Split AC makes my room cool but not cold


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Old 04-29-16, 11:58 AM
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Split AC makes my room cool but not cold

I own a 10-year old 1.5 ton SG split AC. Throughout I've dealt with minor issues - replaced the evap core once and had a leak fixed in the condenser. Also on a second 'used' compressor.

In the past month or so the cooling performance of my AC has dropped noticeably. It doesn't "chill" the room properly; the room temperature just feels cool, not cold. I've gotten it checked up from three AC guys, and I've even had the gas drained out, gotten a proper flush and refill higher quality gas.

The suction (thin pipe) and return (thick pipe) are both cold, the suction line colder as it should. The gas pressure is a-okay; measured at around 4 pm and it was 50 psi. I'm told it is in the 55 psi range and might go up to 60 psi or higher in the peak summer season, which sound about right according to a little research I did via Google.

There are no leaks. My evap and condenser are both clean. Filters are clean. So what's causing the AC to not pull warm and humid air out of the room properly and get chilled air to come out of the evap?

I should also mention when I pop the front cover open to feel the evap with my hands, it is cool and slightly humid to the touch not cold and dry. The air blowing out of the condenser is also warm not hot as it should be. The drain pipe is kicking out the condensed water properly but it isn't as dense as it should be - when my AC used to work at peak capacity, it would kick out a lot more water.

Everything according to the technician's gauge and "intuition" points to a system that is fine, yet the cooling has dropped by nearly 25% in the last month. It was running like a champ last year, in mid-summers I might add.

What do you make of this? A faulty TXV or capillary tube? A bad metering device? I'm just taking shots in the dark here. I've even tried having the gas level increased and decreased, but it makes no difference. Better quality of gas makes no difference. Is my evap or condenser about to go out?

The compressor's good too - it's drawing in the correct amperes (between 0.82 and 0.84). So I don't understand why the evap and condenser are not working as good. Whether its day or night, the AC's performance remains at "cool" and not cold.

Two AC guys kept telling me "pressures are good", there's no leakage, your system is performing as it should. I call BS on that because they did not see it performing a month back. Right now, at an 18 deg C setting, my AC performs as if it's cooling at a 26 or 27 deg C setting. Voltages are good at my home, no issues there.

I also should mention that the suction line freezes on start up for the first four mins and then defrosts. A few minutes later condensation can be seen on both pipes and they are cold to the touch. The evap, however, takes 3-5 mins to start blowing cool air and it takes more about 20 mins for the evap to reach it's max efficiency. As you can imagine, it takes a good 20-30 mins for the room to feel cool, let alone feel cold, as it used to. Also the moment I switch it off, my room starts to get relatively warm.

I have the same guys coming in tomorrow again to do a follow up, but I doubt if they will be able to trace the problem - if anything, they'll find a nice excuse to yank more money out of me - after all, hunting season is in. These vultures go to great lengths to prolong AC issues.

I need ideas and suggestions fast. I'm from Karachi, Pakistan - it's close to 38 degrees Celsius during the day at around 40% humidity, while at night it's 28 degrees C with humidity approaching 80%.
 
  #2  
Old 04-29-16, 02:16 PM
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Your problem is low on gas, you may have a leak. pressure is also too low.
 
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Old 04-29-16, 04:46 PM
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It doesn't matter where the thermostat is set..... the system only cools at one rate.

The suction (thin pipe) and return (thick pipe) are both cold
The thin line should be warm......not cold.

I agree with the low on refrigerant diagnosis.

Keep in mind.... on this site..... charging and system pressures are not discussed. Failure to comply will cause the thread to be closed or removed.
http://www.doityourself.com/forum/ai...ng-your-c.html
 
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Old 05-04-16, 09:39 AM
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Okay, I'm a bit confused - isn't the thin line referred to as the suction line which should always be cold? If it's warm, then there is almost no refrigerant. That's what every AC guy tells me, and I've researched this as well. I own a split AC system.

If I had a leak, all the gas would have been lost by now. Plus, there is no freezing/frosting on either one of the lines or the evaporator.

The air in my room smells funny when the AC's on, particularly when I switch it off. "Wet/gym Socks Syndrome" is what they call it I believe.

Need to find a reliable technician to clean out the evap and properly vacuum the system to get excess air and moisture out of it.

Thoughts?
 
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Old 05-04-16, 10:18 AM
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The confusion is because you are calling your "mini split system" a split system .

A mini split has the metering device outside so both lines should be cold.
 
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Old 05-04-16, 11:00 AM
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Both lines ARE cold. PJMax said the thin line should be warm, not cold. That's what caused the confusion.

The return and suction lines outside indicate good operation as they are both indeed cold to the touch, as opposed to just cool.

The problem is inside - the warm and humid air is not being sucked efficiently even though the air coming out of the vents is cold. So I'm left with the conclusion that it's the evap that needs cleaning along with a proper vacuum to get rid of all excess moisture and air trapped in the system.

I just want the "wet gym socks syndrome" gone from my room. Not to mention the additional load being put on the AC, particularly the compressor. My wallet too, now that I think about it!

On the lookout for a good AC technician so he can do the required service job properly.
 
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Old 05-04-16, 11:03 AM
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My mistake... I thought this was a standard split system.
 
 

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