🧯 Commercial Dishwasher Troubleshooting Guide

🧯 Commercial Dishwasher Troubleshooting Guide

If your commercial dishwasher isn’t working as it should, don’t panic. Most common issues can be diagnosed and resolved quickly with the right approach. Whether you’re using a door-type, rack conveyor, or undercounter model, the guide below outlines the most frequent problems and recommended solutions to get your unit back in service fast.

⚠️ Important: Always follow your equipment manufacturer’s guidelines and contact an authorized service technician when electrical or mechanical repairs are needed.

🚪 Door-Type Dishwasher Troubleshooting

Applicable for models such as MD-1000HT, MD-1000LT, D-HB High Temp, D-H1 High Temp, and D-LF Low Temp.

🧼 Machine or Cycle Won’t Start

• Door not closed properly: Make sure both doors are fully shut and sealed.

• Broken door safety switch: Contact an authorized technician for replacement.

• Faulty start switch: Requires repair or replacement by a professional.

• Main switch is off: Verify that the main disconnect switch is turned on.

• Overload tripped: Have a technician reset the overload in the control box.

🌡️ Low Final Rinse Temperature

• Low incoming water pressure: Clean or replace the inlet valve.

• Faulty thermometer: Replace if temperatures remain inaccurate after calibration.

💧 Machine Leaking

• Leaking chemical hose or pump seal: Have these parts replaced by a technician.

• Leaking from door seals: Ensure doors are properly aligned and sealed.

💦 Water Splashing from Doors

• Missing spray nozzles or end caps: Replace immediately.

• Blocked wash nozzles: Clean according to your operator’s manual.

• Arms not rotating: Bearings may need replacement.

• Twisted door handle: Adjust or replace the handle.

🍽️ Poor Washing Results

• Low detergent or faulty dispenser: Check with your detergent supplier.

• Food buildup in wash tank: Pre-rinse and scrape dishes before loading.

• Clogged wash arms or low wash temperature: Clean components and verify heating.

• Incorrect rack loading: Avoid overloading racks to ensure proper spray coverage.

⚙️ Motor Won’t Run

Likely due to a broken contactor or motor—service required from an authorized technician.

🚰 Filling with Water Continuously

Usually caused by a stuck fill valve. Clean or replace as needed.

💧 No or Low Water Supply

• Main water supply off: Turn on facility’s water source.

• Drain or overflow tube misaligned: Clean, reseat, or replace.

• Defective fill valve: Contact your technician or chemical supplier.

🚿 Poor or No Rinse

• Pressure regulating valve issue: Clean or replace valve.

• Clogged rinse nozzles: Clean with a deliming agent or paper clip.

• Improper line size: Use the correct ¾” NPT water line.

🌡️ Low Wash Tank Temperature

• Incoming water too cold: Ensure supply water is at least 140°F (60°C).

• Faulty thermometer or solenoid valve: Have replaced by a technician.

🔄 Wash Arms Not Rotating

• Dirty nozzles or worn bearings: Clean and replace bearings as needed.

• Low water pressure: Check facility pressure and adjust.

🔻 Poor Pumped Spray Pressure

• Clogged spray pipe or intake screen: Clean as directed.

• Low water level or timer issues: Technician service may be required.

🚛 Rack Conveyor Dishwasher Troubleshooting

Applicable for E-Series Single-Tank 44, 66 PW (Prewash), and 64 Two-Tank models.

🧼 Dishwasher Won’t Run

• Door not closed: Adjust or repair door latch.

• No power: Check the main switch and circuit breaker.

• Rack inserted incorrectly: Reinsert properly.

💧 No or Low Water

• Main water off or PRV set incorrectly: Turn on supply and adjust PRV.

• Clogged solenoid strainer or valve: Clean or replace.

🍽️ Poor Washing Results

• No detergent or low levels: Refill as needed.

• Clogged screens or spray arms: Clean thoroughly.

• Low water temperature: Adjust incoming water or repair thermostat.

⏱️ Wash Cycle Too Long

A faulty 90-second timer may need replacement by a technician.

🔄 Conveyor Won’t Run

Check for obstructions or rack jams on the loading end. Clear any blockages before restarting.

🧺 Undercounter Dishwasher Troubleshooting

Applicable for UH Series models.

🧼 Machine Won’t Start

• Door not latched: Ensure it’s fully shut.

• No power or switch off: Plug in or turn on.

• Extended wash mode active: Turn it off to resume normal operation.

💧 Low or No Water

• Main water off or hose kinked: Turn on water and straighten hose.

• Low pressure (below 20 PSI): Adjust or call a plumber.

• Clogged or faulty solenoid valve: Clean or replace.

• Blown circuit board fuse: Technician service required.

🔻 Low Wash Pressure

• Clogged scrap screen or pump intake: Clean both thoroughly.

🧴 Chemical Not Feeding

• Empty chemical container: Refill.

• Blocked feed tubes or screens: Clean and flush with hot water.

• Kinked or damaged tubing: Straighten or replace.

• Blown fuse: Have a technician inspect and replace if needed.

🍽️ Poor Cleaning Results

• Hard water: Contact a chemical supplier for treatment options.

• Low water temperature: Maintain 140°F (60°C).

• Faulty detergent injector or thermistor: Technician service required.

• Overloaded racks: Reload properly for better spray coverage.

⏱️ Wash Cycle Too Long

• Cold water supply: Increase incoming water temperature.

• Booster heater issue: Adjust or replace the thermistor.

💦 Water Draining from Idle Machine

• Drain hose loop removed or clamp loose: Reseat and secure the hose.

• Improper venting in facility plumbing: Have a plumber correct the issue.