Online Training Manual for LG Products - Heater and Driver      

The heater driver circuits are similar for both heaters on the machine: the wash heater, which heats the water in the tub to the specified temperature; and the steam generator heater, which boils water to make steam for the steam cycles. The elements are similar, but not interchangeable, approximately 1,000-watt electric heaters.

The heaters may vary depending upon the series of the machine and the kind of steam system it uses. Steam machines use the separate module of a steam generator. TRU-Steam™ machines use the wash water heater in the base of the tub to heat the water to produce steam.

When the heater is energized, use your multimeter to read the voltage. It should be approximately 120 VAC. You can read the voltage either at the heater terminals or at its connector on the main board. With the heater element disconnected from the circuit, the resistance should be 15 ohms ± 20%. You can determine if the heater is getting power in the TEST MODE by commecting your meter to the heater leads before running the test. The heater is powered for approximately 3 seconds, so you have to plan ahead and look quickly. Another valid method is to connect your machine through a Kill-A-Watt meter to see is the heater pulls current when activated. If the board supplies power but the heater element is defective, you will not see the current draw during the test.

When using the connectors for test points, pay particular attention to connector and wire colors and numbers.

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