Commercial Dishwasher Case Study: A Central Kitchen at Three Peaks a Day

A central kitchen feeding a chain catering group washed about 9,000 items a day across three sharp peaks. The hand wash bay was the bottleneck, and it was also the place where the hygiene audit found gaps. We installed a conveyor line with a heat recovery hood, and the peak now runs with one operator instead of four.

Project Snapshot

The Problem: Three Peaks and a Wash Bay That Never Cleared

Central kitchens do not have a steady flow. They have three short, violent peaks when the trays come back from service, and then nothing for two hours.

A hand wash bay cannot absorb that shape. Four people stood at the sinks for forty minutes and then had nothing to do, and the queue still backed up into the corridor at the worst point. Detergent dosing was by eye, so chemical cost moved with whoever was on shift.

The audit problem was different in kind but came from the same place. A hand bay has no rinse temperature record. The kitchen could describe what it did, but it could not produce a number for the auditor.

Why We Chose a Conveyor Line Over More Sinks, Low-Temp Machines and Parallel Hood Units

Add a second hand wash bay. Excluded. It doubles the labour at peak and still leaves the audit gap, because the rinse temperature is not recorded anywhere.

Low-temperature chemical sanitation machines. Excluded. They save energy, but the cycle runs longer to get the same result, and a longer cycle is exactly what a peak cannot absorb.

Several undercounter units in parallel. Excluded. Each one needs its own water, drain and power point, and the kitchen did not have the wall space or the drainage.

One conveyor line with a heat recovery hood. Selected. Continuous flow matches a peak shape, and the machine records its own rinse temperature.

The Machine We Built

The line is a straight-through conveyor with a separate wash and final rinse zone, built for 240 racks an hour on a 90-second cycle. Racks move at a fixed speed, so the output is a property of the machine rather than of how hard the team is working.

The final rinse runs at 82 °C, which is the figure the kitchen's hygiene plan needs to show, and it is logged per shift rather than claimed. Wash water is reused across zones, so the line holds around 2.6 litres per rack.

A heat recovery hood sits over the outfeed. It takes the latent heat out of the vapour rising off clean ware and puts it back into the incoming cold water, which is what keeps the steam out of the room and the gas bill down. The long dragon configuration suits this layout where the tabling runs straight through the wall.

Installation: How the Work Ran

Installation was planned around the service, not around the builder. The old bay stayed in use until the Friday, and the new line was commissioned over a single weekend.

Position and levelling took the first day, and services took the second, because the drainage had to be moved about four metres. The third day was dry cycles and temperature verification, the fourth was training with real trays, and the fifth was a supervised service running live volume.

Water treatment was set at the same time. The site supply is hard, so a softener was sized to the line rather than to the building, which is what protects the rinse jets and the heater.

Testing and Quality Control

Every machine is run on the test bay before shipment. Wash and rinse temperatures, pump pressure, rack transport speed and door interlocks are recorded against the build sheet.

On site, commissioning verified the rinse temperature with a separate probe rather than trusting the machine display, and the reading was logged over a full peak. Rack output was counted against a stopwatch on three separate peaks.

Detergent and rinse aid dosing was set by titration, not by feel. That is the single change that made chemical cost stable between shifts.

Results: What the Numbers Show

The peak now runs with one operator loading and one unloading, against four people at the sinks before. Trays clear the wash area inside the peak window instead of queueing into the corridor.

Water settled at about 2.6 litres per rack, and detergent cost stopped moving with the shift because dosing is metered. The rinse temperature record closed the audit finding without any extra paperwork.

Steam left the room with the heat recovery hood, which the ventilation engineer had flagged as a separate problem. The HACCP-aligned warewashing routine is now part of the kitchen's daily record.

What This Case Means for Your Project

Warewashing fails on shape, not on volume. A kitchen that washes 9,000 items in three bursts needs a machine that moves continuously, not a bigger sink.

Send us your item count per peak, the tray and rack sizes, and the water hardness at the site. We will size the line, draw the tabling into your existing layout and quote the installation with commissioning included. Our conveyor systems cover most central kitchen layouts, and you can brief our project team on your floor plan directly.