UniMac Commercial Washer Error Code E d 32: Back EMF Error
E d 32 on a UniMac QN washer-extractor is a back EMF error: the voltage the spinning motor generates was read as off. Cut the main power to reset it, check that the empty drum turns freely, and call us if E d 32 reappears.
Medium: the cycle stops until power is cycled, but the cause is a measurement problem that can often be traced.
What does UniMac error code E d 32 mean?
A motor that is turning also acts like a small generator. The voltage it generates, known as back EMF, tells the drive how fast the motor is really turning and in which direction. The drive reads that voltage to confirm that what it commanded is what the motor is doing. E d 32 appears when the reading does not make sense. That points to the motor harness, the motor itself or the drive board. A drum or motor that does not turn freely can distort the signal, a damaged harness can carry a bad reading, and a motor with a weak winding can produce an off value. The cycle stops and the machine needs the power cycled to clear the code. It is a measurement problem as much as a power problem, so a wiring check usually comes before any part is replaced.
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 32 on the display
- Cycle stopping as the drum speeds up
- Drum seeming to hesitate or surge before the stop
Possible causes
Listed in UniMac's documentation
- A drum or motor that does not turn freely, distorting the signal
- A damaged motor harness giving a bad back EMF reading
- A motor with a weak winding producing an off reading
Other likely causes — what usually sits behind error code E d 32 on this control. A technician confirms which one it is before any part is replaced.
- A harness shield that is damaged so electrical noise corrupts the sensed voltage
- A connector with a high-resistance contact that drops the reading under vibration
- A drive input that has aged and no longer measures the signal accurately
Safe checks before calling for service
- Start by cutting the main power, which resets the message.
- With power off and the drum still, check that the empty drum turns freely by hand.
- Do not open panels to touch the harness.
- Run one cycle and watch where in the spin the code appears.
- Should E d 32 reappear, please call us.
How a technician diagnoses error code E d 32
- Read the code and ask at what point in the spin it appears.
- With power locked out, turn the drum by hand to rule out drag.
- Inspect the motor harness and connectors for damage and corrosion.
- Check winding resistance of the motor and compare the phases.
- Check the drive's sensing input once the harness and motor pass.
- Replace the harness, motor or drive that fails its test.
- The harness carries live motor voltage and sensing leads that are easily damaged.
- A back EMF reading needs a meter, and sometimes a scope, to judge.
- Replacing a drive for a harness problem wastes money and leaves the code in place.
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
What is back EMF in plain terms?
It is the voltage a spinning motor generates, which the drive uses to confirm the motor's speed.
Is the drive board the likely cause?
Not first. The harness and motor are checked before the board.
Will cutting power fix it?
It clears the message. A damaged harness or weak winding brings it back.
Need help with UniMac error code E d 32?
A technician confirms the cause on site and gives you the price in writing before any work starts.