Possible problem with window AC.

[Swift101]

Hey Everyone,

Last year I bought a Sharp AFQ120VX (12K BTU) window air conditioner for my apartment. I keep the door open to my bedroom and let it cool down my entire place(500 sq ft). It typically cools down my bedroom to 70 degrees and keeps humidity below 45%, even on the hottest of days.

However last night I woke up sweating, when I went to check what setting it was on I noticed the "cool" light was flashing and the compressor was off. I powered the unit off and put it back on after 30 seconds. The light stopped flashing and the compressor came back on. I had the temperate set to 62 degrees since I like it cold, but maybe it was too much for the unit to handle?

I've had Panasonic through the wall ACs in the past and was able to max them out for days without any problems. It's still under warranty so I might give Sharp a call about what happened. Has anyone experienced a problem like this?

-Thanks

 

[burchster13]

When I was growing up (1990s) our central ac from the late 70's would always freeze up at night and quit cooling so maybe it was set to low and froze?

 

[Rtstrider]

I'm with Burch on this one. I'd say check the coils because if the humidity's too high and the unit is set too low the coils can freeze. Also have you checked the filter to make sure it's clean? Last question....How about getting a can of $5 coil cleaner from Home Depot and cleaning the outside coils?

 

[SrDriver]

Am retired and did HVAC work for a living.

Any setting below 70 degrees will cause problems as mentioned above.

Setting the unit to a lower temperature will not cause it working better.

Try 72 degrees + make sure that the filter is clean.

 

[Rand]

This is a window AC not a central. I only have heard of problems when the outside temp is below 60F

I keep my attic(office) ac on 66F quite frequently the room is only about 125sqft but the walls can reach 90F+ It works quite fine. Its a GE 6000?BTU unit.

Sounds like your Sharp AC might be a Dud. You should check the filter and see if its icing up or what the problem is if you can.

 

[supton]

Our window units kick off when outside temps hit 67. So we will run ours all day to avoid cooking at night.

 

[Swift101]

Thanks for the feedback everybody, I'll try setting it at a higher temperature and see how it does. I think the temperature outside never went below 75 last night.

Also I just cleaned the filter last week,if It happens again I'll inspect the coils to see if they are in fact frozen over. And I'll probably get a can of coil cleaner as well.

-Thanks again!

 

[sleddriver]

Set at 62°, I'm willing to bet it never went off. Setting the temp low doesn't mean the air coming out is any colder, however it will mean it will run longer. Sounds like it sensed it was in danger of freezing up and went into self-protect.

I'd suggest a fan large enough to move air from the room where the unit is in, into your open bedroom door.

 

[Nick1994]

Originally Posted By: sleddriver
I'd suggest a fan large enough to move air from the room where the unit is in, into your open bedroom door.
Yup, use a fan to help it push the air around and it probably won't run as much.

 

[aquariuscsm]

Years back we were running a bedroom window unit and turning off the central ac (we like it cold at night too) every night. Ours would do the same exact as yours,it's start blowing cold air and if you turned it off for awhile and restarted it,it'd begin to blow cold again.

Anyway we eventually quit using it once we got the electric bill and saw how high it was. The window unit cost more to run than our central unit. Window units are very inefficient.

 

[zzyzzx]

I also have issues with window AC if it gets cold enough at night.

 

[ARCOgraphite]

I dont see the evap coil freezing up if they humidity is low and the airflow is OK. I do see the superheat being offset to a point where the evap would send liquid refrigerant to the compressor and the unit would failsafe at this point.

Come on, if its cool out, shut the things off. Your like my neighbor with his window ac running all night - it got to 61 deg F last night (from a high of 87 during the day).

 

[JHZR2]

Today is a scorcher again, but nights are still going down to around 70 outside. Id run it again and try to duplicate... If it happens, take off the front/filter and get a look at the coils. Any sign of ice?

I suspect that there was just enough moisture and ice at the thermistor that it triggered a fault, but is a dud. If it was severe, Id guess that it would work equally bad after turning it off and on. Since it seemed to work fine after three minutes, I suspect it was a glitch.

That said, as was mentioned above, setting it to a lower temperature doesn't cool any faster. These machines are a set compressor design and doesn't "throttle". It removes a given amount of heat from the air per hour regardless of what you have it set at. Only difference if you set it too low is that it may never cycle. That cycling can help ensure that no ice builds up...

 

[bullwinkle]

Might be running low on refrigerant-if you see ice forming in the area where the little capillary tube is soldered onto the bigger evaporator coil, could be a sign of a slow leak-esp. If you've it run it on this setting before without trouble. 62F is pretty low, try it at 68 & put a small fan on your floor by the doorway to push the cold air out of the room into the rest of your place.

