Just move into a home with central A/C. I was trying to test it tonight and it does not come on.Set to cool and the A/C indicator on my control lights. The compressor does not come on nor the fan in the housing. The outside temp here is 40-45 degrees.is there a switch that control the turn on other than the interior control??Does the outside temp have to be higher than the inside temp to activate the system???I have verified power to the machine.


Thanks

Outside temp makes no difference to the unit, it will come on depending on your temp settings.  I guess by checking power, you made sure the breaker switch for the AC was on?  Is this a new home or old, if new the thermostat could be wired wrong.  There shouldn't be any other switch that I know of to turn it on.
Bill3508

Make sure there is power to BOTH the AC unit and the furnace/air handler. If there is one, does the furnace work in "heat" mode? If someone switches the AC on do you hear a click from a relay in the furnace or AC unit?

Do you have any sort of "home warrenty"?

Don't be afraid to call an AC guy either. A coworker of mine went for years without his AC because it blew breakers and he figured the compressor burned out, and it would cost $$$$. Turned out to be a capacitor that came loose and shorted to the frame. The guy fixed it for a couple bucks.

This is a home i just bought. the ac unit is about 7 years old according to the date on it.The previous owners stated that it worked last summer. The furnace works just fine. All the breakers are set on.

time to call a tech I guess

Thanks for the help guys

You might want to first check the small control wires at the thermostat, furnace, and AC unit to see if any of the connections are loose or coroded. Shut off power first, of course. Could be something simple like that. It might be worthwhile to try a different thermostat too.

If it's not the thermostat or wiring, it may be a bad control board in the furnace. You may want to take a peek at it too see if there are any components or circuit traces that appear or smell burnt up. I've seen that before.

Most importantly, if the tech tries to sell you a new AC unit, be sure to get a second opinion.