Condenser fan turning off for no apparent reason

[MedikDave]

I'm at a loss. This started after my fan blades broke free from the collar on the motor shaft. I replaced the blades with an identical set, and then started having issues with the motor shutting down. I replaced the 3 post capacitor, no luck. I noticed the contacts on the single pole contactor were worn, so I replaced that as well. Still no luck. 

I noticed the fan was getting very hot. So my thought was that it got damaged when the fan blade assembly broke, and was experiencing thermal shutdown. I've now bought a new fan motor and capacitor, the links to what I bought are below. My original fan motor was a GE 5KCP39GGS325S.

Capacitor - https://www.grainger.com/product/2MDV4
Fan Motor - https://www.grainger.com/product/1UME7

So, what is happening is that the fan and compressor turn on, then after about 5 minutes the fan turns off, resulting in the compressor turning off due to thermal protection. Eventually, the fan turns back on, the compressor cools off enough to turn on, and the cycle starts all over again. I don't know what else to replace. Not sure if it makes a difference, but I have been using a Nest thermostat for about 2 years. Thank you very much for assistance you can provide.

David Riley
Hotter than Hell, Texas

[BrewHobbyTech]

32 minutes ago, MedikDave said:

So, what is happening is that the fan and compressor turn on, then after about 5 minutes the fan turns off, resulting in the compressor turning off due to thermal protection. Eventually, the fan turns back on, the compressor cools off enough to turn on, and the cycle starts all over again.

A quick question......is the condenser fan motor turning in the proper direction? 

[MedikDave]

Yes.  It's pulling air up from below and blowing it out the top.

[BrewHobbyTech]

I should've added this too.......AND make sure the fan blade was put on the right way. If it was put on upside down you'll still feel it pulling air but not nearly the volume it should. And make sure the condenser is fairly clean. I'm just throwing a few obvious things out there, but it's getting late and I've had a crappy day.....and put in about 13 hours already......my brain is fried right now........just throwing out a few ideas bro. 

[alamo1718]

Is it a heat pump? The defrost board controls the outdoor fan operation on a heat pump.

Also,  5KCP39GGS325S shows as a 1/3 HP. The grainger link sent me to a 1/6HP motor.If the links are correct, its the wrong size motor.  The other link sent me to a fan only cap. The 3 post capacitor is a dual cap for the fan and compressor. Did they sell you the right cap for the motor they sold you.

And I second checking the fan blade correct installation from brewhobbytech. 

[MedikDave]

Dangit, I just noticed the HP difference.  The Grainger website showed that as a compatible motor, so that's what I ordered. I may have clicked 1/6 by accident. I'm using the two post capacitor because the motor has 4 wires to use a dedicated capacitor vs the 3 post that is shared with the compressor.  The old motor only had 3 wires.

Someone on another forum suggested that the fan blades I bought were the wrong pitch, and are causing the motor to work too hard and shut down.  Looking at my current blades, they look like a lot more than OEM, which I now know is 24 degrees. 

I still have the old motor.  If the fan blades have been the issue all along, then I'll order the oem blades and try them with the old motor.  Hopefully I can bring the motor back to Grainger, but I think it's going to be a "lesson learned".  Thanks for your help.

[BrewHobbyTech]

The difference between a 1/6 and 1/5 HP motor isn't a lot......and probably......or at least shouldn't cause the problem you're having........BUT.......if you're using a lower HP motor, AND you're blades are a far enough percentage off pitch/angle.......it COULD cause the problem you're having, AND make sure you didn't put it on backward/upside down. Again.....I'm just looking at the most obvious causes that I can think of off the top of my head.......and remember......my brain is fried.......so don't quote me(because I'll deny ever saying it, LOL), and take anything I say tonight with a grain of salt.....and/or a shot of tequillla.....and a beer.....whatever works...... 

Hey alamo....thanks for agreeing with something I said. I don't mind being a lone wolf but it's always good to have another tech actually agree with a possibility of what I said, because that's what it is.....it's a possibility.......at least I'm not totally nuts.........thanks bro......I'll send ya a brewski..........  

 

 

 

 

[MedikDave]

It's actually a difference between a 1/3 and 1/6 HP motor.  I accidentally bought a 1/6 to replace the 1/3.  Either way, I ordered an OEM fan blade from RepairClinic that should arrive tomorrow. The only thing keeping me from total frustration is knowing that even if I bought everything in vain, and the fan blades were the problem all along, it's still cheaper than calling out a repair company. Bless you all for helping out us stubborn DIYers.  

DR

[alamo1718]

Your welcome brewhobbytech. You made a good point. I now mark my blades on the bottom before I pull the blades. That way when I put them in upside down again, its easy to see why the damn thing wont work this time.  . 

The unbalanced blades probably wore out the bearings in the old motor. You will probably need a new proper size motor too. The blade pitch can increase the amp draw and cause the motor to go out on thermal. So can putting the blades on upside down. The test is to use an Amp Clamp tester and test the Amp draw of the MOTOR after installation. The max Amp draw is written on the motor. Its usually well under 2Amp. It should never be over that number. If it is, buy a new motor. 

Please be very careful with Amp tests, they're done on energized equipment and can kill you. With the fan motor running, the back EMF can be 300 Volts plus. That what the 370/440 Volts means. Its the safety voltage that that capacitor will pop at. Theoretical,  the motor can create 440 Volts back EMF before the capacitor fails. 

brewhobbytech, I worked on an Asko dishwasher that used funky clamps. I was told these clamps were used on Asko dishwashers, airplanes and home brew equipment. Is that true or had somebody been sampling their hobby?

[BrewHobbyTech]

21 hours ago, alamo1718 said:

brewhobbytech, I worked on an Asko dishwasher that used funky clamps. I was told these clamps were used on Asko dishwashers, airplanes and home brew equipment. Is that true or had somebody been sampling their hobby?

LOL......I don't know bro, but if I had to guess I'd say they either ingested or smoked something a little more potent than beer. Whatever it was......I might be game to try some. Hey, I haven't had magic mushrooms in many years......it might be time to relive the past and give it another go.........