AC coil not getting cold enough.?

Question

The original problem was the air vents dripping from condensations.

A licensed AC man came, said my condenser freon were over charged so he discharged it and left. Since then AC wasn't blowing cold air.

I called him back, he checked again and said the level is perfect and not sure what could be the problem, so he put back 2lbs of freon and left. But still the air is no longer cold.

I open the blower unit and check the coils and noticed they are not very cold no where near 45 degree or so. I also check the attic for leaking duck system and was fine. I'm not confident about this AC man and called others, but earliest appointment is set for Wed.

Meanwhile, with AC running all day long, the temperature goes up instead going down. What could cause the coil not to reach near 45 degree when everything seem normal?

Answer 1

Bad AC man...in my Opinion.


I never seen an AC System Produce and ADD it's Own Freon.

And if You just began having this prob,,,
and nobody has worked on the system,,,,

WHERE DID the OVERCHARGE Come from???

His Gauges may be SHOWING Hi Pressure,Overcharge.

But that's a BLOCKAGE on the Hi Pressure Side,,,
Not Excess Refrigerant charge.

You get the Sweaty Evap Core becaus it's UNDERCOOLING.

Undercooling + Hi PSI on HI Pressure Side + "Normal" on LOW Pressure side = Restriction between Compressor and Evap Core.

It LOOKS Overcharged cuz it's
"normal on LOW side" while HI on HI Side.

Reason it's NORMAL -looking on Low Side,,,,
Even though it's STARVED and should be Excesss LOW/Hi Suction,,,,,

Is because the OUTPUT side of the Pump is RESTRICTED.

Compressor cannot suck down LOW Side,,,
cuz it's Dead-Heading against a restriction on it's outlet.

Makes for a "MIRAGE" on the pressure gauges.

If You got Hi PSI and Normal-looking Psi on LOW side,,,,
WITHOUT a cold,wet line all the way back to compressor.
Thats a Hi Side Restriction somewhere BEFORE the evap core.

Inline filter?
Expansion valve screen?
Capillary tube screen?


It's effectively same as a TINY,TINY Compressor Flow Volume,,,connected to a Huge,Giant Evap Core.

You do not get the VOLUME of Freon Expansion to cool the entire Evap Core.

All the Cooling happens in first few inches of Evap Core surface,soon as it exits the Expansion Vavle or whatever control it has.

Easier to think in terms of a Hot water radiator.

1 cup of Boiling water per Hour will NOT raise the temp of a radiator the size of a House,,,in 40* weather.

Simply Not enough Volume.

Fix the Restriction Between Compressor and Exp Valve/Orifice Tube,,,and it'll Cool.

If the Cost ain't just Stupid,,,,
It's worth having a BIG filter installed on BOTH sides of the Compressor.



Lottsa "Experts" & "Pros" disagree with that.

I'm Not a Pro or an Expert,,,
I don't Sell AC Units to people with ,,,
"Bad Compressors".

So I just have ZERO Skill at showing folks how those Goofy Numbers on the gauge mean,,
"Yep,,Ol' Compressor is going Bad"

If it's pumping Hard enough to FAKE an OVERCHARGE,,,
Can't be THAT puny,,can it?


Meanwhile,,,,
You can TRY this to get it a LITTLE Colder,,,MAYBE.
Block the Airflow at your AC Filter/Return Air Intake.
Cover about 1/2 to 3/4 of it with some cardboard or whatever.

What that does is >
Reduce the Airflow across the Coil,,
Which reduces the Rate at which the Cold is swept off the Coil by Return Air.

Evap Coil Temps will drop due to the reduced airflow "warming it".

You'll get Lower Flow at your VENTS,,,but it will be COLDER.

Cheap and Easy to TRY,,,and it Usually HELPS.
***It's a TEMPORARY "TRICK" >>ONLY<<
Ya dont Ever wanna do that on a Properly Functioning system,,,to try to cheat a few extra degrees cooler outa it.

It will Freeze the Evap,,,and CAN cause damage.

It's ONLY "safe" on a Plugged-up Hi Side,,,becuase theres not enough freon flow to Freeze the Coil.

Your 2~3~4 Ton System,,,being RESTRICTED,,,is effectively only a "1/2 or 1 Ton System".
Choking the Return Air across the Coil Better Matches the system's diminished capacity.

Good Luck with it,,,,
"Next Wednesday" is normally 'bout 3 days from Sunday.
Except in June/July/August with AC Probs.
Then,,it feels like Forever.

Answer 2

Is there hot air at the condenser unit outside? If the condenser is cooler than the indoor space, it will have difficulty cooling the indoor space.

You say that the original complaint was the registers were dripping condensation...I imagine that the system was working to cool your home at that time? Have you checked the condensate lines to ensure that they are clear and the water can flow out properly? Are the indoor coils clean so that water is not getting trapped on the coil and sucked down the ductwork?

As for your current problem, as the others have written, some type of restriction in the line is most likely your culprit. A real pro will have to address this unit.

Answer 3

Ours was doing the same thing, and finally the AC man, cleared out the lines, or pipes, and 1 of them was stopped up.
That fixed it.

Answer 4

Sounds like he stole your freon and didn't replace it. ~