Commercial Dishwasher Heating Element Not Working: Fix it Now

     

A malfunctioning commercial dishwasher can disrupt kitchen operations and compromise hygiene standards. One of the most critical components responsible for sanitizing dishes effectively is the dishwasher heating element. When this part stops working, water won’t reach the high temperatures needed for proper cleaning, leading to unsanitary conditions and frustrated staff. Fortunately, identifying and fixing the issue is often straightforward when you know what to look for. In this guide, we’ll explore the most common reasons a commercial dishwasher heating element might fail—and how you can troubleshoot and repair it quickly to restore full function to your kitchen equipment.

Common Causes for Commercial Dishwasher Heating Element Not Working and Their Fixes

When a commercial dishwasher heating element stops working, the issue often stems from a handful of common problems. Understanding these causes is key to restoring efficient, reliable kitchen performance.

Burnt-Out Heating Element

Cause:
The heating element itself can burn out due to prolonged use, power surges, scale build-up, or insufficient water coverage that causes overheating. Over time, this leads to cracks or breaks in the element, rendering it non-functional.

Fixes:

• Disconnect the power and water supply to the dishwasher.

• Use a multimeter to check continuity across the terminals. A reading of infinite resistance, or "OL," indicates a faulty element.

• Remove the old heating element (typically located at the base of the tank) and install a new, model-specific replacement.

• Reassemble and test for proper heating in a wash cycle.

Faulty Thermostat or High-Limit Thermostat

Cause:
Thermostats regulate water temperature. If the thermostat is faulty or the high-limit thermostat is tripped, the system may stop sending power to the heating element as a protective measure.

Fixes:

• Test the high-limit thermostat using a multimeter for continuity.

• If tripped, reset the thermostat (some models have a manual reset button).

• If faulty, replace the thermostat with a part compatible with the dishwasher model.

• Ensure proper water fill level and flow to avoid triggering false high-limit conditions.

Defective Heating Relay or Control Board

Cause:
The control board or heating relay acts as the brain of the dishwasher. If it fails, it may not send the signal to activate the heating element even if the element and thermostat are functional.

Fixes:

• Check for signs of burnt or damaged relays on the control board.

• Test the relay function with a multimeter by checking voltage output when the heating cycle should be active.

• Replace damaged relays or the entire control board as needed.

• Always consult the dishwasher’s service manual or wiring diagram before working on electronics.

Water Level or Flow Issues

Cause:
Low water levels in the tank can cause the heating element to overheat and shut down as a protective measure. A malfunctioning water inlet valve, clogged filters, or float switches can restrict water flow, affecting heat function.

Fixes:

• Inspect the water inlet valve for debris or mechanical failure; clean or replace if needed.

• Check and clean the float switch and screens for buildup.

• Ensure proper water pressure from the supply line.

• Test the float switch operation with a multimeter to ensure it signals the control board correctly.

Limescale Buildup on the Heating Element

Cause:
Hard water can lead to mineral deposits forming on the heating element. This buildup insulates the element, reducing heat transfer efficiency and potentially leading to overheating or failure.

Fixes:

• Visually inspect the element for white, chalky scale.

• Use a commercial-grade descaling solution or vinegar soak (with the element removed) to dissolve deposits.

• Install a water softener system or use water treatment chemicals to prevent future buildup.

Blown Fuse or Tripped Circuit Breaker

Cause:
Electrical surges, overloads, or aging wiring can cause internal fuses to blow or breakers to trip, cutting power to the heating system.

Fixes:

• Check the main power supply and internal fuses on the control board or terminal block.

• Reset tripped circuit breakers or replace blown fuses.

• If the problem persists, investigate for short circuits or ground faults in the wiring to the heating element.

Wiring or Terminal Issues

Cause:
Loose, corroded, or burned wiring connections can interrupt the flow of electricity to the heating element. Over time, vibration or heat can loosen terminals or damage insulation.

Fixes:

• Inspect all wire terminals and connections leading to the element, thermostats, and control board.

• Look for signs of discoloration, corrosion, or burning.

• Tighten all connections, replace damaged wires, and secure with heat-resistant connectors.

• Always perform this work with the power disconnected and follow safety guidelines.

Faulty Door Switch

Cause:
If the door switch fails or doesn’t engage properly, the dishwasher won’t activate the heating element as a safety precaution—even if the cycle appears to be running normally.

Fixes:

• Test the door switch with a multimeter to confirm continuity when the door is closed.

• Adjust the door latch if the switch isn’t engaging fully.

• Replace the switch if it is damaged or non-functional.

Incorrect Cycle Settings or Programming Errors

Cause:
Some dishwashers allow manual selection of wash cycles that may not use heated water. Inadvertently choosing a non-heated or energy-saving cycle can give the impression the dishwasher heating element is malfunctioning.

Fixes:

• Double-check the cycle settings on the control panel.

• Run a high-temperature wash cycle to test the heating function.

• Reset or reprogram the control board if necessary, following the manufacturer’s instructions.

Software or Sensor Malfunction

Cause:
Advanced commercial dishwashers often include temperature sensors and software that monitor internal operations. If a sensor malfunctions, it can prevent the heating element from activating due to false temperature readings.

Fixes:

• Use diagnostic mode to check for fault codes (consult the model-specific manual).

• Test the temperature sensor with a multimeter (resistance should change with temperature).

• Replace any faulty sensors and clear error codes from the control panel.

Overloaded Dishwasher or Improper Loading

Cause:
When dishes are overloaded or placed incorrectly, water flow can be obstructed. preventing proper circulation and causing uneven heating. Some units have sensors that detect this and restrict heating to prevent damage.

Fixes:

• Train staff on correct loading patterns (e.g., avoid blocking spray arms or heating zones).

• Avoid stacking large pans or trays over heating elements.

• Run a cycle with no load to test whether the heating resumes under proper conditions.

Low Voltage or Inconsistent Power Supply

Cause:
A commercial dishwasher requires a consistent voltage to operate heating components. Fluctuations in power can cause the element to underperform or shut off intermittently.

Fixes:

• Use a voltmeter to verify the power supply to the unit.

• If voltage is inconsistent, check the building’s electrical system or consult an electrician.

• Install a surge protector or dedicated circuit if required.

Error Codes and Safety Lockouts

Cause:
Many modern commercial dishwashers come with digital displays and built-in diagnostics. If a fault is detected (e.g., overheating, door not sealed, water error), the system may disable heating until the error is resolved.

Fixes:

• Refer to the user manual to decode flashing lights or error messages.

• Follow manufacturer reset procedures.

• Clear the error, restart the machine, and monitor operation.

A commercial dishwasher with a faulty heating element can severely impact your kitchen’s efficiency and sanitation. Fortunately, most issues stem from common causes like a burnt-out element, faulty thermostat, wiring problems, or limescale buildup. With a little troubleshooting and the right tools, many of these problems can be identified and fixed without needing to replace the entire unit. Regular maintenance and timely repairs will not only save money but also prolong the life of your dishwasher heating element. Whether you handle repairs yourself or call a technician, knowing the common issues puts you in control. Keep your kitchen running smoothly and safely.

Written by Allen Rode for PartsFeUK, your trusted source for various high-quality commercial restaurant equipment, including dishwasher heating elements and more.