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Dehumidifier Saved by Oil & a Syringe
February 1, 2012
3 Min Read
When the water catch bin of my dehumidifier was full, the unit would shut off. I would empty the bin and place it back on the dehumidifier. You could also attach a garden hose and let the unit empty into the sump pit. Yet, the question was: How would that affect the life of my sump pump bearings?
When the bin was reinstalled, the dehumidifier would start. The compressor and fan each have their own distinctive sounds. One day I heard the compressor but not the fan. I removed a few screws, which gave me access to the fan motor. Sure enough, it had seized up.
I was able to turn the armature shaft by hand. I got a little syringe and put a few drops of oil where the shaft meets the bearing. According to the manual, "The fan motor has been permanently lubricated at the factory." I guess that's permanently or four years, whichever comes first.
I was lucky it ran for four years. The warranty was for one year. I worked the fan blade back and forth a few times to free up the shaft, and then applied power -- it ran. Luckily, the bearings have a felt pad in contact with them to act as a reservoir, so I let the pads have a few extra drops of oil. I have to repeat this process every few years, but it's no big deal.
After that problem was solved, the clothes dryer stopped working. When the start button was pressed, the drum did not rotate. The manual says that the motor has sealed-in lubricant. In the troubleshooting section, under the heading of "Motor has power but will not start or run," it said, "For bad bearings, replace motor."
I figured I would mess with the motor since it was already junk. The motor drives the belt that spins the drum, and also has the impeller for the blower on the other end. We have one of those primitive dryers with no electronics, no Internet hookup, and you can't get an iPhone app that will turn it on when you are at the ball game.
Once you get the access panel off the back, you remove two screws and release the tension on the belt. Then you can pull it free from the blower housing. After that, it's a simple matter of deciding where the oil should go. I got the syringe again, and I used plain old automotive engine oil. Usually the motor is not frozen solid enough that you can't turn it. It's just that the motor can't start rotating because of the extra friction of the dry bearings. A little hand coaxing will get the oil to creep into the gap between the shaft and the bearing ID.
This entry was submitted by Pete Ostapchuk and edited by Rob Spiegel.
Pete Ostapchuk was a radar operator on a Nike Hercules site in the Army where he studied electronics through correspondence courses. He ended up in the electronics engineering department at CTS for eight years, where he worked on industrial automation projects. He worked at Bayer for eight years in medical diagnostics R&D.
Tell us your experience in solving a knotty engineering problem. Send stories to Rob Spiegel for Sherlock Ohms.
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