Samsung Air Conditioner Error Code E429

E429 indicates a main cooling solenoid valve open circuit error. The control board is detecting that the electrical circuit to the main cooling solenoid valve is broken or has lost continuity. This prevents the system from controlling refrigerant flow properly, so cooling operation is disabled until the fault is corrected.

The unit will typically not operate normally when E429 is active, as the system disables cooling to protect itself. Attempting to force operation with a known solenoid valve fault is not advisable, since improper refrigerant flow control can stress the compressor and other components. It is best to leave the unit off until the fault is diagnosed and repaired.

A power reset may temporarily clear the fault display, but if the underlying open circuit condition in the solenoid valve wiring or coil still exists, the error will return once the system attempts to actuate the valve again. A reset is useful for confirming whether the fault is intermittent, but it does not address the root electrical problem and should not be relied on as a fix.

Some basic checks, such as inspecting visible wiring and reseating connectors, can be done by a knowledgeable homeowner. However, testing solenoid valve coil resistance and diagnosing control board faults requires a multimeter and familiarity with electrical components inside the unit. Since this fault also involves the refrigerant system infrastructure, a certified technician is recommended for any repair involving the solenoid valve replacement itself.

Repair costs will vary depending on the root cause. If only a wiring connector needs reseating or a harness section is replaced, costs may range from roughly 75 to 200 dollars including labor. Solenoid valve coil or full valve replacement typically falls in the 150 to 400 dollar range depending on the model and labor rates. Control board replacement is the most expensive scenario, often ranging from 300 to 600 dollars or more.