UniMac QN Washer-Extractor Error Code E LP: Low Level Pressure Switch
E LP is the low level pressure switch error on a UniMac QN washer-extractor with heat. It is enabled only during the Factory Test Cycle. Turn the washer off and on, then run a normal cycle; call us if E LP shows on a normal cycle.
Low: tied to the Factory Test Cycle, so normal washing is not affected.
- Code
- E LP
- Maker
- UniMac
- Equipment
- Industrial laundry
- Applies to
- CHM1792C family washer-extractor (QN models, 20-100 lb) front-end control
What does UniMac error code E LP mean?
E LP is the low level pressure switch error on a QN machine with heat, such as the UCA020QN. It is enabled only during the Factory Test Cycle, which is a service routine and not a production wash. At a certain step of that test, the control checks the pressure switch that senses a low water level. It found the switch in the wrong state, so it stopped the test and displayed the code.
Most laundries never see it, since it belongs to the test cycle and not to normal production washing. If it appears, the first question is whether the test cycle was started by mistake. Beyond that, the pressure switch position, the tubing to the switch and the wiring at the switch are the things a technician looks at.
Turn the washer off, then on again. Start a normal cycle and watch the first fill, and avoid starting the test cycle again. Check that the supply valves are open. If E LP shows on a normal cycle, call us.
Affected models and control systems
E LP is listed for the CHM1792C family washer-extractors, the QN models from 20 to 100 lb, with the front-end control; the manual's example model is the UCA020QN. It applies to QN machines with heat.
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
- The display shows E LP during a test cycle
- The code appears after someone selected an unusual program
- Normal cycles run without the code
- The fill step looks normal when the code is up
Possible causes
Listed in UniMac's documentation
- Pressure switch position
- Tubing to the switch
- Wiring at the switch
- Whether the test cycle was started by mistake
Other likely causes — what usually sits behind error code E LP on this control. A technician confirms which one it is before any part is replaced.
- Test cycle selected by a curious operator or after a control reset
- Switch tube pinched during cabinet work
- Switch wire pulled loose at the terminal
- Switch contacts stuck from age
Safe checks before calling for service
- Turn the washer off, then on again.
- Start a normal cycle and watch the first fill.
- Avoid starting the test cycle again.
- If E LP shows on a normal cycle, check that the supply valves are open and call us.
How a technician diagnoses error code E LP
- Read the code and ask which program was running.
- Confirm whether the Factory Test Cycle was selected.
- Check the pressure switch tube for kinks and water.
- Test the switch contacts with air pressure and a meter.
- Check the switch wiring and replace the switch only if it fails.
- Testing the pressure switch means opening panels near live wiring.
- Applying air to the switch tube needs the right method to avoid damage.
- A switch in the wrong state and a pinched tube look identical from outside.
How error code E LP differs from similar codes
E LP belongs to the QN test cycle, while E Pr is the similar test-cycle pressure switch code of UC machines in Design 1.
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 industrial laundry error codes
Is E LP a real failure?
Usually not. It comes from the test cycle, which production washing does not use.
Why did the test cycle start?
Someone may have selected it by mistake. Keep it away from daily use.
What if it appears in a normal wash?
Then the switch or its tube may be at issue, and we should check it.
Need help with UniMac error code E LP?
A technician confirms the cause on site and gives you the price in writing before any work starts.