ASKO Dryer Error Code H4

H4 means the dryer's control board has detected that both heating elements are disconnected or non-functional. During a built-in heater check mode, the board measures the temperature rise over two minutes and flags H4 if the increase is 5 degrees Celsius or below. This indicates that neither heater is producing heat. The fault can stem from failed elements, blown thermal fuses, wiring problems, or a power supply issue.

Running the dryer with an H4 fault means the drum will tumble without generating heat, so clothes will not dry properly. The dryer is not immediately dangerous in this state, but continuing to run it without diagnosing the root cause is not advisable. If the fault was triggered by overheating that blew thermal fuses, there may be an underlying airflow restriction such as a clogged vent that also needs to be addressed.

Repair costs depend on the specific failed component. Thermal fuses are inexpensive parts, typically in the range of a few dollars to around $20 each, though labor adds to the total. Heating elements for Asko dryers generally range from $50 to $150 or more per element depending on the model. If professional labor is required, expect the total repair bill to fall somewhere between $150 and $400 or higher depending on parts needed and local labor rates.

A knowledgeable DIYer can perform basic diagnostics such as checking incoming voltage at the terminal block and testing the heating elements and thermal fuses for continuity with a multimeter. To access heater check mode, press the Power button while holding the Dry Beep and More buttons simultaneously. Replacing thermal fuses or heating elements is within reach for experienced DIYers, but working inside an electric dryer involves exposure to high-voltage components, so the power should always be fully disconnected before opening the unit.

A simple power reset will not resolve H4 because the code reflects an actual measured condition, not a control board glitch. The dryer re-enters heater check mode and will re-detect the fault if the heating elements are still open-circuit or disconnected. The underlying cause must be repaired before the error will clear permanently.