So, these are the symptoms:

1] The big fan outside is taking a lot longer to start.
2] Within 2 minutes of start-up and cooling, it makes a growling/ rattling sound and
3] The power switch to start the AC trips automatically and the whole unit shuts down.

The problem started this morning, after a power outage, when we heard that electricians were repairing connections somewhere in the city.
Until then the AC was running fine. What could be the problem.

  • 1
    Was the unit turned off then back on rapidly? What is making a growling/rattling sound? "The power switch to start the AC", do you mean the circuit breaker? – Tester101 Jun 30 '16 at 11:29
  • @Tester101: The power switch is a North West Single Phase Motor Starter. The big outer fan of the cooling unit. is making a growling sound just prior to the auto cut. – user55827 Jun 30 '16 at 11:44
  • Let the AC system "rest" for an hour to ensure there's no fluid back-pressure anywhere which happened when the power outage hit. – Carl Witthoft Jun 30 '16 at 13:57

I'd start by checking the start capacitor for the fan motor. If that's starting to go bad, the motor could be drawing high current for too long while trying to start.

| improve this answer | |
  • A spike could have punched the dielectric especially on an older one.+ – Ed Beal Jun 30 '16 at 15:56

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