What would cause a blown fuse on home A/C unit

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  #1  
Old 08-12-05, 10:19 PM
jim7485
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What would cause a blown fuse on home A/C unit

I have a couple of 50 amp fuses in a box near the exterior A/C unit. They blew the other day and again this evening. What would cause this? It has been a hot summer, but relatively cool the past few days. Any advice?

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jim-
 
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  #2  
Old 08-12-05, 10:51 PM
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Are they fuses, or circuit breakers?

In either case, they usually blow (trip) due to overload. Is the A/C the only thing running on these fuses (breakers)? If so, I suggest you call an A/C repairman to check out the A/C first.
 
  #3  
Old 08-12-05, 11:22 PM
jim7485
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These are fuses dedicated to the outside A/C unit, about the size of my thumb. I was told that perhaps the capacitor has gone bad, causing excess load. Any thoughts on that?

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jim-
 
  #4  
Old 08-13-05, 11:05 AM
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Join Date: Feb 2002
Location: port chester n y
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A defective starting capacitor, which is connected in 'series" with the Starting-winding, will result in a starting-failure and the Line-current to the motor will be the "locked-rotor current" of the motor which is 300% X the normal running/full-load current.
The circuit is designed so that excessive current will cause the over-current protective device- fuse or C-B- to open the circuit and isolate the motor.

Good Luck & Enjoy the Experience!!!!!!!!
 
  #5  
Old 08-13-05, 04:33 PM
jim7485
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With the help of a very good H&C guy, I think I figured this out. The unit was fairly dirty, with leaves inside and quite a bit of debris outside. We get alot of cottonwood 'snow' in the summer. This stuff covered the back end of my AC unit. I sprayed Simple Green on the coils, in and out then hosed the unit off from the inside. The capacitor tested fine. So for a $3 bottle of cleaner, my problem is solved. We'll see if she continues to operate, but I think it was overheating. Also, I was told to tighten all the electrical connections. The set screws inside the exterior fuse box were no more than finger tight. The H&C guy thought this could be an issue too.

jim-
 
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