Air Conditioning - Outside unit (compressor/fan) keeps running after inside unit shuts-off

The outside unit doesn't turn-off when the thermostat turns-off the inside unit. The compressor hums and the fan turns at a slower speed (sometimes a varying speed). Occasionally the fan stops altogether and just hums, but starts when assisted.

Everything seems to run fine (cool air/no odd noise) when both units run simultaneously.

I have noticed the small copper tubing is sometimes warm & sometimes very hot to the touch. No iceing on the larger tubing.

I have liberally used a water-hose to wash the dirt from the coils and the bottom of the unit. My dogs had covered 1/2 way up one side and the bottom with dirt.

I've been useing the main breaker to turn on/off the outside unit for the past 3 days. Can this compound the damage? It will be early next week before a technician can come diagnose the problem.

Any help/suggestions will be GREATLY APPRECIATED.

Thanks, Ken (Lori's husband)

bump for a little advice.

I would say there is a 99%+ probability the contactor is stuck (contacts welded). Inexpensive & easy to replace if you are not afraid of working with wiring.

Thanks for the reply Grady, it would be wonderful if I could fix it tomorrow.

I have wired things in the past. If it is a simple disconnect install and rewire it shouldn't be a problem. If it's too difficult I can have my brother help(he is an excellent mechanic.

Please describe what the contactor looks like and where it is located? Or maybe direct me to an appropriate thread?

Also, am I damaging the system by running the A/C using the breaker? Once the outside unit ran alone for about an hour before I noticed.

THanks a million GRADY!!

THIS SITE ROCKS!

I just noticed your reply said "the condenser keeps running."

It is the outside unit that stays on continuously, unless I throw the breaker. Is that the compressor or the condenser?

Do I have my terminology backwards?

Thanks, Ken

The contactor is located inside the panel where the wires connect. It is the part (relay) where the wires from inside the house connect & supply power to the outdoor unit.

http://www.hvacoracle.com/images/Controls/burnt_contact.JPG

Here is an idea of what it will look like. Make sure the electric is OFF when you go in here and make note or take a digital picture so you get the new one wired correctly.

Mattison thanks for the reply,

Would you please look at post #5 in this thread.
I think I may have confused you and Grady..?

It is the outside unit that keeps running. Is this the compressor or the condenser?

Should I proceed with changing the contactors?

Thanks for the pic.

Ken

The outdoor unit is the condensing unit or commonly called condenser. The compressor is the big "can" (usually black) inside the condensing unit.
The indoor coil, in a cooling system is the evaporator.

As you may have noticed I'm entirely ignorant about the A/c.

However, with the assistance you've given, I'll be able to fix it myself tomorrow.
I've located the contactor and it appears to be a piece of cake to swap out.

You and Mattison have saved my wife and me from 5 more days of 101+ suffering and the cost of a service call!

Bless you both, Ken

I think I can speak for Mattison as well in saying it is our pleasure to help.
Should you run into any difficulty replacing the contactor or have any other questions with which you think we might be able to help, please don't hesitate to post your questions. Be careful & get cool.

Let us know how it turns out.