Air Conditioning - Outside unit not working properly.

Hey guys. I have been reading this forum for about 2 days trying to find some info on a problem I have been having with my outside unit. I will give you a run down on what I have been seeing. This will be lengthy. Sorry in advance.

My unit is a Rheem 10 seer with a scrool (spelling?) compressor. That is what is says on the cage on the outside unit. I am not sure what size it is. It has a White-Rodgers Digital Comfort set II thermostat. Model 1F90-51. I have owned the house since November of 2006. A/C unit was manufactured in June of 99. Installed in August of 99. The only problem I have had with the unit is the condensate drain plugged up, but I quickly corrected that problem. I have changed the filter once per month since I bought the home.

My problem:
Saturday my wife came in and woke me up (I am a shift worker) at about noon. She told me the a/c unit was not cooling properly. So I got out of bed and looked at the thermostat and it read 78. The thermostat was set on 70. I started looking around. The air mover inside the house was doing fine. I touched the small cooper tube running into the inside unit and it was REALLY HOT. The big tubing was just warm. I went outside and saw that the fan was not turning. I heard the unit humming. I shut the power off to the unit and took the cover off and tried to see if I noticed anything that stuck out. I am NOT an A/C guy. The compressor was really hot. The fan blades spun very freely when I pushed on the condenser fan. I looked for a reset button for the compressor but did not find one. There is not pressure switch that I can see either. I turned the power back on and the fan kicked on but the compressor did not seem to kick on. I could not here the SWISHING sound of the freon moving and did not here the compressor doing anything. The fan ran for a short period of time then it seemed to slow down, then it stopped. I killed the power and had to go to work at about 4 pm. While at work, I looked up as much info as possible on the unit I have. That turned out to be a bust. Even though I have the model and serial number there is no info to be had. I checked the rheem site and that was a bust also. So, I looked up the info on the thermostat and it said that if you were having cooling issues, try to reset the thermostat by pulling the cover off, and removing the batteries. Effectively removing the 24 volt supply and the battery back up for about 5 minutes. I had my wife do this and at about 2130 hrs she kicked on the unit and it ran perfect. Now the unit had been off and powered down for about 5-6 hours. When I got home this morning the thermostat read 70 degrees. The unit was off. Well, before I went to bed, the unit cycled a couple of times and I really thought it was going to be ok.
At 1130 this morning, I woke up hot. I live in Mobile, Alabama so it was already about 87 outside. I checked the tstat and it was reading 75. I checked the outside unit and it was not turning. I killed the power to the unit. I tested the voltage to the contact from the tstat and it was good. 24 volts. You could also here a slight humm at the contact. I pulled the tstat cover again at swapped the inside unit to fan only. I went back outside and cleaned any debris from the coil. I checked all the wires for any loose connections. I found 1 connector on the capacitor ( it has 3 sets of connectors) loose. Not off, just loose. It fed the fan. I took it and crimped it slightly and repositioned it. It was a tight connection now. After doing all this I energized the breaker and used my fluke to test the contact for power. 240 in. I closed the contact with a screwdriver. The Fan and compressor just hummed. I had 240 out of the contact. I tried to nudge the fan but it was not going to move. I turned power off again and checked the fan. It spun freely. So, the power was off for about 1 hour. I buttoned everything up and started the unit. It ran good for about 45 minutes. I checked the tubing. The smalling tube was warm, the big tube , nice and cold. Then it repeated the same thing. The fan and compressor just stopped. I shut the power off to the unit and I am at work again. I hope it runs again tonight for my family at home. What would cause these symptoms? Any help would be appreciated.

To start, I'd replace the capacitor. You may also have a bad fan motor but try the cap first. They are inexpensive & easy to replace. Your symptoms sound like a capacitor breaking down during a run.

and was leaning in that direction. But I am no a/c guy and thought you guys may be able to give me some tips. I am a little concerned about discharging the capacitor completely.

I agree with Grady,

To discharge the capciitor, just take a screwdriver, keep your hands on the handle, and take it across the two post on the fan capcitor. Do it a couple of times.

Bad capacitor or bad condenser fan motor. This is a very common problem. I suggest you not run the unit until the problem is fixed.

The tech came out (under warranty) and replaced the fan motor and installed a new single run capacitor just for the fan. He left the old dual run capacitor for the compressor in the unit and I suppose the only wires that are connected are the ones to the compressor. It seems to be working fine.

I have a question though. If the old dual capacitor goes on the fritz, do I have to replace it with another dual run? I believe he ran a wire from the old cap to the new cap for power to the fan. Is that normal? If it is, I guess I just answered my own question.

But anyway, thanks for the help guys. I appreciate the info.

Did he just let the new capcitor lay?? If so, that's a poor workmenship!

You do not have to use both sections of a dual capacitor. But as Jay mentioned, they should be secured. If, in the future, the compressor cap needs to be replaced, a single unit may be used.

Jay11J -Did he just let the new capcitor lay?? If so, that's a poor workmenship!
05-08-07 08:10 PM


Jay...
Yea, he wrapped the top of it with electrical tape and bound a wad of wires with electrical tape and sat it in the corner of the little compartment. It did not look rea; good to me either. Thanks for the help.

Might slip a plastic wire tie over the new capacitor to something in the unit there. So it cant move around.