Gas and Oil Home Heating Furnaces - Outside AC unit still hibernating!

Hello Everyone,

Tried to fire up the AC as it was about 80 degrees here in Austin yesterday and of course, the first time homeowner curse follows me again! All is OK with inside the house stuff (thermo, blower fan, relay) however outside unit just emits a loud BUZZZZZ. I assume this is probably the contactor grid? That's where it seems to be coming from. I don't think it matters, but it's a Goodman unit...I'm thinking all electrical schematics are going to be pretty similar from brand to brand. The question is.....how do I test the circuit ? What happens in the circuit? The contactor looks like it's pulling in correctly when the signal hits...maybe not far enough? I tried to press it further in to no avail. Also, how worried should I be about HI voltage here? The unit cools a 1650 SF house.

(it's kinda weird that it still buzzes after I pull the power connector blades.....is it pulling power from capacitor or something?)

thanks a bunch!

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Is because your transformer is inside,trying to energize the contactor.Turning the switch off outside does not kill the 24volt control circuit.TURN OFF HIGH VOLTAGE!!!!!!!!!!!! and control power(other breakers) until buzzzzzzzzz stops.Contactor will de-energize.Push contactor in and out to make sure it moves with ease.MAKE SURE that over the winter that bugs or spiders have not made a nest between contacts.PDF

so the contactor is energized by a 24 volt AC signal? And this puts a high voltage (110?) to the fan? I suppose I should check to continuity between high voltage source wires and fan wires with contactor is out and in....then maybe I will see the connection being made....I'll be testing in an hour! I'll let ya'll know what I see (with pics if needed).

Chris

Forget my advice, PDF's is a lot better!!

Just to let you know, most central A/C units run on 220V, not 110V.

condenser fan coming on when your turn the A/C on?

After cleaning up the contactor good with spray electrical solvent and working the contactors in and out, everything worked properly....apparently...a big ole butterfly larvae want to kill itself by electrocution. With no contactor (buzzing was contactor trying to close and freaking out I think) there was no power to fan or condensor....they both pull power from output side of contactor....


thanks for the help!

Chris

one the guys at work it was a spider nest in your contactor.Those darn butterflies cost me 5$...Good troubleshooting Chris.PDF

Well...that worked pretty good for about a week or two then problem 2 came about! The fan motor or condensor wouldn't come on...but the contactor was putting the voltage through properly thanks to my previous cleanup.....turns out the capacitor now looks like a coke can that was left in the freezer! All terminal connections are open on it so I'll be replacing it tomorrow.

why did I stop renting again??

hehe

:D