UniMac Commercial Washer Error Code E dr: Drain Alarm
E dr is the drain alarm on UniMac QN, UC-series and UW pocket hardmount washer-extractors: the water did not drop to the empty level in time. Switch the machine off to clear it, then check that the floor drain is not backed up and the drain hose is not pinched. If E dr returns, call us.
Medium: the cycle stops with water in the tub, and the drain must be cleared before it can run.
What does UniMac error code E dr mean?
After the wash, the control opens the drain valve and waits for the level sensor to say the tub is empty. It allows a programmed drain time, which is 15 minutes on all three controls unless it has been changed. If the water does not reach the empty level within that time, the control stops the cycle and holds E dr until power is cycled. Three things can raise the alarm. A slow or plugged drain keeps the water from leaving. A drain valve that stays shut, or only half opens, does the same. A level sensor that gives a false reading can make the control think water remains when the tub is actually empty. Lint or small items lodged in the drain path are a common reason for the first, and on commercial machines the building drain can back up even when the washer is fine. A cycle left standing in water also soaks the linens, so empty and rewash may be needed.
Affected models and control systems
This applies to UniMac QN (such as the UCA020QN), UC-series and UW pocket hardmount washer-extractors in the CHM1792C, CHM495R and PHM1263R families. On QN machines, reset by disconnecting and reconnecting power.
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 dr on the display
- Water still standing in the drum after the drain step
- Gurgling at the floor drain or water backing up there
- Cycle stopped with a soaked load inside
Possible causes
Listed in UniMac's documentation
- A blocked or backed-up drain line or floor drain
- A drain valve that fails to open fully
- A level sensor or its tube that misreports an empty tub
- Lint or small items lodged in the drain path
Other likely causes — what usually sits behind error code E dr on this control. A technician confirms which one it is before any part is replaced.
- A kinked or flattened drain hose behind the machine
- A shared floor drain overwhelmed when other machines discharge at the same time
- A drain valve whose diaphragm has hardened and no longer opens wide
Safe checks before calling for service
- Switch the machine off at its power control to clear the code. On QN machines, disconnect and reconnect power.
- Look at the floor drain and make sure it is not backed up with water.
- Make sure nothing is pinching or flattening the drain hose.
- Begin a short cycle and see if the drum empties properly.
- If the code returns, note how long the water took to leave and call us.
How a technician diagnoses error code E dr
- Ask how fast the drum empties and whether other machines drain at the same time.
- Check the building drain and the washer's drain hose for blockage.
- Clear lint and debris from the drain path and valve inlet.
- Operate the drain valve and watch it open and close.
- Test the level sensor and its tubing against the real water level.
- Repair or replace the valve or sensor that fails.
- Opening the drain valve housing means water, hot water in some cases, and live valve wiring.
- A wrong level reading can only be told from a slow drain by measuring the actual level against the sensor reading.
- A backed-up building drain may need a plumber, and we help identify which side is the problem.
How error code E dr differs from similar codes
E dr is the drain alarm, whereas E FL is the fill timeout and E Ld is a leak found when the level should hold steady.
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) / PHM1263R family pocket hardmount washer-extractor (UWL/UWN/UWU 035-125) front-end control / CHM1792C family washer-extractor (QN models, 20-100 lb) front-end control
- 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 washer error codes
Is the drain plugged or is the sensor wrong?
Either can raise E dr. We compare the actual water level with the sensor reading to tell them apart.
How long does the control wait?
The drain time is 15 minutes unless it has been changed.
Can I run the cycle again with water in the drum?
Clear the code and check the drain first. Water left in the drum can overflow if the cycle refills.
Need help with UniMac error code E dr?
A technician confirms the cause on site and gives you the price in writing before any work starts.