This central air unit was installed with new Lennox G51 furnace in December. Had to wait for the warm weather to test air. This untit has a hard start up, sounding like a electrical surge in the basement where the lines come in. Outside, in addition to the fan noise, a buzzing noise can be heard. This sound radiates inside into the basement and is louder down there. The contractor seems to think it is normal. I say no way.

Any help out there?

Thanks