UniMac Washer-Extractor Error Code Ed03: Tachometer Error
Ed03 is a tachometer error: the drive found its tach input damaged at power-up, or saw no tach signal once the motor started. Power down, leave the panels on, try once, and call us if Ed03 returns.
High: the drive cannot regulate motor speed without the tach signal, so the washer stops until it is repaired.
- Code
- Ed03
- Maker
- UniMac
- Equipment
- Industrial laundry
- Applies to
- CHM495R family washer-extractor front-end control (20-100 lb)
What does UniMac error code Ed03 mean?
A tachometer tells the drive how fast the motor is actually turning. The drive on a UniMac UC-series washer-extractor needs that speed feedback to regulate the spin, so it checks the tach input twice. At power-up it looks for a damaged tach input, and after it begins sending output to the motor it expects to see pulses come back. If the input is damaged, or no signal arrives, the drive cannot control speed and stops the batch with Ed03. Without feedback, the drive could run the motor too fast or not fast enough, which strains the drum and bearings. The manual lists four causes: a tach wire or motor connector that is loose or damaged, a damaged tach input at the H3 terminal on the drive, a motor tach sensor that has failed, and a drive board that cannot read the tach. The message applies to Design 2 and 3 models only. Checking the H3 terminal and the tach connections is a job for a technician, so the operator's part is to power down, keep the panels closed and make one attempt to restart.
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 machines report Ed03.
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
- Ed03 on the display and the batch stopped
- Drum that does not start turning after the door locks
- Error appearing within seconds of a start or at spin
- Motor humming without the drum reaching speed
Possible causes
Listed in UniMac's documentation
- A tach wire or motor connector that is loose or damaged
- A damaged tach input at the H3 terminal on the drive
- A motor tach sensor that has failed
- A drive board that cannot read the tach
Other likely causes — what usually sits behind error code Ed03 on this control. A technician confirms which one it is before any part is replaced.
- A tach cable that chafed against the frame where vibration is strongest
- Moisture or detergent that reached the motor connector and corroded the tach pins
- A tach sensor on the motor shaft that has loosened or gathered lint and grease
Safe checks before calling for service
- Power the machine down at its control.
- Confirm from outside that nothing is leaning on the machine or its cables.
- Leave the panels on; the H3 terminal and tach wiring are for a technician.
- Power up and try once. If Ed03 returns, note whether it happens at start or during spin.
How a technician diagnoses error code Ed03
- Read the code and note whether the message appears at power-up or after the motor begins to run.
- Inspect the tach connector at the motor and the wire run for damage, wear or moisture.
- With power locked out, check the tach wiring continuity between the motor and the H3 terminal on the drive.
- Test the motor tach sensor output against the maker's specification while turning the shaft.
- Replace the tach sensor, harness or drive only after the failing link is proven.
- Checking the H3 terminal means opening the drive area, where live line voltage and stored charge are present.
- The tach circuit carries a small signal that is easily damaged by pulling or reseating connectors incorrectly.
- Deciding between a bad sensor and a bad drive input needs a meter and the maker's specification.
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.
Related UniMac industrial laundry error codes
What does the tach actually do?
It reports motor speed to the drive. Without that feedback the drive cannot regulate the spin and stops the batch.
Will a power cycle clear it?
It can clear a one-time reading problem, but a damaged wire or sensor will bring it right back.
Is Ed03 the same as Ed04?
No. Ed04 is a rotor that would not turn. Ed03 is about the missing speed signal.
Need help with UniMac error code Ed03?
A technician confirms the cause on site and gives you the price in writing before any work starts.