One common problem with these combo laundry units is that they'll stop drying the clothes. The dryer portion of the combo unit is a condenser type dryer. It works on the principal that water condenses on a cool surface, similar to moisture collecting on a cold drink on a hot and humid summer day. A fan circulates air through the warming duct, drum, and condenser and over and over. The air is warmed because warmer air holds more moisture than cooler air and the heat causes more of the water to be evaporated form the laundry. The warm, moist air is directed through the condensing duct, which is cooled by a spray of cold water. This difference in temperature causes the moisture to precipitate in the condenser, where it and the cooling water are exhausted by the drain pump. The air, now dry, is passed over the warming element and through the laundry again as the process repeats itself. Because the air is recycled instead of exhausted, a vent and lint filter are not necessary for this type dryer.
If you don't work on a lot of these units, they can be strange and mysterious beasts, even leading some techs to go insane on blind, parts-changing rampages in a vain attempt to fix a no-drying complaint.
Brethren, let us unbunch our panties and unfurl our brows while Brother john63, Dean of LG Laundry Appliantology, reveals to us the solution which, like most technical solutions, is stunningly simple once you hear it, yet ever elusive to the uninitiated:
Plan of attack as follows...
1) Remove the DUCT from the tub. Pay particular attention to the area of the duct---where it connects
to the bottom of the tub. Clean the duct system thoroughly.
2) Replace the DRAIN MOTOR (4681EA2001T)
3) Verify that the COLD WATER VALVE ASSY is the ***correct*** one. If not---replace it (5220FR2008E)
Repeat the above steps---every 3 years.
Laundry can be loaded into the tub---3/4s full.
When the laundry becomes wet during the *wash* cycle---the laundry will *sag* within the tub---to approximately 1/2 or less of the tub opening.
This will permit faster drying---than an overloaded combo unit.
Source: LG Combo Washer/dryer not drying