Home AC Seems Dead!

[Russ Filtz]

Yes, I still need AC as this is Florida! Last year my compressor went out and replaced that. Idiot replaced it with a size too small and my system always seemed to be cycling on/off. Well now the whole system seems dead. Unlike last time where my evap fan worked and you could hear the compressor straining to start before popping the breaker. Now EVERYTHING is dead. No evap fan running, all breakers seem fine, no sound at all from the compressor area when I turn the system on. I did notice the outside of the evaporator inside the house seems really cold to the touch. Could it have frozen up? Maybe the evap fan went causing the freeze? Would that cause the entire system not to even try to start? Even putting the interior fan to "ON' instead of auto does nothing. Also noticed some ice buildup on the pipe connection right at the compressor outside.

I did just replace the air filters which were really dirty with some high efficiency ones (800 rating). Maybe these are too tight causing lower airflow and freezup? HELP!!! Hotter in the house right now than outside.

[Phil Thien]

I did just replace the air filters which were really dirty with some high efficiency ones (800 rating). Maybe these are too tight causing lower airflow and freezup? HELP!!! Hotter in the house right now than outside.

That would be my guess.

Are there fuses inside the a disconnect at the compressor? I'd check those.

Also, there are anti-slugging devices which can be installed between the compressor and the coil. They prevent damage to the motor from an overcharged system. And the pros here will certainly correct me if I'm wrong, but I think they'd also prevent damage to the motor in a case where the filters plug and there is no airflow over the coil.

[Russ Filtz]

Pulled the covers off the air handler. Well the evap coils are half frozen, bottom up. The drip tray at the bottom is almost solid ice. Got fans running to melt it. Hopefully it didn't damage anything? There are no fuses at the compressor, just a stab in cutoff switch. There's a breaker at the air handler, but that wasn't popped.

[Jerome Stanek]

Check behind the stab in my daughters has fuses that you have to take the front panel off the disconnect to get to

[Russ Filtz]

Got the coils melted out, not sure about the lines themselves. Tried to restart the system but just hear a click and hum from the AH blower motor. Compressor side stays completely dead. I'm thinking AH start Cap or motor problem? Or possibly just low freon? But why would the fan even try to start at that point?

[David Larsen]

Would cycling on and off often mean it is undersized? I would think that if it were undersized then it would run constantly just trying to keep up. If it is oversized then it runs for a few minutes and puts a "blast" of cool air into the structure and shuts off as soon as it satisfies the thermostat. Add in poor windows and insulation and your structure will not hold any of the cool air in or keep any of the hot air out so the AC fires up again a short while later trying to again satisfy the thermostat. An oversized system does very little to remove humidity because it doesn't run long enough to remove the humidity from the conditioned air. That is why you are usually better off with it being a bit undersized rather than oversized.

[Dan Hintz]

Did they over-pressurize the system? Also sounds like it's time to replace the cap...

[Eric Gustafson]

If the coils were frozen, your compressor motor was running. Chances are, it is okay. Once the evap coils are completely thawed, check to ensure the the drainage is not plugged. You might be OK.

[Mike Henderson]

Usually, frozen coils mean that the refrigerant is low. But if you blocked the air flow, you'd probably get the same effect. In my experience, once the ice melts, the system starts up again, but it's possible there's more wrong. If it freezes up again, I'd definitely check the refrigerant level (the pressure while the system is running). And get someone to find the leak. It'll just go down again if you don't find the leak.

Mike

[Russ Filtz]

Freon was OK. Froze up because my blower motor cap fizzled (which was my initial thought as the cap's case looked bulged a bit). Compressor kept running with no air flow over evap unit = freezing. So I defrosted everything and the service guy replaced the cap and all is well. He said if you are low on freon and it freezes up continuously it is also hard on the compressor and can cause it to overheat and lock up. So basically I got off on the cheapest possible problem. $135 including the service call & parts install.