2 years before window a.c. units trip circuit breakers?
I have a 100-year-old house in Chicago, 3 floors, and given the economy and the length of the winters, I've held off on installing central A.C. I use one window unit to cool each floor. One is on a dedicated 15-amp circuits (nothing else is connected). I get about two years out of the units before they start to trip the circuit breakers (the second and the third, both on shared 15-amp circuits, are fine). I tried having a local repair company fix one unit; they replaced a part and the unit lasted a year before the same thing happened. I've tried units from 8,000 to 12,000 btus, all with a draw under 12 amps. The same thing keeps occurring. Should I treat these things as disposables after two years? I'm hot; unit worked fine last summer, andis now tripping breaker.