not cool enough

I have 2 ac units in my home. one upstairs, one downstairs,
two air handlers, each installed in two different attic spaces. I live in NE Georgia and it has been over 90 for the past 10 days in a row, my thermostat is set at 77 degrees and my inside air temp hasn't dipped under 81 all day. My upstairs unit is smaller and is working just fine. I have recently changed filters (correctly)and that seems to be when i noticed the downstairs unit not getting cold enough. I am at a loss of what to do now. I turned the unit off the other night and it seemed to help the next morning. But when the heat of the day is going, the indoor temp rises ever so slowly. the unit is blowing cool air but not very cool at all.

what should i check.

 

Check a couple of items and post back here: 1. what is the temp split between the room temp and the cold air from the vent ? 2. Go outside, hand feel the 2 pipes (large and small), let us know if they are cold, warm, little warm, or hot ...(You can compare them with your good A/C unit to see if they are any different.)

 

Is the exhaust air from the condenser HOT, or just somewhat warm. Should be the former.

 

the air coming from the top the units outside are only just warm. not very hot at all. What am i checking for there? Is hot better than warm? Both of my units are the same!

1. all of my pipes outside are insulated and i cannot tell if the pipes are cold, cool or hot.

2. I have no way to measure the air temp coming from my registers. I will effort a thermometer. what is the bet way to check that? just a regular thermometer to measure ambient temperature. Just put it by the register?

 

then tear off a piece of insulation so you can check the pipes. or just call a tech

 

i will tear off the insulation. I dont want to call a tech for him just to tell me everything is fine. That costs money that I dont have. Also I have three "pipes" going into the unit. One very skinny inside of a clear tube. One larger pipe wrapped in black insulation, and a Grey hose. which ones do what? What temperature should they be. What temperature should the air from the condensor be as it is blown from the top? Hot? warm?

 

If the air is only warm, you DO have a problem. The system is not removing the interior heat. Now to ascertain why. A tech will probably find the freon charge is low (most likely) but you need to know why its low. Freon doesn't get used up. Its a sealed system. If pressures are low, there's probably a leak...could be a connection, leaky evap coil, you name it. You could also have a clogged evap coil, dust getting past the filter. Meanwhile your utility bill is gonna be high because the compressor is running longer.

 

OK, here is what you want to see: 1. the large black insulated pipe should be real cold and sweaty. 2.The small copper (uninsulated) pipe should be warm to just a little hot. Do not touch the other gray pipe, that one is your electrical wire. do not touch the skinny one, that is the T-state control wire. 3. the air blow out of your condenser should be about 10-12 degrees higher than the outside temperature. 4. the inside register's cool air should be at least 16 degrees lower then your room temperatue at that time, just put a regular thermometer right outside of the register vent to measure the air temp.. Good luck to you.