Window AC unit cold for only 10 minutes

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Old 07-29-11, 09:38 PM
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Window AC unit cold for only 10 minutes

I rent an apartment and am trying to understand an issue with the supplied air conditioner. Maintenance has swapped it out twice now, but the current unit (which they said they ran for over a day and puts out lots of cold air) is giving the same problem as the original. (Don't ask about the second unit! ) Both put out cold air reliably for about 10 minutes, then revert to what I would call "cool, moist air" for the next 45 minutes, easily undoing the original benefits. I'd initially taken the step of running them for just 10 minutes at a time, once an hour. I can always hear the "click" on the thermostat knob, which separates "compressor on" from "compressor off" mode. There is no switching the units on and off, or messing with the knobs in other ways to restart the compressor. It's always a waiting game. The current unit is an 8500 BTU White-Westinghouse, apparently recently serviced by a local repair company. The original was a Frigidaire. The room size is roughly 300 square feet.

My question: IS THIS NORMAL? I can't imagine so. The compressor is going to switch off at some time, but if I run the AC continually for a couple hours, the room should be ice cold.

My only idea: the air conditioner doesn't actually sit in a window, but in a metal sleeve embedded in the wall. So only the back end is totally unobstructed. (There is a little clearing on all sides, but not much.) Is it possible the compressor or another component requires cooling from the top, bottom, or sides, and is overheating and shutting off? I am actually even more concerned about this unit, because I have yet to hear water draining.

I would be very happy to hear suggestions. Thanks!
 
  #2  
Old 07-29-11, 11:24 PM
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I have seen apartment maintenance slide a window AC still in its case in side the case of a previous AC. If that is what they are doing it won't work well.

Of course here they almost always use window ACs for through the wall applications. From what I have read in this forum other places they actually seem to use purpose intended through the wall ACs. If the AC they put in the sleeve was a chassis only and fit then it may be OK. If though it was in a case, maybe a window AC and they slipped it into another case (sleeve) that may be your problem.
 
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Old 07-30-11, 12:28 AM
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Was just about to switch off the computer when I decided to check for replies. Thanks for responding!

Hmm, I am not sure of the difference between a "purpose-intended through-the-wall AC" and a typical window AC. There are no slide-out flaps on the sides to block off the remainder of the window, but these could probably be screwed off anyway. My guess is that it's a typical in-window AC. How would I know? If the problem is the design of the unit, that's a problem, because all the other tenants are using the same style AC units.

When a unit is removed, all that's left is the metal sleeve (with some debris in the bottom) and the grate at the far end with daylight poking through. There is only one metal sleeve, the one permanently mounted in the wall.
 
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Old 07-30-11, 12:35 AM
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Some pictures might help. http://www.doityourself.com/forum/li...your-post.html

You don't have the air intake open do you?
 
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Old 07-30-11, 12:40 AM
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A window unit will usually have louvers on the side in addition to the top whereas a through-the-wall unit will only have louvers on the outboard end. If the side louvers are being obstructed by the sleeve (through the wall) then it can't get sufficient outside air to cool the machinery.

The other possible problem is that many window-type units have a thermostat bulb fastened to the inlet of the cooling coil and it measures the temperature of the cooling coil in addition to the room temperature. Without sufficient room air at a high enough temperature the compressor will shut off to avoid freezing the condensed moisture on the cooling coil.
 
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Old 07-30-11, 08:35 AM
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Just so we are clear is this mounted in a window or is it mounted in a hole in the wall?
 
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Old 07-30-11, 11:46 PM
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Today I spoke to the part time maintenance guy, who explained these models are wall-mount designed. The model number is WAH09EH2T1, and I found references online that confirm this, for example: White Consolidated Industries Air Conditioner Recall . (I wasn't going to pull it out of the wall myself.) So does this disqualify all the advice so far?

Given that the unit does work very well (for about 10 minutes), my layman's understanding of air conditioners suggests that 1) something is still overheating, or maybe 2) there's a problem with the thermostat. Can the thermostat be adjusted internally in any way that might circumvent the external knob (i.e. when I set the thermostat at 100% cold, the unit thinks it's actually much less, maybe 25% cold)? Just some guesses.

Thanks again for any ideas.
 
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Old 07-31-11, 02:08 AM
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You really need to have a serious talk with management. They need to fix it not you.
 
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Old 07-31-11, 10:13 PM
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Umm...I am still soliciting input. Thanks.
 
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Old 08-01-11, 06:24 AM
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thetao, I'm looking for anything you can do to fix this and don't see it. I'm not an AC pro, but from the link you posted I would have a talk with management, with something in writing so they will have been notified, so that any fires related to these units become their problem if they choose not to act. There's probably a diplomatic way to word that so as not to put you in conflict with them, but you need to be sure they know about the recall.

Beyond that, if the sleeve and venting is as it should be, the unit should work.

Is your unit extremely humid, such that the ac might freeze up quickly?

Bud
 
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Old 08-01-11, 08:26 AM
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Given that the unit does work very well (for about 10 minutes),
If you are saying this to management that may be part of the problem. It does not work correctly period if it fails after 10 minutes and that needs to be what you tell management. They need to replace it.
 
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Old 08-01-11, 02:36 PM
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Sorry, I used that link only because it was the most straightforward mention of the AC's "in wall" design. I may mention the recall, but this was from 2001, and I suspect it was serviced long ago. (NB: I had originally pasted just the http link, not the page text. The editor apparently "reached out" and grabbed that text, something I've never seen before.)

Speaking of service, that's largely the reason I posted here. I was told the unit was recently services by a local repair company. If so, and if the repairman is a lummox, I wanted some input beyond saying "it doesn't work".

And I sort of figured it out. It's the compressor. When it dies, it remains dead for roughly an hour. Then right before it will restart, I hear a very faint metallic "ping" from inside the AC. It would seem to be a fuse/relay/etc. resetting. So either the compressor is overheating (or something) or the fuse/sensor is tripping accidentally. (When the 1-hour period nears, I was switching it on every 2-3 minutes, but the compressor would not switch on until after the ping.)

I will relay the above to maintenance, but if anybody knows more about compressors and fuses, I'm all ears.
 
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Old 08-01-11, 03:37 PM
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Not a A/C pro but, if the compressor was overheating it would cool down enough faster then an hour.

A fuse is a one shot deal. Once they blow they are dead.

Since this is not your unit (IE the building owns it) I'm not sure how far you want to take this but you could remove the outside cover and have a look see. Many cases there is a wiring diagram on the inside. You could look for an overload and check it with a meter while it is running.

Another thought: Maybe the building folks have bypassed the thermostat and set it to the lowest/warmest setting to save on electricity?
 
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Old 08-03-11, 01:34 AM
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Long story short: I contacted maintenance again, who had the AC service technician stop by this afternoon. He confirmed what I found, suggested the compressor was dying, and that fixing it would cost more than a new unit.

As maintenance was out of reconditioned units, I now have a brand new AC...with a remote control. Happy, happy! Thanks for all the feedback!
 
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Old 08-03-11, 09:52 AM
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Glad you got a new one. Thanks for letting us know how it came out.
 
 

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