UniMac Commercial Washer Error Code E d 64: IPM Sensor Open
E d 64 on a UniMac QN washer-extractor is a fatal IPM temperature open error from the drive hardware. The sensor that reads the power module temperature reads open, so the drive cannot tell how hot it is. Take power off, leave the cabinet shut and call us if it appears again.
High: the drive will not run without a module temperature reading, so the washer is out of service.
What does UniMac error code E d 64 mean?
The drive's power module carries a temperature sensor that tells the drive how hot the module is. E d 64 appears when the circuit to that sensor reads open, as though a wire were cut. Without a temperature reading, the drive cannot judge whether the module is safe, so it stops the cycle. It is the open-circuit partner of E d 63 and points to the drive board. An open sensor circuit on the board is the main suspect. A connector at the sensor input that has come loose can create the same reading, and so can corrosion or damage on the board near the sensor. Taking power off resets the message. If the cause is a broken trace or a corroded pad, it will come back the next time the board warms up and the contact opens.
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 drive board.
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 64 on the display
- Cycle stopping soon after warm-up
- Code that comes and goes as the cabinet warms
Possible causes
Listed in UniMac's documentation
- An open module temperature sensor circuit on the drive board
- A connector at the drive board sensor input that has come loose
- Corrosion or damage on the drive board near the sensor
Other likely causes — what usually sits behind error code E d 64 on this control. A technician confirms which one it is before any part is replaced.
- A solder joint at the sensor that cracks with repeated heating and cooling
- A harness tug during a past service that loosened the sensor lead
- Detergent vapor reaching the board and corroding the sensor pads
Safe checks before calling for service
- Take power off the washer, which resets the message.
- Do not open the cabinet.
- Make sure the machine area is clean and dry.
- Please call us if E d 64 appears a second time.
- Jot the time of the first appearance on a note.
How a technician diagnoses error code E d 64
- Confirm the code returns and note whether it appears after warm-up.
- With power locked out and the drive discharged, inspect the sensor connector and board for corrosion or cracks.
- Reseat the connector and check the pins.
- Measure the sensor circuit for continuity and compare it with the expected value.
- Look at the solder joints near the sensor.
- Replace the drive board when the sensor circuit is proven open.
- Opening the drive area exposes stored charge and live 208 to 240 V terminals.
- An intermittent open needs the machine warmed up and tested while it runs.
- Replacing a board without finding corrosion or vapor sources invites a repeat.
How error code E d 64 differs from similar codes
E d 64 is the open sensor reading, E d 63 is the shorted one, and neither is a real over temperature.
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 the difference between E d 63 and E d 64?
E d 63 reads the sensor as shorted. E d 64 reads it as open. Both stop the drive.
Why does it return after warm-up?
A cracked joint or corroded pad can lose contact as the board heats up.
Can I run the washer without the sensor?
No. The drive will not run without a temperature reading.
Need help with UniMac error code E d 64?
A technician confirms the cause on site and gives you the price in writing before any work starts.