Speed Queen Washer-Extractor Error Code E d 21: Drive Over Voltage
E d 21 on a CHM1792C washer-extractor is an over voltage error on the drive's DC bus. The drive shut the motor off to protect itself, and the load stays wet. Power down as the manual says and have the supply voltage checked.
High: the drive shuts the motor off and the machine will not run until the cause is checked.
- Code
- E d 21
- Maker
- Speed Queen
- Equipment
- Washers
- Applies to
- CHM1792C family washer-extractor (QN models, 20-100 lb) front-end control
What does Speed Queen error code E d 21 mean?
The drive converts the incoming supply into a DC bus, an internal power line that feeds the motor. The drive watches that bus voltage. If it rises above what the drive allows, the electronics could be damaged, so the drive cuts the motor off and the display shows E d 21 (display text: E d 21). The load stays wet in the drum. The owner's manual says to power down and have the input voltage checked, and if it only happens when the spin begins, the motor is the next suspect. A motor can push energy back into the bus when it slows or changes speed. It names three possibilities: supply voltage that runs high at the washer, a motor that feeds energy back during spin start, and a drive board that has failed in its voltage monitoring. Supply voltage that is high at certain times of day, such as when other loads in the building are off, can be the cause. Do not open the door until the lock lets go.
Affected models and control systems
Speed Queen CHM1792C family washer-extractors (QN models, 20-100 lb) with the front-end control. Other washer-extractor families, such as CHM495R, list different codes.
Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.
What you may notice
- E d 21 on the display
- The motor shuts off, often at the start of spin
- The load stays wet in the drum
Possible causes
Listed in Speed Queen's documentation
- Supply voltage running high at the washer
- Motor feeding energy back at spin start
- Drive board voltage monitoring failed
Other likely causes — what usually sits behind error code E d 21 on this control. A technician confirms which one it is before any part is replaced.
- A building supply that rises overnight when other machines are off
- A shared circuit with a loose neutral that lets the voltage swing
Safe checks before calling for service
- Power down the machine, as the owner's manual says.
- Leave the door shut until the lock lets go.
- Keep track of whether the code shows up right as the spin starts.
- Ask us to visit so the supply can be checked safely.
How a technician diagnoses error code E d 21
- Read E d 21 and note when in the cycle it appears.
- Measure the supply voltage at the machine, at rest and during a start.
- Check the neutral and ground connections feeding the washer.
- Inspect the motor and its harness for damage that could feed energy back.
- Replace the drive board only after the supply and motor test normal.
- Measuring supply voltage means working with live 208-240 V.
- A supply problem in the building may involve the laundry's wiring, which has to be corrected by a licensed electrician.
- A drive that monitors its own bus incorrectly is judged only after the supply is proven.
How error code E d 21 differs from similar codes
E d 21 is the high-voltage condition; the drive has other codes for current, temperature and communication.
Technical reference
- Document
- Washer-Extractor Programming CHM1792C_SVG, Part No. F8641001ENR4, Error Codes Table 29 (pp. 100-107)
- Edition
- Part No. F8641001ENR4, January 2020
- Models / control
- CHM1792C family washer-extractor (QN models, 20-100 lb) front-end control
- Section
- Error Codes, Table 29, pp. 100-108 (PDF pages equal printed pages)
- Checked
- October 2026
We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.
Related Speed Queen washer error codes
Is a high supply voltage dangerous for the machine?
It can damage the drive, which is why the drive stops the motor.
Why does the code happen at spin start?
Spin start is when the motor can push energy back, so the motor is a suspect.
Can I keep running the machine?
No. Wait until the supply is checked.
Need help with Speed Queen error code E d 21?
A technician confirms the cause on site and gives you the price in writing before any work starts.