Most Common SpeedQueen/Huebsch/UniMac Washer Error Codes, and how to fix them.

Here’s the “hit parade” of error codes you’ll see most on Alliance Laundry Systems commercial washers — Speed Queen / Huebsch / UniMac — especially with Quantum/Quantum Gold/Insight-era controls. The same codes and fixes apply across the three badges because the control platforms are shared. I’ll give you the plain meaning + the field-fast diagnosis/fix.

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1) Fill / water-level faults

E_FL / E:FL / Er, FL — Fill Error

Meaning: Washer didn’t reach the required water level within the maximum fill time. sqinsights.zendesk.com+2Laundry Nation+2
Most common causes

• Hot/cold supply valves not fully open or low building pressure

• Inlet screens plugged with grit/scale

• Failed inlet valve coil or loose spade

• Level/pressure tube issue (air leak, kink, soap gunk in air trap)

Fix / diagnosis

1. Verify supply & pressure at wall. Open valves fully; quick hose-bucket test if needed.

2. Clean inlet screens. Remove hoses, pull/flush screens at the valve body.

3. Valve actuation test. In diagnostics, command hot then cold fill; listen for click + verify flow.

4. Check level system. Inspect pressure hose from tub → sensor for cracks/kinks/water inside; clear air trap.

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Er, OF / E_OF — Overflow

Meaning: Water level rose to overflow threshold. SmartHomeBit+1
Most common causes

• Fill valve stuck open (debris in seat)

• Pressure hose fell off / punctured / air trap blocked

• Level sensor drift/failure

Fix / diagnosis

1. Shut building water off while code is showing.

   • If level keeps rising → inlet valve stuck open → replace/clean valve.

   • If level stops → level sensing problem.

2. Inspect/clean air trap & pressure tube; confirm airtight fit to sensor.

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E_Pr / Er, Pr — Pressure Switch Sequence Error

Meaning: Control sees pressure switch states out of expected order. Laundry Nation+1
Most common causes

• Pressure tube partially blocked with detergent sludge

• Air leak in tube/air bell

• Failed pressure switch

Fix / diagnosis

• Remove/clean pressure hose + air trap.

• Leak-check hose connections.

• If error returns with clean, tight tube → replace pressure switch/sensor.

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2) Drain faults

E_dr / E:dr / Er, dr — Drain Error

Meaning: Max drain time exceeded or water still detected at end of drain/spin. sqinsights.zendesk.com+1
Most common causes

• Coin trap/sump or pump inlet clogged

• Drain hose kinked / standpipe restricted or backing up

• Weak/failing drain pump

• Pressure tube blocked so control “thinks” water remains

Fix / diagnosis

1. Run drain test in diagnostics — should be strong steady outflow.

2. Clean coin trap/sump and check impeller for debris.

3. Inspect hose + standpipe (height, kinks, clogs, slow site drain).

4. If pump has voltage but weak/no flow → replace pump.

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3) Door / interlock faults

E_dL / E_DL / Er, dL — Door Lock Error

Meaning: Door didn’t lock when commanded or lock feedback doesn’t match. How To Fix It+1
Most common causes

• Door sag/striker not entering lock fully

• Failed lock wax motor/solenoid

• Harness break at hinge/front panel area

Fix / diagnosis

1. Mechanical first: Confirm door alignment and striker depth.

2. Lock test: In diagnostics, energize lock and verify “locked” input changes.

3. Meter lock coil/switches and inspect connectors for heat/corrosion.

4. Repair wiring or replace lock.

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door / dor / Er, do — Door Open During Cycle

Meaning: Door-closed input dropped mid-cycle. huebschcommand.zendesk.com+1
Fix

• Reseat/align door, check door-closed switch and wiring.

• If switch is intermittent → replace switch/lock assembly.

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4) Balance / load faults

Er, ub / E_ub — Unbalanced Load

Meaning: Excess vibration; final spin canceled. Authorized Service
Most common causes

• Overloading or one heavy item

• Worn shocks/springs

• Machine not level / weak base

Fix / diagnosis

1. Rebalance load; confirm correct load size practices.

2. Verify machine level & anchoring.

3. Inspect suspension (shocks leaking, springs stretched/broken).

4. Replace worn suspension parts if recurring.

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5) Heating / temperature sensor faults (for heated models)

E_ht / Er, Ht — Heater Error

Meaning: Water temp didn’t rise as expected, or heater circuit fault. Laundry Nation

E_OP — Open Temp Sensor / E_SH — Shorted Temp Sensor

Meaning: NTC/RTD temperature sensor open or short. huebschcommand.zendesk.com+1

Fix / diagnosis (same family)

1. Check heater resistance + insulation-to-ground.

2. Verify heater relay/contactor output during heat step.

3. Test temp sensor resistance vs temp chart; clean/repair connectors.

4. If wiring/sensor good and no heat output → control/relay fault.

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6) Vended / security faults you’ll see in laundromats

Alrn / ALrn — Break-In Alarm

Meaning: Service door or coin vault switch triggered. sqinsights.zendesk.com+1
Fix

• Inspect/adjust vault and service-door switches; check for bent brackets or tampering.

E rr / Err — Coin Error

Meaning: Invalid coin pulse or coin sensor not reading. sqinsights.zendesk.com+1
Fix

• Clear coin drop obstruction, verify coin switch/sensor alignment and harness.

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Quick tech-friendly diagnostic rule

• E_FL / E_OF / E_Pr → water-in / level system (valves, screens, pressure tube, calibration).

• E_dr → drain path (trap, pump, hose, site drain).

• E_dL / door → door lock + wiring + alignment.

• E_ub → load practice or suspension/leveling.

• E_ht / E_OP / E_SH → heater or temp sensing.

• Alrn / Err → vend/security inputs.