Recalled Dehumidifier - Vacuum pump?

[Curt Harms]

There was a recall on a bunch of different dehumidifiers made by one company. We had one on the list and just got the replacement. Is it possible/would it make sense to repurpose the compressor as a vacuum pump? The machine is rated at 70 pints, the tag says 746 watts, 6.7 amps (I think). they just wanted a pic of the cord cut off as proof that it was longer being used. I wouldn't expect to leave the compressor/vac pump run unattended so I'm not overly concerned about the reason for the recall. I'd expect to use it experimenting with vacuum bagging, I'm not a turner so no vacuum chuck or that sort of thing.

Thoughts please?

[Charles Lent]

Refrigeration/dehumidifiers will create a significant vacuum, but they are designed to circulate a small amount of oil around the closed system to keep all of the internal parts lubricated. It may also overheat without the refrigerant flow, but it will work very well for a while. Don't leave in unattended, not even for just a few minutes.

Charley

[Curt Harms]

Thanks Charles, I did know about the lube but didn't consider the overheating issue. I recall a refrigeration tech talking about sealed compressor motors being undersized. They could get by with it because the motors were running at lower than ambient temperatures.

[Lee Schierer]

I recall a refrigeration tech talking about sealed compressor motors being undersized. They could get by with it because the motors were running at lower than ambient temperatures.

I think your tech was incorrect. Any basketball type refrigeration compressor I have ever worked near was much hotter than ambient temps. Even though it is producing cooling effect in the evaporator, the motor and compressor are still doing work and they get hot. The older piston compressors used in old refrigerators could be used as compressors and probably as vacuum pumps. My grandfather had a compressor system he made from an old refrigerator and a water pressure tank. It ran for many hours for many years.

[Steve Demuth]

Sealed compressors are going to be "hot," because the pump in the enclosure generates heat in compressing the refrigerant. The motor also contributes heat, but much less than the pump itself. Also, undersizing an electric motor makes it run hotter, and less efficiently, leading to shorter life. Given the multi-year warranties on decent compressors, no manufacturer really wants that.