Why Temperature Matters in a Commercial Dishwasher

Commercial dishwashers rely on temperature for two different purposes:

Cleaning

The wash cycle uses heated water together with detergent to help remove food residue, grease and proteins from dishes.

Sanitising

Many commercial dishwashers also use a high-temperature final rinse to achieve thermal sanitising, while some models rely on chemical sanitising instead. The required operating temperatures therefore vary depending on the machine's design and the manufacturer's specifications.

Because different commercial dishwashers operate differently, temperature problems should always be assessed in accordance with the manufacturer's recommendations.

Why Isn't My Commercial Dishwasher Reaching Temperature?

Several different faults may prevent a commercial dishwasher from heating correctly.

Common possible causes include:

• Heating element problems

• Booster heater faults

• Temperature sensor faults

• Thermostat problems

• Scale build-up

• Electronic control faults

• Water supply issues

• Wash tank heating problems

• Incoming water temperature

• High-volume operation exceeding recovery capacity

Correct diagnosis is important because several different faults may produce similar symptoms.

Common Causes Explained

Heating Element Problems

Commercial dishwashers use heating elements to heat the wash tank and, on many models, a separate booster heater for the final rinse.

If a heating element develops a fault, the dishwasher may struggle to reach its intended operating temperature.

Booster Heater Problems

Many commercial dishwashers use a dedicated booster heater to raise rinse water to the temperature required by the manufacturer.

If the booster heater cannot reach its operating temperature, the dishwasher may delay the rinse cycle, display a fault code or produce poorly sanitised ware depending on the machine's programming.

Temperature Sensor Problems

Temperature sensors continuously monitor water temperature throughout the wash cycle.

If a sensor provides inaccurate readings, the control system may not heat the machine correctly even if the heating elements are functioning.

Thermostat Problems

Some commercial dishwashers use thermostats to regulate heating.

A faulty thermostat may prevent the machine from heating correctly or cause heating to stop prematurely.

Scale Build-Up

Mineral deposits from hard water can accumulate on heating elements over time.

Scale acts as an insulating layer, reducing heating efficiency and increasing the time required to reach operating temperature. Regular descaling and preventative maintenance help reduce this risk.

Electronic Control Problems

Modern commercial dishwashers rely on electronic control systems to coordinate filling, heating, washing and rinsing.

If the control system develops a fault, heating performance may be affected even though individual components remain operational.

High-Volume Operation

During busy service periods, some commercial dishwashers may require time for the rinse boiler to recover between cycles. Machines with lower heating capacity can take longer to restore rinse temperature under continuous heavy use. The recovery characteristics vary between manufacturers and machine sizes.

Signs Your Commercial Dishwasher Isn't Reaching Temperature

You may notice:

• Dishes remain greasy.

• Glasses come out cloudy.

• The machine takes much longer to heat.

• Wash cycles are delayed.

• Temperature alarms appear.

• Error codes are displayed.

• Dishes remain unusually wet after washing.

• Cleaning performance has declined.

These symptoms may have several different causes.

Safe Checks Before Booking a Repair

Before arranging a service visit, operators can safely check:

✔ The dishwasher has completed its full cycle.

✔ The machine has adequate water supply.

✔ Filters are clean.

✔ No obvious error codes are displayed.

✔ The machine has had sufficient time to heat after switching on.

✔ Daily cleaning has been carried out.

Do not dismantle heating systems, electrical panels or thermostats.

Commercial dishwashers contain electrical heating components that should only be serviced by appropriately qualified technicians.

Why Professional Diagnosis Matters

A commercial dishwasher that's not reaching temperature doesn't automatically require a new heating element.

The same symptom may result from:

• booster heater problems

• temperature sensors

• thermostats

• scale build-up

• electronic controls

• water supply issues

• wash tank heating faults

Although the dishwasher behaves the same way, the required repair can be completely different.

Professional diagnosis helps identify the underlying cause before replacement parts are fitted, reducing unnecessary repair costs and downtime.

Not Heating vs Not Reaching Temperature – What's the Difference?

Many operators assume these faults are the same, but they often describe different problems.

A dishwasher that is not heating may produce cold water throughout the cycle.

A dishwasher that isn't reaching temperature may still heat the water, but not to the level intended by the manufacturer. This can lead to longer cycle times, poor cleaning performance or reduced sanitising effectiveness depending on the machine's design.

Understanding this difference helps technicians diagnose the fault more accurately.

Preventing Temperature Problems

Routine preventative maintenance helps identify developing heating problems before they interrupt service.

Preventative servicing may include:

• Inspecting heating elements.

• Testing temperature sensors.

• Checking booster heaters.

• Inspecting thermostats.

• Assessing electrical connections.

• Removing mineral scale where appropriate.

• Verifying operating temperatures against manufacturer specifications.

Regular servicing helps maintain reliable performance and reduce unexpected downtime.

What Happens When You Book a Service?

Step 1 – Tell Us About the Problem

Contact our team and describe the symptoms you've noticed, including whether the machine is displaying any error codes or taking longer than usual to heat.

Step 2 – Professional Diagnosis

One of our experienced technicians will inspect the dishwasher, test the relevant systems and identify the underlying cause of the temperature problem.

Step 3 – Honest Recommendations

We'll explain what we've found, discuss the recommended repair and answer any questions before work proceeds.

We recommend only the repairs your equipment genuinely needs.

Step 4 – Get Back to Business

Our goal is to restore your commercial dishwasher efficiently and professionally so your kitchen can continue operating with minimal disruption.