Hey fellas,
Here goes another AC issue. Let's see if we can figure this one out...

Symptoms: trying to cool the house, AC recently started blowing warm air into the house instead of cold.

Troubleshooting:
- thermostat is working
- air filter is clean
- condenser line to the outside is cleaned with a wet vac
- no circuit breakers are tripped, the motor is running on the outside unit, but cuts out every few mins for half a second and restarts (strange)
- the outside unit fan is pushing out cool air, not hot
- checked the capacitor, it's good
- checked the wires going into the compressor, none of the 3 are shorted to the ground, each lead has continuity to another; did not get to the compressor itself
- regarding the two pipes coming out of the outside unit, the skinny one is around room temp, the fatter insulated one is the same (not wet and cold)

is this a sign of not enough freon or refrigerant or a faulty motor? any other advice?

 

Are you sure the compressor is running? You stated the capacitor is good. How did you test it? Do you have a dual run capacitor or two separate capacitors; one for the condenser fan motor and one for the compressor? Do you see the coil iced up? Need to use a multimeter to ensure you are getting the required voltages into and out of the contactor.

Based on the fact the suction line doesn't feel cold, it sounds like the compressor is not running. Hopefully it will be something as simple as a run capacitor for the compressor.

Here is a diagram that shows the basic testing at the contactor.

 

Thanks for your reply! Sorry, I'm a bit new to this. How do I check the compressor is running? Just buzzing?
My capacitor is dual-run, I believe (3 prongs - C, FAN, HERM).
I do not see anything iced up.
What is the contactor?

 

I edited my last post and included a contactor photo with test points and required voltages. A contactor is a relay that has incoming 240V and transfers it out to the compressor and condenser fan when the thermostat calls for cool. You stated the run capacitor is good. How did you test it? The easiest method to tell if a compressor is running is to feel the suction line coming out of the condenser. It will be the larger of the copper pipes and should have insulation on it. If the compressor is running and the system is operating properly the suction line should feel icy cold like a cold beverage can.

If you have a dual run capacitor then it handles both the condenser fan motor and the compressor. Many times only half the capacitor will fail and cause either the fan or compressor to quit working depending on which side failed.

 

Thanks for offering help!
All the voltages on the contactor are ok (T1-T2 is 240V, L1-L2 is 240V, 2 wires from the thermostat measure 24V when cooling).
I measured my capacitor with a DMM also. It's rated 55+5, and I measured 55uF C-HREM, 5uF C-FAN.
The suction line does not feel icy.
Here's a pic of my setup:

 

All of your voltages are right on. Is your evaporator coil inside clean? Have you rinsed the condenser coil this season? At this point, you will need a clamp meter to test how many amps the compressor is drawing. It could be a low refrigerant issue. For that, gauges will have to be connected to measure pressures and temperatures taken. Do you see any areas inside the condenser that appear oily?

To better assist you please post the make/model of your condenser.

 

Just to keep the thread updated:
- the coils inside and out are clean
- I did not find any oily leaks
- I don't have a clamp meter, so I'm unable to check the current drawn by compressor for now

Attaching make and model of condenser:

 

You need to find out if the compressor was running before do anything else.

 

Please post a photo of your compressor.

 

Here's the picture of the compressor:

 

Not looking good! Without physically being there, it is impossible to tell the actual condition of the compressor. Obviously, it has been overheating and probably shutting off on thermal overload. That would explain the no cooling condition you have been experiencing. That compressor should have a warranty. I suggest you contact a local Amana dealer to have them come out and look at your unit. Make sure you turn off power to the unit. Here is a link to a spec sheet for your unit. On page 1 it states the compressor has a lifetime warranty: http://johnstonesupply9.com/TechDocs...r/RCE_SPEC.pdf

Of course, it depends when the unit was installed as warranty terms change from year to year. From the serial number it looks like your condenser is around 13 years old. Hopefully, you had the lifetime warranty in effect when it was installed.

 

Unfortunately since I'm not the original home owner and don't have the original AC purchase documentation, the compressor is not covered by warranty.

I assume replacing this sucker is pretty expensive. Is this a situation where people replace the whole system? Mine is 13 years old this year. Any more advice?

 

That is unfortunate. Hopefully, the compressor is still good. The compressor windings can be ohmed out to check it. Maybe it is just low on refrigerant. Being 13 years it is getting up in age.

 

OHM'ing the compressor I got 2.0, 1.4, and 0.6

 

I replied in your other post. You need to check each winding to see if it is shorted to ground.

 

Keep in mind that the tests you performed were basic field tests. There are others that can be performed. Here is a link to a service manual for your system: http://johnstonesupply9.com/TechDocs...VICE%20MAN.PDF

Compressor info starts on page 185 and wiring diagram is on page 207.