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Discussion Starter #1
Hi;
I have a 40+ year old Sears Coldspot Dehumidifier. It still runs and removes water from the air, but the humidistat control failed about 10yrs ago so I replaced it with an in-line wall mounted control that I simply installed between the 115V outlet and the unit's plug.


I have noticed that this appliance runs very warm. The outside (metal) cabinet is very warm when it has been running for a while, and the compressor is too hot to touch.


I checked the current draw. It starts at about 7.6A and gradually drops to 7 Amps, but may drop further as it runs. I only measured for current for a few minutes when it started up.
The rated current is 6.5A.


Because this unit is so old, I am thinking perhaps it's not very safe to continue using it. Of course, being on a metal chassis with metal cabinet, the fire hazard should be fairly low - so long as the space around the appliance is kept clear.


I had purchased a second dehumidifier about 6 years ago - a Haier brand - but it lasted only 2 years before it lost its charge. It was already past warranty, and repair would have cost half the price of the unit, so I got rid of it. I have never shopped for a new one since.


This unit is used in the basement, which is finished but with a concrete floor. The only reason I feel the need for a dehumidifier is that I keep boxed foods stored in the room, and don't want anything to spoil. That said, most of the foods are sealed in plastic anyway.
Still, the basement does get a damp smell when the dehumidifier isn't running.


I seem to recall having cleaned the coils once, taking it outside and spraying with the hose - but that was a very long time ago, and no one has done any service on it since.


What do you think?


Thanks
FW
 

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Well, a plugged condenser will cause high compressor amp draw and increase the outlet air temperature.

Take it apart and see if the coil is plugged.

The filters supplied with these units are usually poor quality and let a lot of dirt through. The evaporators on a lot of old units are made up of aluminum tubes with no fins so they don't clog with dirt on the air side.
 
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Discussion Starter #3
Thanks for the advice.
Funny thing: Just after I posted here, I went back to the basement and removed the cover from the unit. The condenser coils were covered with dust, but not as bad as I thought they might have been. I cleaned them, and the evaporator coils are, as you suggested, finless, but I was able to clean the slime off of them as well. I also cleaned the fan blades and body, and checked that the fan is running.


There have never been any filters on this unit.


I have the humidistat (wall mounted just behind and above the unit) set to 50%. Perhaps though, the location of the humidistat isn't the best, as it is above the unit where its own hot exaust will rise, and perhaps skew the humidity at the control.

I placed a humidity meter in the room near, but not in the hot air flow of the dehumidifier, and will check it in the morning.


In reality, this humidifier is probably far too small for the basement, but it resides in a walled off room with the door kept open and a large fan moving air in the other (larger) section of the basement. So far in all the years we have had this setup, and with food stored there, nothing has gone bad or become mouldy.


So far as compressor temperature goes, I am not aware that it is tripping the high-temp switch, but I'm not down there all that much, so I may not know if that is happening. I would expect to hear the fan running without the compressor if that were the case, and I have never observed that condition.
 

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Did you just brush off the condenser? It may need to be rinsed out with the fan removed to remove the embedded dirt.

Check the amp draw with a clean coil, see if it's within normal limits. Don't worry about the compressor being hot as long as the low side refrigerant line connected is cool and the amp draw is normal.
 

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Discussion Starter #5
Yes, I only brushed off the condenser. It was rather late, so I didn't have the time to do the full wash. I'll try to get to that over the next few days. Is there anything besides the fan that should be removed before hosing it down? The old humidistat doesn't work anyway, so no need to remove it.
 

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An unattended appliance in the basement should be plugged into a GFIC.


If that is the case I would have no problem using a 40 year old unit. It is probably made better than anything you could buy. Because of the sage it probably use more current than a modern one.
 

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honestly that old unit is probably safer than a new one made with plastic casing, controlled by a cheaply made circuit board.

do check all your electrical connections and the cord.

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Anything electrical except the compressor can't get wet.
 

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the condenser coils in those old units have the fins spaced further apart compared to new ones so it was less important to have a filter back then.

Today's units have to comply with much stricter energy efficiency regulations and there's a push to build them as cheap as possible.

so the tubes are very thin and the fins spaces closed together. energy efficient until they get plugged or spring a leak just after the warranty period.

it's possible to make durable energy efficient units but the profit margin would be much lower than today.
 
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