Tip & How-To about Heating & Cooling

Replacing a condenser fan in centralized A/C

On of the common problem with centralized A/C unit is a bad condenser fan. I have known people who called an ac technician to fix their ac because of a bad condenser fan and suggested replacing the whole unit! Costing them a lot of money when all it needed was a 50 dollars condenser fan! If the condenser fan do not run or it runs only when you give it a push, it'sbad. You will also notice that it is vey hot. When replacing a condenser fan you may want to replace the starting capacitor too. Replacing a condenser fan is not very hard, just make sure that the power to the ac unit is turned off at the breaker box. Confirm that the wires are not live by using a meter or an ac tester. The fan motor are held with brakets sometimes just screws. Most fan you can buy that has reversible rotation by just reversing the plug. Make sure it is blowing upwards. If not reverse the rotation. So if you notice that the unit is not putting out cold enough air and you went outside and noticed the compressor running but not the fan, turn off the AC right away and do not use it untill the fan is replaced. Running the unit with a defective fan can damage the compressor caused by overheating.

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Everytime my central air unit kicks on my circuit breaker trips. It didn't do this last year or even earlier this year


A circuit breaker 'tripping' everytime the AC unit kicks on 'most always' indicates a direct short (somewhere in the condensing unit), although it is possible that the breaker itself is bad - (but not likely).

Usually the cause of this 'short' will be - either the condenser motor in the condensing unit (outside unit) or the compressor - also in the condensing unit.

If you're mechanically inclined - and "very careful" around electricity - there is a fairly simple way to find out which component is causing the short.

Step 1 - Make sure the condensing unit (outside unit) is completely disconnected (electrically) , i.e. pull the fuses/turn off circuit breaker on outside unit and turn off thermostat.

Step 2 - disconnect the condenser motor (this is the outside fan motor). Note: when you disconnect the wires of the condenser motor "be sure" you mark/write their location, and wrap them in electric tape.

Step 3 - start the AC unit. If the breaker trips again you can pretty much rest assured it's the compressor that is shorted.

To prove it (without a doubt) - go to next step.

Step 4 - "be sure circuit breaker and thermostat is turned off" - and - 'reconnect' the condenser motor - and - then disconnect the compressor wires (mark wires and tape them).

Step 5 - Start AC.

If breaker doesn't trip - you know it's the compressor that is shorted.

If breaker 'does' trip again - then it's possible the breaker itself is bad (not likely) or there is a 'short' in the condensing unit's "wiring" somewhere (not likely).

My guess is that either the condenser motor or compressor is shorted.

Hope this helps.

Good Luck!

Jun 10, 2010 | Heating & Cooling

1 Answer

whirlpool central ac stopped blowing air, cool or fan only. compressor outside running and attic unit on but no air. Solution??


If you are refering to the indoor fan that is not running, but that the outdoor condenser is operating, the next place to check is the circuit board in the air handler, this is the control for the fan motor. the relay may be bad that actuates the fan circuit. if the relay is bad there will be no power to the fan motor. If you have power to the fan motor then the motor is bad and the motor and capacitor should be replaced.

Jul 20, 2009 | Heating & Cooling

5 Answers

AC unit runs inside but not outside! help


check breaker thermostat set cooling auto call for service.allso get it cleaned both coils.. Tom

Jun 19, 2009 | Ruud UAKA042 Air Conditioner

1 Answer

condensate pump on humidifer/ac


To me it sounds like a tube is plugged so where, It also might be the switch is going bad on this unit.

Dec 09, 2008 | Plumbing

4 Answers

central ac blowing hot air outside fan not moving but making a noise


This is nothing but an either or -or ! First, make the thermostat calls for cool, there are suppose to be 2- noise outside, the fan motor and the compressor (and if a old system,a humming noise which is the contactor coil which picks up the main 240-volts).. hurry up and take a stick or something and turn the fan blades, if it picks up speed and run, then its the capicator. If not then the fan motor is bad.! (BOTTOM LINE)!

Jun 09, 2008 | Heating & Cooling

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