Air conditioner problem

[farmland1212]

Hello, I turned on my A/C the other day for the first time of the year and I notice that after about and hour of running my lights in the house started to dim off and on and just kept doing that over and over. So I went to the window by the ac unit and the top fan was not turning and the compressor just kept humming for about 2 seconds and the stopping. I went out to the A/c unit and if I spin the fan motor to give it a boost it tries to spin but will not and the compressor just keeps trying to turn on. Do I need a new fan motor or is there a bigger problem????


P.S. does the compressor know that the fan is not working that is why it won't turn on? the serial number off of the A/C unit is rubbed off,, but the one on the furnace is
Serial # 940935980
Model # DGAT070BDC

Hope you can help
Matt

[Robert]

Hi Matt,

Sure would save people lots of $$$$$ if the compressor knew that, but unfortunately it doesn't.


Look where the wiring conduit enters unit, just above that or in same area is the controls panel.

Remove that and see if the middle bar on the contactor is pulling in ?


Also, look at the small fan run capacitor or maybe you have just one dual cap and see if it looks swollen, bulging or leaking.


Could be a bad contactor, bad run capacitor or a bad condensing fan motor.



Thanks for inquiring,
Robert

[farmland1212]

Well, I went out and checked what u told me and the contactor, is working, and the run capacitor looks fine. I want to think that it is the condensing fan motor, but that still does not explain why the compressor won't stay on. Any more Ideas or should I just try a fan motor????

Thanks
Matt

[Robert]

Hi Matt,


Can you test to see if the fan motor is getting full power ?


IF the fan motor has not been running, compressor would continue to run until it got hot and if this is the case, it is out on internal overload.


If it is getting full power, then it is either bad or the run capacitor is bad.


If you spin the blades and it won't kick on and run, probably a bad motor.


I wouldn't replace until I knew for sure by testing as stated.


Will need to replace run cap for fan with a new motor also.


Will need info off of the motor to give price quote on new motor and run cap if needed.



Thanks,
Robert

[farmland1212]

Hey Robert, thanks for all of your help so far!! I went and tested everything and it seems like I get 230v out of everything,, however when I test the run capacitor I get 230v out of two of the of three posts on the top of the run capacitor..I have 230v on the red and brown wire but nothing on the orange wire. also when the compressor tries to run the volts drop to about 200v.
let me know what you think



Thanks for all of the help
Matt

[Robert]

Hi Matt,

So you have full 230vac coming off the contactor to compressor and fan motor and neither one will start up and run ?


Because of cost of those parts, may be best to get a Tech out to diagnose it correctly and save an unneeded part being bought.


Thanks,
Robert