A commercial dishwasher that fails mid service is nearly always water in, water out, heat or chemical delivery, and you can keep trading legally by sanitising at 77 degrees C for 30 seconds or in 50 ppm chlorine.
Skai Solutions answers the phone for restaurants, cafes and takeaways in Australia and New Zealand, so we hear a lot of kitchens in the middle of a bad night. Most pages on this symptom are written to sell you a service call. This one is ordered the way the problem actually presents, by what the machine is doing, and it starts with the thing nobody tells you: you are allowed to keep serving, and there are published numbers for how.
Almost every fault on an under-bench or passthrough machine is one of four systems, and the symptom tells you which one before anyone opens a panel. Find your symptom in the left column.
| What it is doing | System at fault | Check this first |
|---|---|---|
| Not filling, not holding water, fills slowly | Water in | Isolation valve under the bench, strainer in the inlet hose, solenoid buzzing but not opening, building pressure during a busy service |
| Not draining, standing water in the tank | Water out | Scrap filter, drain pump impeller, kinked waste hose, blocked air gap, grease at the trap |
| Not getting hot, not reaching temperature, not getting to temp | Heat | Booster element and its thermostat, a tripped high-limit cut-out, incoming water that was already cold, scale on the element |
| Not priming, not pulling detergent or rinse aid, detergent pump not working | Chemical delivery | Empty drum, cracked or crimped pick-up tube, air in the line, a squeeze-tube peristaltic pump whose tube has flattened |
| Not rinsing, not spraying, not spinning, not cleaning properly | Wash and rinse distribution | Blocked jets in the wash and rinse arms, arm not seated after cleaning, debris in the wash pump |
| Not starting, not turning on, dead panel | Power and interlocks | Breaker, door interlock switch, the machine's own thermal reset, and whether anything else on that circuit also died |
| Will not stop running, cycle never ends | Sensing | Level sensor or pressure switch reading wrong, usually scale or debris on the probe |
Two of those columns are things your own team can clear in ten minutes: the scrap filter and the spray arm jets. Blocked jets are the single most common cause of "not cleaning properly", and the usual reason is that someone washed the arms and put them back without seating them.
Yes, and this is the part that keeps your doors open tonight. The obligation in the Australia New Zealand Food Standards Code is that eating and drinking utensils are cleaned and SANITISED. It is not an obligation to own a working dishwasher. Food Standards Australia New Zealand's cleaning and sanitising guidance, which cites Standard 3.2.2 clauses 19 and 20 and Appendices 6 and 8, sets out the alternatives with numbers on them.
Two practical notes. A three-sink set up (wash, rinse, sanitise) is what those numbers assume, and if you only have two sinks you are using the chemical option, not the heat one. And 77 degrees is hotter than most venue hot water arrives at, which is a separate problem covered on what to do when a restaurant has no hot water. If temperature control on food is also affected, the holding rules are on the 2 hour 4 hour rule.
Worked example, our arithmetic, inputs shown. A dinner service that puts 300 items through the machine takes roughly two extra staff hours to wash, rinse, sanitise and air dry by hand, because the sanitise step adds a dwell nobody can hurry. On the Restaurant Industry Award MA000119 rates in the Fair Work Ombudsman's pay guide published 24 June 2026, a kitchen attendant grade 1 is level 1 at A$26.44 an hour ordinary, A$33.05 Saturday and A$39.66 Sunday. So two hours is about A$53 on a weekday, A$66 on a Saturday and A$79 on a Sunday, before superannuation.
Put that next to a repair. Three nights of a Friday to Sunday weekend is roughly A$212 in extra wages on those rates. A technician who can come Monday and charge a few hundred dollars is cheaper than a fourth weekend, and a machine that fails twice in a quarter is telling you something that a call-out will not fix. New machine pricing, if that is where this is heading, is on commercial dishwasher cost in Australia.
Four of them, and all four get machines replaced that did not need replacing.
Four triggers. Anything electrical past a breaker reset, because warewashers combine water and three phase and that is not a place to experiment. Anything that needs the machine opened while plumbed. Any repeat of the same fault inside a month, which is a symptom rather than a fault. And anything where the temperature gauge and an independent thermometer disagree, because then you do not know what the machine is doing and you cannot prove sanitising to an inspector.
