air conditioner - http://www.hvacmechanic.com/ Forums
Original message
| Red_bird
 |  "air conditioner"
, posted Thu 5 Jun 09:25  
outside unit wont kick on no noise coming from it fuses on inside are good,furnace fan kicks on but unit outside does nothing!!!is there a fuse outside in the metal box or is that just to pull out to make sure no elec is going to it while you work on it . the thing is black has a handle so you can pull out and sorta looks like along plug can that go bad?
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Replies:
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| Freon
| "Re(1):air conditioner" , posted Thu 5 Jun 16:13
Most likely the thing with the black handle is the disconnect and is to remove the 240 volt power to the unit. Double check but I don't think it is fused.
Pull the disconnect so there is no power to the outdoor condenser unit.Look to see where the power chord enters the condenser unit. Remove the cover to the electrical box on the condenser. Call for cooling at the thermostat. Now go out and listen very carefully at the electrical connection box on the condenser. You should hear a slight hum of the contactor trying to energize the condenser. If it is really dead silence, then you may have lost the 24 volts going to the contactor coil. Check the small wire coming from the house and entering the condenser electrical box. Be sure there are no breaks. If the wire looks good, check for 24 volts AC at the contactor coil. If present, get a new contactor.
If you hear a hum then the contactor coil would appear okay and possibly the contactor points are bad. But I would verify 240 volts on the line side of the contactor before doing anything else. If you're uncertain about measuring voltage, this is not the time to learn... call for help.
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| | lakefanatic
| "Re(2):air conditioner" , posted Thu 5 Jun 18:32
I am experiencing a similiar problem. Checked the voltage and it's ok and pushed in on the contactor point button while the unit was off. When I turned down tstat after testing, heard a "hum" and a few minutes later the air kicked on. So are the contactor points bad? Is this something an novice electrician can purchase and replace?
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| | Freon
| "Re(3):air conditioner" , posted Thu 5 Jun 19:25
Pull the disconnect to the condenser. Remember, this is 240 volts so you can kill yourself if not careful. With the disconnect pulled, open the electrical box of the condenser. Now look at the contactor points. Signs of blackness(soot from arcing) or bad (pitted) contact points means you might need to replace it.
But to be sure you need to measure the voltage when all is alive on the load side of the contactor. Replacing a contactor IF (emphasis on if) you know that's the problem is easy as long as you pull the disconnect AND tirn off power to the air handler/furnace. Be sure to make every wire you disconnect so you know how to reconnect it.
If in doubt, ask for help from a friend or someone in the business you trust.
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