 

[Rand]

Originally Posted By: aquariuscsm
Years back we were running a bedroom window unit and turning off the central ac (we like it cold at night too) every night. Ours would do the same exact as yours,it's start blowing cold air and if you turned it off for awhile and restarted it,it'd begin to blow cold again.

Anyway we eventually quit using it once we got the electric bill and saw how high it was. The window unit cost more to run than our central unit. Window units are very inefficient.


Depends on the unit.

My 11.x EER? 6000btu unit pulls about 400watts running.
much more efficient than my central air running an extra 2-3 hours a day to keep the upstairs office(finished attic of a cape cod house) cool.

it runs maybe 50% of the time I usually keep it at 66-68 because of the shape of the room it cools unevenly. However adding a 50watt fan to move air around just uses more power. It also has a timer and I'll set it to kick on an hour before I get home from work. Takes about that long to go from 90f to 75f

Downstairs is usually on 73f-75f depending on cooking, TV etc.

of course my house HVAC is horrid with a central collector return. IT does have a nice shiny new carrier AC and 95% efficient gas furnace.

 

[Al]

I have never had a window unit freeze up. That just doesn't happen anymore provided the filter is not totally plugged up. My window unit in my bedroom will get the bedroom down to 65 even if the outside temp hovers around 60F.

 

[GiveMeAVowel]

Like another poster mentioned it is VERY important to
keep the evaporative coil facing outside clean. Most folks don't realize that there is NO filter for this and over time especially if you have a lot of debris from trees, shrubs grass, dirt, ect it will block the fins and stop the exchange of hot air.

If possible turn the unit OFF first and get a garden hose with a spray nozzle and spray directly straight into the coils to clean them off (the clogging happens in the inside of the case so you can't see the blockages. Continue to spray head on for around 5 minutes on the entire surface of the evaporator. Do NOT spray at an angle you don't want to bend the fins with the water pressure, just aim the water jet head on spraying from the top of the evap to the bottom in a straight line up and down.

 

[sleddriver]

Originally Posted By: GiveMeAVowel
Like another poster mentioned it is VERY important to
keep the evapoartive coil facing outside clean. Most folks don't realize that there is NO filter for this and over time especially if you have a lot of debris from trees, shrubs grass, dirt, ect it will block the fins and stop the exchange of hot air.

If possible turn the unit OFF first and get a garden hose with a spray nozzle and spray directly straight into the coils to clean them off (the clogging happens in the inside of the case so you can't see the blockages. Continue to spray head on for around 5 minutes on the entire surface of the evaporator. Do NOT spray at an angle you don't want to bend the fins with the water pressure, just aim the water jet head on spraying from the top of the evap to the bottom in a straight line up and down.

The evaporator coil faces indoors, not out. The outdoor coil you're referring to is the condensor!

 

[Swift101]

Just a quick update, I set the temperature to 68 last night and setup a fan by my bedroom doorway. As expected it helped cool down the room quickly and kept it cool all night.

I appreciate everyone input and advice! It's a great pleasure to be part of a community with so many knowledgeable people. Thanks!

 

[aquariuscsm]

Originally Posted By: Rand
Originally Posted By: aquariuscsm
Years back we were running a bedroom window unit and turning off the central ac (we like it cold at night too) every night. Ours would do the same exact as yours,it's start blowing cold air and if you turned it off for awhile and restarted it,it'd begin to blow cold again.

Anyway we eventually quit using it once we got the electric bill and saw how high it was. The window unit cost more to run than our central unit. Window units are very inefficient.


Depends on the unit.

My 11.x EER? 6000btu unit pulls about 400watts running.
much more efficient than my central air running an extra 2-3 hours a day to keep the upstairs office(finished attic of a cape cod house) cool.

it runs maybe 50% of the time I usually keep it at 66-68 because of the shape of the room it cools unevenly. However adding a 50watt fan to move air around just uses more power. It also has a timer and I'll set it to kick on an hour before I get home from work. Takes about that long to go from 90f to 75f

Downstairs is usually on 73f-75f depending on cooking, TV etc.

of course my house HVAC is horrid with a central collector return. IT does have a nice shiny new carrier AC and 95% efficient gas furnace.


Yeah I can't remember what it was (fridgidaire I think) but everytime it'd come on,the lights would dim and it just seemed to suck up a bunch of power. The central unit is huge,and barely has to run to keep the entire house cold.