UniMac Commercial Washer Error Code E d 44: Shunt Detection Hardware
E d 44 on a UniMac QN washer-extractor is a hardware failure in the drive's overcurrent shunt detection circuit. Take the washer off power to reset the display, try once, and call us if E d 44 returns. The maker points to the drive board.
High: the drive's current protection has failed its own check, so the machine should not run until it is repaired.
What does UniMac error code E d 44 mean?
The drive protects itself with a shunt, a small precision resistor that lets it measure motor current and catch dangerous spikes. The circuit that reads the shunt has its own self-check. E d 44 means that check failed, so the safeguard itself cannot be trusted. With no reliable current protection, the drive will not run the motor, and the cycle stops. This is a different situation from E d 23 and E d 24, where the protection worked and found too much current. Here the protection failed, which is why the maker points to the drive board. A failed shunt detection circuit on the board is the main cause. A loose connector between the drive board and the rest of the machine, or poor incoming power disturbing the drive's current checks, can also trip it. Cycling power may let the display clear without removing the cause.
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 44 on the display
- Cycle stopping at the first attempt to spin
- Code returning after a restart
Possible causes
Listed in UniMac's documentation
- A failed shunt detection circuit on the drive board
- A loose connector between the drive board and the rest of the machine
- Poor incoming power disturbing the drive's current checks
Other likely causes — what usually sits behind error code E d 44 on this control. A technician confirms which one it is before any part is replaced.
- Heat damage to the board around the shunt from years of heavy extract loads
- A supply that sags at start-up when other equipment starts on the same circuit
- A ribbon or plug on the drive board that has worked partly out of its socket
Safe checks before calling for service
- Reset the display by taking the washer off power.
- Wait a moment, power up and try once.
- Do not open the cabinet.
- If E d 44 returns, call us, since the maker points to the drive board.
- Tell us whether the code appears at every start.
How a technician diagnoses error code E d 44
- Confirm the code returns after a power cycle and ask if it started after a power event.
- Measure incoming voltage at the disconnect under load.
- With power locked out and the drive discharged, inspect the board connectors for seating and corrosion.
- Look for heat damage around the current sensing parts.
- Compare the board part number with the machine data.
- Replace the drive board only after the supply and connectors are cleared.
- The drive board holds stored charge and sits next to live 208 to 240 V power terminals.
- Judging a self-check failure inside the board needs the right procedure and part number.
- Running a drive with a failed current safeguard can destroy the board and motor.
How error code E d 44 differs from similar codes
E d 44 is a self-check failure of the protection circuit, whereas E d 23 and E d 24 are real current events.
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 the motor drawing too much current?
Not necessarily. E d 44 says the circuit that measures current failed its own check.
Can I keep restarting until it runs?
No. If the safeguard cannot be trusted, running risks damage.
Will new wiring help?
Seldom. The maker points to the drive board, so we check it and its connections.
Need help with UniMac error code E d 44?
A technician confirms the cause on site and gives you the price in writing before any work starts.