Hi all, I've been reading posts from HVAC-TALK for a while, decided to ask for advice here

Question
Does other air conditioning units cause humidity to increase as a side-effect? What could be the reason of this problem?
(My room is <30m2's and the unit is ~18000btu's - however the room isn't tightly separated from the home - a dry home at ~ 22-25 degrees)

Thanks in Advance

Yes, the cooling of the air raises the %RH to near 95%RH as moisture is removed. As the cold dried air is mixed with the warm air in the room the average %RH is lowered. If water is draining from the unit, it is working. Get a good dehumidifier to go with your a/c.
REgards TB

 

Thanks a lot for the answer, the water was initially pouring, however after the unit got de-installed the first time, an extreme amount of water poured from the unit/drain, so I made the installers improve the slope/installation

What's strange is that, intially the RH drops to lets say 45% - at 22 degrees, at that point the AC halts, and the RH slowly increases

Lets say the room is normally at 24 degrees, AC off for hours, and when the AC is set to 26 degrees at COLD, normally it should only circulate air to measure the temperature, and the temperature RH should stay ~ at same levels, however in these cases humidity always increases to > 60's from 40's

I'm also thinking whether the problems are caused by over-sized BTU issues, or air/humidity movements caused by temperature difference etc, however the last situation I mentioned discards my theories and makes me think the outdoor unit is pumping humidity through the humidity hose (I check the water line on the indoor unit, there is a minor amount of water, seems like a leftover rather than a collection)

I'm considering getting a de-humidifier, can't be sure whether the de-humidifier can pull humidity fast enough to match AC's humidity generation
I'm also considering running the AC continuously at AUTO mode and getting a de-humidifier, humidifier to keep the RH level around 50%, however it seems like an overkill, waste of space/energy/money, turning off the AC when it starts idling seems more logical

 

I'm thinking TB should do a field visit and report his findings? does the fan continue to run after the setpoint is reached?

 

yes, slowly, also a minor hissing sound that lead me to believe a humidification routine is running

What's strange is all the devices in Turkey are made in 2008, 5 years that's a very long time, I'm thinking the filters might even degraded by this time

 

That unit actually has a HUMIDIFICATION feature as well as a DE-HUMIDIFICATION. It sounds as if you may have a problem with the HUMIDIFICATION feature. The system will absorb moisture from outside and move it to the indoors.
When operating properly, this system will act as a stand alone de-humidifier.

It sounds as if you have it in the "MOISTURE COOLING operation" mode. You should be using the "Sahara Dry" mode if there is not a lot of cooling load or "Dry Cooling" mode if there is sufficient cooling load.

 

Wasn't the case, on Sahara Dry / Dry modes, it still creates moisture, the new unit is much better than the older one, doesn't cause any problematic amounts of moisture
The unit also humidifies the air, on whatever mode it is on, I'm guessing it's part of the cleaning function, however the moisture problem I'm talking about is different.

Not keeping the unit always on solves my issues, didn't had any problem with the new unit, haven't really tried it on heating modes, whenever I turn the heating on, the humidity jumps up to 60's from 48's, immediately, hoping it's a temporary thing