I was investigating a condensation buildup in a LG GR-282MF fridge. Removing the cover housing the light and thermostat, I discovered something interesting. A second bulb which was painted with a black coating.
Immediately, I thought this was a spare bulb, but realised that the socket holding the bulb had electrical contacts.
The fridge door lamp was rated at 240V 15W and the black coated lamp was rated at 240V 10W
Doing some research, I found that the black bulb was called a FIR (Far Infra-Red) lamp.
From a LG fridge manual, it quoted:
Far Infrared Rays emitted from Far Infrared Ray Lamp restrains the dryness of the foods and keeps its original form without transforming.
By increasing the nucleic acid, Far Infrared Rays also keeps the aroma and the smell of the food for a long time.
When the refrigerator begins to operate, F.I.R Lamp turns on. During the refrigerator’s operating, the on and
off of the F. I. R Lamp is automatically controlled by the refrigerator inner temperature.
Therefore it is not necessary to handle F.I.R Lamp.
F.I.R Lamp is coated with special materials for the best results of F.I.R Lamp’s effect decreases.
If F.I.R Lamp is veiled or covered, the F.I.R Lamp’s effect decreases.
If you store the foods wrapped in the vinyl or wrapper, not in the vessel with lid, the foods will get more effective F.I.R results.
Some times it pays to read the manual.