UniMac Washer-Extractor Error Code Ed10: Low DC Bus

What does UniMac error code Ed10 mean?

The motor drive of a UniMac UC-series washer-extractor keeps an internal DC voltage ready to feed the motor, and it monitors that voltage while the machine runs. When the bus drops below its normal level, the drive posts Ed10 to record the dip. Unlike the high bus message, this one does not end the batch, and the washer continues on its own. A brief sag usually happens at the moment the motor demands a lot of power, such as at the start of a spin, when the supply cannot keep up for a second. If it shows up often, a weak supply or a sag when the motor starts is the likely story, and it is worth watching because the same weakness can eventually stop a batch. The manual lists a supply voltage dip at motor start, other heavy machines sharing the same circuit, a loose or worn wire at the disconnect, and a drive input circuit that sags under load. It applies to Design 2 and 3 models only.

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. Only Design 2 and 3 models report Ed10.

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

• Ed10 flashing briefly and the cycle continuing
• The message appearing at the start of a spin
• Lights flickering at the moment a big machine starts
• An occasional stop if the dip gets deeper

Possible causes

Listed in UniMac's documentation

• A supply voltage dip at the moment the motor starts
• Other heavy machines sharing the same circuit
• A loose or worn wire at the disconnect
• A drive input circuit that sags under load

Other likely causes — what usually sits behind error code Ed10 on this control. A technician confirms which one it is before any part is replaced.

• Undersized feeder wiring to the laundry that drops voltage whenever a large motor accelerates
• A washer and a dryer starting together from one panel and pulling the supply down
• A worn disconnect switch or breaker lug that adds resistance to one phase

Safe checks before calling for service

How a technician diagnoses error code Ed10

1. Read the code and ask how often it appears and during which step.
2. Measure voltage at the disconnect while the washer runs, and while neighboring machines start.
3. Check the disconnect, breaker and terminal lugs for heat marks or looseness.
4. Compare feeder wire size and run length with the machine's rating plate.
5. Test the drive input circuit only after the supply is shown to be sound.

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.