Dan O. -- Friday, 1 December 2000, at 3:36 p.m.
: The dehumidifier is building up frost on the
: coils and seems to be running continuously.
: It is located in an unfinished basement in a
: five year old home.
If the evaporator coil is frosting over completely, the most common cause is that the room temperature is too cold. Dehumidifiers are not meant to be used when the room temperature drops much below 70°F and certainly not below 65°F.
Another possible cause is poor air flow through the unit. If the fan motor is not turning fast enough (or at all) or the evaporator, condenser or filter (if used) are plugged, can also cause this symptom.
If the temperature is borderline, you can try elevating the unit off the floor into the warmer air higher up in the room (remember, hot air rises). I've also heard that an external fan blowing additional air into the unit can help in some circumstances.
: Should the dehumidifier be shut down during the
: winter months?
A dehumidifier should not be operated when the coils are totally frosted over. This condition can lead to damage to the compressor. Some models are available with a 'de-ice' control. These will shut the compressor down in such circumstances. If you need dehumidification but units have a tendency to frost over, this design offers some protection for the compressor (which is expensive $$$+ to replace if damaged).
You can also purchase specially designed "basement dehumidifiers" (see the link below) which will continue to operate even in slightly colder temperatures like basements often get.
: Or is there a possible problem with it?
A problem in a dehumidifier can usually be identified by a *partially* frosted evaporator coil which would usually indicate being short of refrigerant or failing compressor. If the evaporator is not getting cold at all when the compressor is running, that is a sign of being totally out or refrigerant or of a faulty compressor.
Dan O.
Appliance411
The Appliance Information Site
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