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FFRA051ZA1 Window A/C unit CREATING humidity?

zeppelin111968

Premium Member
Joined
Apr 15, 2020
Messages
2
Location
FL
Model Number
FFRA051ZA1
Brand
Frigidaire
Age
Less than 1 year
Hello, i have some questions that i just can't seem to find or figure out the answers to and hopefully you can help. I recently bought a Frigidaire FFRA051ZA1 5,000 BTU window air conditioner. For a 150 sq ft bedroom occupied by 2 adults 1 infant and 2 dogs. My window around the unit is completely sealed the HVAC vent in the room is sealed and the door is kept closed and i have noticed a humidity problem i never before had UNTIL i installed this window unit.

When the compressor is on it dehumidifies the room say down to 50 percent once that compressor in the unit kicks off ill watch the humidity percentage rise drastically on the digital thermometer that i have. I'll watch it rise probably 10 percent within maybe 20 mins when the compressor kicks off. So say 60 percent humidity now and compressor kicks on and brings in down to 55 then compressor kicks off and humidity rises to 65 and so on and so forth until it's in the 70s and then i can't take it no more and open my bedroom door which then dehumidifies the room. There's no running water in here no bathroom nothing to give off moisture.

Before i had this unit and was using the HVAC system the temp would be set to 76 and i would keep the bedroom door closed but it would get hot in here up to 81 degrees before i couldn't take it and had to open the door to cool the room. BUT humidity would stay around 55% with the door closed before this window unit was installed. And since the air was kept at 76 or 77 it rarely kicked on and when it did not much air came through the vent. So i don't understand why i did not have a humidity issue UNTIL i installed a window unit. I've had this window unit bring the temp. Down to 70 degrees and when the compressor kicked off the humidity would rise to 60 percent or more while the temp. Stayed at 70 degrees.

I have gotten the temp down to where i like it as well as humidity (from opening and closing bedroom door)and manually turned the unit completely off and the humidity would not rise as it would if the compressor turned off and the fan stayed running. The humidity only drastically rises when the compressor stops running and the fan continues running. I also thought this unit was bringing in the humidity from outside when the fan stayed on after the compressor turned off until i found out that this unit has a closed vent system so it recirculates the bedroom air not bringing in any outside air.

Which now has me confused as to what is happening and why the humidity rises dramatically once the compressor kicks off and the fan stays running. This humidity issue only started AFTER i installed window unit. Why do you think this is happening? Will a different window unit solve my problem?
 

Dan O.

Appliance Tech
Staff member
Joined
Oct 9, 2004
Messages
3,168
Location
Canada
The main part of the air conditioner is outside the window right? All side and rear vents outside the room?

image.jpeg

It's tilted lower at the rear to allow recovered moisture to drain to the outside?



I've never heard of a window air conditioner adding humidity to a room. About the only possibility is maybe the condensation remaining on the evaporator after a cooling cycle is over is being blown back into the room by the fan. But the amount of moisture should be considerably less than what was in the room to begin with, not more.

Some A/C models have an 'energy saver' setting where the fan stops running at the same time the compressor cycles off. That would stop any chance of residual moisture left on the evaporator from being recirculated. It doesn't look like your model has such a feature. All I can suggest is manually stopping the fan when cooling is no longer taking place to see if that changes anything.

Dan O.
 

zeppelin111968

Premium Member
Joined
Apr 15, 2020
Messages
2
Location
FL
Yes, all side and rear vents on the unit is on the outside of the window. Manufacturer recommends tilting the unit back between 2 and 4 degrees so i leveled the unit in the middle at 3 degrees just to be safe. However this unit does not have a drain plug it only has an "overflow drain" which is sealed up with a plug and the manufacturer recommends leaving that plug in the over flow drain for energy efficiency. However i took the plug out just to test what it would do and doing so did not solve my problem. appearantly this unit keeps water on the bottom of the pan so that the fan can pick the water up with a sling and then sling that water on the condenser which has something to do with energy efficiency. Though it sounds like a way humidity can be put back into the room. I have read somewhere else that this feature could possibly be the cause for creating humidity. I just can't get a straight yes or no answer if this is my problem and if buying another unit would solve the problem or waste my time taking out this unit and installing a new unit as well as wasting my money just to have the same humidity issue. I have gotten the temperature and humidity down to where i like it then turned the unit off and humidity did not rise as drastically as it would leaving the unit on with the fan running and condenser off.
 

Dan O.

Appliance Tech
Staff member
Joined
Oct 9, 2004
Messages
3,168
Location
Canada
zeppelin111968 said:
appearantly this unit keeps water on the bottom of the pan so that the fan can pick the water up with a sling and then sling that water on the condenser which has something to do with energy efficiency.

That's right. The water evaporates when it is flung onto the condenser which adds to the cooling process without using any power. It's free cooling.

Though it sounds like a way humidity can be put back into the room.

No it can't. The inside and outside parts of the a/c are separated by the structure of the unit. That water and the condenser are outside the room. There's no way for that moisture to get back into the room if the air conditioner is mounted correctly, which is why I asked about its installation.


I'm afraid I have no idea how the air conditioner could possibly be responsible for your stated symptoms besides what I mentioned previously.

How close the the a/c's air output are you testing the humidity?


Dan O.
 
G

Guest

Guest
Think of it like this, on a hot day when you have a cold drink you get water condensation on your glass. Moisture is drawn from the hot air surrounding your glass and condenses on the glass. The same thing is happening with your room. Because it's colder than the rest of the house moisture, or humidity, is being drawn to your room. For optimum humidity control the air conditioner in your room should actually be set to 74°F. If it's possible you can leave your door cracked so the temperature in the room will rise faster than the humidity before the compressor cycles on again. Hope that helps!
 
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