Posted: 5/29/2008 6:10:02 AM EDT
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OK, last night, when I got home from my walk, the AC outside unit was making odd noises. When I checked, the compressor was running, but the fan was not. It was HOT to the touch. We turned off the AC and called the repair man. The AC guy is at the house now. When they turned on the AC, the fan ran. There is frost on the copper tube. The guy thought the evaporator coil (replaced two years ago) was clogged, but checked and found it wasn't. Is the fan motor bad, is the AC just low on freon, or is this something else? 
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I don't know what brand of ac you have but the fan should run when the compressor does. If it doesn't you end up with high head pressure and eventually a blown compressor. Fan motor could be bad (intermittenly) or it could be a bad relay. Your repair man probably knows better since I'm still a rookie. 
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You have a blockage some where. First of all check the filter. Leave the unit off for a while and let the coil thaw out. If it's a heat pump turn it on heat for a bit and that will get rid of the ice faster. Make damn sure that your condensation line is open cause there's gonna be alot of water coming out of it and you dont want it in your attic if thats where your air handler is. |
He thinks the restriction may be in the compressor, due to the fan stopping. Sounds like a chicken and egg problem. Did the motor overheat and fry the compressor, or did the compressor overheat (constriction) and cause the motor to overheat? |
I do not know much about A/C systems other than having a compressor replaced a few years ago, which wasn't cheap. Has he given you the approximate cost of pulling all the refrigerant out and then recharging your system with new refrigerant? Around here the going rate for recharging a system is like $80/lb of refrigerant, and most systems take >4 pounds. |
I'm an admitted newbie to this stuff, but I don't see how an overheated compressor could fry your fan motor. I see how the fan motor going bad could cause your compressor to fry, but I can't imagine the opposite. By the way, if you have a bad compressor, have some KY jelly at the ready. My compressor replacement cost $1100, and that was just labor and refrigerant, since the compressor parts were under warranty. |
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The fan motor could be going bad. When you shut it off and by time the sevice teck arrived, the motor could cool off enough to run again. Could be as simple as a capacitor also. As far as refrigerant, hard to tell unless I was looking at it, but an outdoor (condensor) fan motor (not working) will not cause a system to freeze up in the cooling mode. That will just raise the high pressure......no air moving across the outdoor coil. |
| #1 Call another service tech. He couldn't tell you either way if your refrigerant level was correct if there was a restriction in your system. If you have frost on refrigerant lines it would help to know if it was on the suction (bigger) line or the liquid (smaller) line. If the suction line is frosting it is due to being low on refrigerant or a clogged air filter. If the frost is on the liquid line you could have a restriction there and ususally you'll find this at a filter drier. In either case your condensor fan motor (outdoor fan) would not have anything to do with frosting lines and is a seperate issue entirely. It could be a motor going bad or something as simple as the run capacitor. Refrigerant NEVER goes "bad" and also never needs to be completely removed and replaced unless there is a MAJOR compressor failure. If they need to get into your refrigerant system the old refrigerant can be romoved to fix the problem with a recovery machine and recharged right back into your system. |
I'm not one for the interweb wienie slap fest but half of the statement is wrong. There are a lot more reasons for refrigerant to go "bad" To the OP, did you get this worked out? |