Have four things ready when you ring: make and model off the data plate, the exact symptom in the words of the table above, what you have already checked, and whether the fault is intermittent or constant. That turns a diagnostic visit into a repair visit, which is usually the difference between one call-out and two. Running cost once it is fixed sits in restaurant electricity cost and restaurant water bill cost.
The same line sits further along the kitchen, and on a gas appliance it is drawn by licence rather than by common sense. Our page on a commercial oven that will not heat up covers who may legally open one.
If you are a cafe with a glasswasher, an espresso machine and twelve covers of crockery a sitting, the hand wash fallback above is not an emergency measure, it is a viable permanent arrangement, and a service contract on a machine that small is money you can spend elsewhere. The venues that genuinely need a same-day technician are the ones where a single service puts hundreds of items through and there is no bench space to air dry them.
If the machine that has stopped is under the bar rather than in the kitchen, the fault list is different. We have written both up: why a commercial ice machine stops making ice and how a commercial glass washer works and what breaks on it.
Badly, which is the hidden cost. The hour your chef is on hold to a service company is an hour nobody is answering bookings, and a kitchen in triage does not pick up at all. Skai Solutions answers the phone for restaurants, cafes and takeaways in Australia and New Zealand, takes the booking or the order, and puts it where your team will see it, with setup taking about five days. If your phone mostly carries enquiries rather than bookings, a basic message-taking plan is the right buy and it is not us.
Why is my commercial dishwasher not getting hot?
Four causes in order of likelihood: scale on the booster element, so it cannot transfer heat while still drawing current; a failed element or its thermostat; a tripped high-limit cut-out that needs a manual reset; or incoming water that was already cold because the venue's hot water supply is the real fault. Check an independent thermometer against the machine's own gauge before buying parts.
Can a restaurant trade if the dishwasher is broken?
Yes. The Food Standards Code obligation is that utensils are cleaned and sanitised, not that you own a working dishwasher. FSANZ sets out the alternatives: soak in very hot water at 77 degrees C for 30 seconds, or use 50 ppm chlorine, which is 5 ml of commercial bleach or 12.5 ml of household bleach in 10 L of water, or 70% alcohol, or a commercial sanitiser per its instructions. Air drying is best.
Why is my commercial dishwasher not draining?
Start with the scrap filter, then the drain pump impeller, then the waste hose for kinks, then the air gap, then grease at the trap. A drain pump straining against a greased waste line sounds exactly like a pump about to fail, and replacing the pump will not fix it. If grease management is behind schedule, that is the first thing to deal with.
Why is my dishwasher not pulling detergent?
Chemical delivery faults are nearly always outside the machine: an empty drum, a cracked or crimped pick-up tube, air in the line, or a peristaltic pump whose squeeze tube has flattened with age. Those tubes are a consumable and are usually cheap. Check the drum and the tube before anyone quotes you on a doser.
What temperature does a commercial dishwasher need to sanitise?
For hand sanitising, FSANZ states 77 degrees C for 30 seconds by immersion. For a machine, the guidance does not publish a temperature, only that you should use a dishwasher that can sanitise, on the longest hottest cycle or the program designed for sanitation, with the right detergent or sanitising chemical. Follow the machine's own manufacturer's instructions.
How much does it cost to wash up by hand for a service?
On our arithmetic, roughly two extra staff hours for a 300 item dinner service because the sanitise step adds a dwell. At Restaurant Industry Award MA000119 rates applying from 1 July 2026, a kitchen attendant grade 1 is A$26.44 an hour ordinary, A$33.05 Saturday and A$39.66 Sunday, so that is about A$53, A$66 or A$79 before superannuation.
Is 50 ppm chlorine safe for crockery and glassware?
It is the concentration FSANZ publishes for sanitising eating and drinking utensils, with a contact time usually of 10 to 30 seconds, and the manufacturer's instructions take priority over that range. Clean the item first, because sanitiser does not work through food residue, and throw diluted bleach away after 24 hours because it loses strength.