Hi I have a 10 year old central AC and it started to do this split second double start, then it runs just fine cooling the house. What do you think it is? Mike

Do you mean on, off, and instantly back on? Is it the blower, compressor, or both? Could be the relay controlling one or the other chattering. Clean all the connections to the coil. If that doesn't do it, check the voltage at the coil. If it is 24-25 volts, the relay may be bad. If it is less than 24 volts, the transformer may be bad.

Hi the split sec. start was caused by the mecury bouncing in the thermostat