Central Air Suddenly Very Weak

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  #1  
Old 08-17-09, 10:17 PM
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Central Air Suddenly Very Weak

Hello, I have a big old KeepRite A/C unit that sits outside and normally does its job without complaining. But now I'll set the thermostat to 75 for example and the fan will blow forever trying to get to 75, but it'll never get there.

I took some insulation off the 2 freon lines going to the A/C unit outside. One should be cold and one hot, right? Well one is room temperature and the other is a very little bit cold. What do you think it could be?
 
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  #2  
Old 08-18-09, 04:02 AM
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Compressor not running or low on refrigerant, has the air flow become weak all of a sudden?
 
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Old 08-19-09, 07:52 AM
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Thanks for the reply! The air flow is the same as before, just alot less cold . What else can I do to diagnose this problem?
 
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Old 08-19-09, 08:14 AM
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What else can I do to diagnose this problem?
Verify that the compressor is running, if it is you will more then likely have to call an HVAC tech.
 
  #5  
Old 08-19-09, 06:18 PM
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Hmm well it sounds like either way I will have to call an HVAC tech, if the compressor is running or not. I'm afraid he'll try to take me for a ride and tell me I need a whole new system, even if it only needs a recharge
 
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Old 08-20-09, 04:26 AM
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Its not hard to tell if the compresor is running, you should be able to hear it. Do you have a meter and know how to use it?
 
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Old 08-20-09, 08:48 AM
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Thank you for your continued support, dun11! I went outside to the big ol' box with the fan on it to look for the compressor since I assumed that's where it would be and its empty inside! Just some cooling fins (where the freon must run through?) and a big cooling fan. Judging by where the freon lines run to, it looks like my compressor sits on top of the furnace inside of the house. I'll try to take the panel off of the area where I assume the compressor, but until then I am curious about your "meter" question. Do you mean a multimeter? I do have one, and this seems like a good time to take it out of the packaging!
 
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Old 08-20-09, 09:15 AM
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The compressor is outside....its just a round can looking thing with a few wires and some tubing running to it. Its inside the same enclosure as the fins and fan. The lines running to the top of your furnace is where the evaporator coils are. Thats where the cool air is produced.
 
  #9  
Old 08-20-09, 09:18 AM
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The compressor is in the outddoor unit you just can't see it, its in the middle of those coils. Take off the panel on the outdoor unit where you see the wires going in, that should get you to the start componants. Yes, I mean a multimeter.

Once you get to the start componants check the contactor for 240v incoming power. With the stat on and calling for cooling you should have 24v at the coil of the contactor.
The contactor should pull in (chk for 240v at load side of contactor) and the comp should start.

If all of these voltage readings are present and comp does not start need to chk the capacitor.

That should keep you busy for a little while, let me know what you find.
 
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Old 08-20-09, 10:13 AM
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Originally Posted by dun11 View Post
Once you get to the start componants check the contactor for 240v incoming power. With the stat on and calling for cooling you should have 24v at the coil of the contactor.

The contactor should pull in (chk for 240v at load side of contactor) and the comp should start.

If all of these voltage readings are present and comp does not start need to chk the capacitor.

That should keep you busy for a little while, let me know what you find.
Ok, I'll start checking everything for voltages. Not exactly sure what a "contactor" or "capacitor" is but I'm sure I'll figure it out once I get there . Will report back with voltages!

EDIT: Looks like I need to head to the hardware store to buy an adapter to get the screws off the side of the A/C unit, will try again tomorrow! In the meantime, it seems like the freon lines are really cold near the compressor and then room temperature near the evaporator coils on top of the furnace, even though they are insulated the whole way. Also, I tried to "hear" if the compressor is on, but its hard to tell with that big noisy fan running right beside it!
 

Last edited by esca85; 08-20-09 at 10:56 AM.
  #11  
Old 08-20-09, 02:30 PM
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looks like Dun11 is a pro on A/C, I do have similar problem as described by esca85, do you think it's time to change compressor? or I can clean and fix the old compressor? or other cheaper way to fix the problem
 
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