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Error code reference

Bosch Dryer Error Code E:29

Compressor inverter

Bosch codesBosch dryer codes

Compressor inverter - blocked rotor.

First step from the service manual

Check compressor windings and its electrical connections.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What E:29 means on a Bosch dryer

The E:29 error code on a Bosch dryer indicates a blocked rotor condition within the compressor inverter system. This fault is specific to heat pump dryers, which use a refrigerant-based compressor to generate drying heat rather than a traditional electric heating element. The inverter board controls the variable-speed operation of the compressor motor, and when it detects that the rotor has stopped turning or is unable to rotate freely, it triggers this code to prevent motor burnout and further electrical damage.

A blocked rotor condition means the compressor motor shaft is either physically seized or the inverter is receiving feedback indicating stalled rotation. The inverter monitors current draw and motor feedback signals continuously. If the rotor is mechanically locked, the motor will pull excessive current without producing rotation, which the inverter detects as a fault condition. This can stem from compressor mechanical failure, refrigerant pressure imbalance causing hydraulic lock, or electrical faults in the compressor windings themselves.

The first diagnostic step is to check the compressor windings and all associated electrical connections. A technician should measure winding resistance across each terminal pair to identify open circuits, shorts to ground, or imbalanced resistance readings that indicate internal motor damage. Loose or corroded connections between the inverter board and compressor can also produce false blocked rotor signals by disrupting the control and feedback circuits.

Source: manufacturer service documentation.

Common causes of E:29

  1. 01

    Failed or seized compressor

    Part replacement

    Internal mechanical failure of the compressor can cause the rotor to lock up completely. This is identified by checking winding resistance and listening for any abnormal sounds or complete silence when the compressor attempts to start.

  2. 02

    Faulty compressor windings

    Part replacement

    Damaged or shorted windings inside the compressor motor prevent proper rotation. Testing resistance across each winding terminal pair will reveal open circuits, shorts to ground, or significantly unbalanced readings.

  3. 03

    Loose or corroded electrical connections

    Wiring / connection

    Poor connections between the inverter board and the compressor can disrupt control signals and cause a false blocked rotor fault. Inspect all connector pins and wiring harness terminals for corrosion, looseness, or heat damage.

  4. 04

    Defective compressor inverter board

    Part replacement

    The inverter board itself may be malfunctioning, sending incorrect drive signals or misreading motor feedback. If winding resistance and connections check out correctly, the inverter board becomes the primary suspect.

  5. 05

    Refrigerant pressure issue causing hydraulic lock

    Wiring / connection

    An abnormal refrigerant pressure condition can cause liquid refrigerant to enter the compressor cylinder, physically preventing rotation. This typically requires pressure testing of the refrigerant circuit by a qualified technician.

See the test procedure for each cause

Frequently asked questions about E:29

What does E:29 mean on a Bosch dryer?
E:29 on a Bosch dryer indicates a blocked rotor fault in the compressor inverter system. This means the heat pump compressor motor is not rotating as expected, either due to a mechanical seizure, winding failure, or an electrical problem in the inverter circuit. The dryer shuts down automatically to prevent further damage when this condition is detected.
Can I fix E:29 on my Bosch dryer myself?
Basic steps like inspecting and reseating electrical connections to the compressor are within reach for experienced DIYers. However, testing compressor windings requires a multimeter and some technical knowledge, and any work involving the refrigerant circuit must be performed by a certified technician. Compressor or inverter board replacement is also a job best handled by a qualified repair professional.
Is it safe to keep using my Bosch dryer when E:29 is displayed?
No, you should not continue operating the dryer while E:29 is active. The error indicates the compressor is not functioning correctly, and running the appliance in this state risks overheating the motor, damaging the inverter board, or causing additional electrical harm. Disconnect the dryer from power until the fault is properly diagnosed and repaired.
How much does it cost to repair a Bosch dryer with error code E:29?
Repair costs vary depending on the root cause. If the issue is simply a loose or corroded electrical connection, the cost may only involve a service call fee, typically in the range of $75 to $150. Inverter board replacement can run $200 to $400 including parts and labor. A full compressor replacement is the most expensive outcome, often ranging from $350 to $700 or more depending on parts availability and labor rates in your area.
Will resetting my Bosch dryer clear the E:29 error code?
Performing a reset by unplugging the dryer for a few minutes may temporarily clear the code, but if the underlying fault with the compressor or inverter is still present, the error will return quickly once the dryer attempts to operate. A reset alone does not fix a seized compressor, damaged windings, or a failing inverter board. Proper diagnosis and repair of the root cause are required to permanently resolve E:29.

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