warmer and warmer until finally something shuts down.) Out came the air conditioner, down to the shop, where he adjusted the flange and sucessfully ran the air contidioner for 10 minutes in the shop before bringing it back to my apartment.

Cooled down nicely, held on for a full 5 minutes… just long enough for him to assure me that was the problem and get half way down the hall.

Thankfully he had no problem coming back in.

Next decision on what the problem must be… the capacitor. (Heck I didn’t even know air conditioners had capacitors. ) Ran it in the shop for 20 minutes this time (Makes sense to me… have the machine fool you once, that’s nobody’s fault, but twice?)

Brought it up… and it ran well, but… it fooled me this time. Previously (I don’t think I mentioned this before) when the compressor kicked out, it was loud and obvious… there was almost a thud noise when it kicked out. It didn’t do that anymore… it just quietly stopped cooling… only by watching the indoor/outdoor thermostat I’ve got juryrigged on it was I able to see exactly why it wasn’t getting any cooler in my apartment. I tried pointing my fan of Doom at it in case we now had reached the overpowered AC for the room situation but to no avail.

I called the front office again, luckily they hadn’t closed up shop yet. The gentleman who displayed expertiese had already left, but they were going to see what they could do.

They called back about 5 minutes later… two guys were avilable to swap my A/C out. Totally different caliber of guys… these were obviously general maintenence guys who really didn’t have training with Air Conditioners, but swapping in a new one in place of an existing one was well within their capabilities.

So… Now I have a brand spanking New Frigidaire Gallery model FAH126M2T1 cooling away… we’re at 30 minutes of soid compressor running.

I’m going to leave a message with the office that I’d really like to know if they figure out what’s wrong with the one they pulled out so we might be able to prevent this from being an issue next year.

So… experts in the field of Air Conditioning, weird mechanical failures and the like… do you folks have any advice on what I can do in order to avoid this happening to me again?