UniMac Commercial Washer Error Code E d 23: IPM Over Current Shunt
E d 23 on a UniMac QN washer-extractor is a fatal IPM over current shunt error: the drive's power module sensed a surge of current and shut down fast. Drop power so the error resets, but do not test motor wiring yourself. If it returns, call us.
High: a current surge in the drive can damage the motor or power module, so the machine should not be used until checked.
What does UniMac error code E d 23 mean?
The IPM, or intelligent power module, is the part of the drive that switches current to the motor. A shunt is a small precision resistor that lets the drive measure that current. If the shunt reading jumps past the safe level, the drive stops the module within moments, because an unchecked surge could destroy it. E d 23 is the fatal version of that stop, which means the cycle ends and the machine needs attention before it is used again. A shorted motor winding can draw a surge. A drum that is jammed or stuck can do the same, since the motor draws heavy current when it cannot turn. Damaged wiring between motor and drive can short, and the power module itself can fail. A power cycle clears the display, but the cause stays.
Affected models and control systems
This applies to UniMac QN washer-extractors of 20 to 100 lb, such as the UCA020QN, in the CHM1792C family with the front-end control and motor drive.
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 23 on the display
- Washer stopping suddenly as the motor starts
- Humming or a burnt smell from the motor area
- Code returning at the next start
Possible causes
Listed in UniMac's documentation
- A shorted motor winding sending a surge through the drive
- A drum that is jammed or stuck, so the motor cannot turn
- Damaged motor wiring shorting between the phase leads
- A damaged power module inside the drive board
Other likely causes — what usually sits behind error code E d 23 on this control. A technician confirms which one it is before any part is replaced.
- Water that reached the motor terminals and tracked across them
- A small item wedged between drum and shell that locks the basket
- A drive output stage that failed after a past surge
Safe checks before calling for service
- Drop power to the washer so the error resets.
- With power off and the drum still, see whether the empty drum turns freely, without forcing it.
- Do not test the motor wiring yourself.
- Note any burnt smell or noise before the stop.
- If E d 23 returns, call us.
How a technician diagnoses error code E d 23
- Read the code and ask whether a smell, noise or water event came before it.
- With power locked out, check the drum turns freely and nothing is wedged.
- Measure the motor winding resistance phase to phase and to ground.
- Inspect the wiring from drive to motor for chafing or burn marks.
- Check the drive output stage with the motor disconnected.
- Replace the motor, wiring or drive board that fails its test.
- A surge-current stop involves live 208 to 240 V motor circuits that can injure a person.
- Winding and insulation tests need a meter and often an insulation tester.
- Restarting after an over current stop can destroy the power module.
How error code E d 23 differs from similar codes
E d 23 is the fatal current surge, whereas E d 24 is a sustained over current seen over time, and E d 31 is an overload range reading.
Technical reference
- Document
- Washer-Extractor Programming CHM1792C_SVG, Part No. F8641001ENR4, Error Codes Table 29 (pp. 100-107)
- Maker documentation
- UniMac owner support
- 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 UniMac washer error codes
Is E d 23 the motor or the drive?
Either. A shorted motor winding and a damaged drive can both cause it, so we test before replacing parts.
Can I try another cycle?
Power-cycle once to clear it. If it returns, stop, because repeated surges can damage the drive.
Why is it called fatal?
It means the cycle ends and the machine must be checked, rather than the cycle carrying on.
Need help with UniMac error code E d 23?
A technician confirms the cause on site and gives you the price in writing before any work starts.