UniMac Washer-Extractor Error Code Ed05: IGBT Overcurrent

What does UniMac error code Ed05 mean?

The motor drive in a UniMac UC-series washer-extractor builds the motor's power with IGBTs, which are fast electronic switches in its power stage. The drive measures the current through that stage, and if it finds an overcurrent shunt condition, it shuts off immediately because the switches can be destroyed in a fraction of a second. The batch stops and Ed05 shows. A shorted motor or damaged motor wiring is one way current can climb. A drum that drags and forces the motor to draw extra current is another, and a poor input line is a third. The manual asks for two minutes powered down at least, plus a check that the motor is not shorted. The message applies to Design 2 and 3 models only. The reason it asks for time off is that the drive needs to discharge and cool before it is powered up again. If Ed05 returns after that wait, the washer should stay off, because repeated power-ups into a short can damage the drive.

Affected models and control systems

This applies to the CHM495R family of UniMac UC-series washer-extractors, 20 to 100 lb, with the motor drive, for example the UCH020GNF. It is reported on Design 2 and 3 models only.

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

• Ed05 on the display and the batch stopped
• A motor that stopped suddenly during spin acceleration
• A faint burnt smell near the drive
• The code returning right after a power-up

Possible causes

Listed in UniMac's documentation

• Motor and leads for a short
• Drive power stage
• Drum drag that raises current
• Input line condition

Other likely causes — what usually sits behind error code Ed05 on this control. A technician confirms which one it is before any part is replaced.

• Motor insulation that has broken down from moisture and now leaks current to the frame
• Damaged motor leads rubbing on the frame or pulley in the base
• A drive output stage that has weakened after earlier surges

Safe checks before calling for service

How a technician diagnoses error code Ed05

1. Read the code and any other Ed codes stored with it.
2. Lock out the power, wait for the drive to discharge, and inspect the motor leads for damage.
3. Meter the motor windings phase to phase and to ground for a short, and compare with the specification.
4. Turn the drum by hand to rule out heavy drag, and check the incoming line condition.
5. Replace the motor or drive only after the shorted element is found.

Technical reference

Document

Washer-Extractor Programming CHM495R_SVG, Part No. F8208501ENR10, March 2017, Error Codes (pp. 36-37)

Maker documentation

UniMac owner support

Edition

Part No. F8208501ENR10, March 2017

Models / control

CHM495R family washer-extractor front-end control (20-100 lb)

Section

Error Codes table, pp. 36-37 (E Pr only on Design 1 models; Ed01-Ed11 on Design 2 and 3 models)

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.