Open the main drain valve (usually at the base of the unit, marked with a wrench symbol). Let the water run into a bucket until it runs clear. This removes food debris and soapy water that will harden overnight and block nozzles by morning.

Both spray arms pull out of the unit (check your manual — most rotate counter-clockwise or slide). Hold under a sink tap; run water through the spray holes to clear any trapped food or limescale. If holes are blocked, use a pin or soft brush. Reinstall. This takes 3 minutes and prevents 40% of poor wash results.

The coarse filter (top chamber) and fine filter (bottom) trap food debris. Remove by hand (usually press-fit or bayonet). Rinse both under running water; use an old toothbrush on the fine mesh. If particles are stuck, soak in hot water for 2 minutes. Tap dry and reinstall. If the fine filter looks brown or grey, it’s time for a replacement.

Use a lint-free cloth (not paper towel) and warm water only — no chemicals. Wipe the walls, the door gasket (the rubber seal), and the base. This removes any loose food or mineral deposits that could harden or block sensors overnight. Takes 2 minutes.

Heat cycling and moisture create internal corrosion and gasket hardening. Open the door fully; prop it with a kitchen roll if needed. Air drying overnight prevents 80% of mould, gasket failure, and pump bearing corrosion. Even 8 hours of open-door overnight makes a measurable difference to machine lifespan.

Maidaid Evolution and Hobart models have a built-in timer on the touchscreen that reminds you (usually a beeping alarm or on-screen message every 5-7 days). Halcyon Amika and Winterhalter show a descale prompt when the timer expires. Meiko M-iClean U models auto-run a descale cycle at preset intervals. Classeq requires manual scheduling. Check your manual or contact the manufacturer to confirm your unit’s setting.

Do NOT experiment. Use only your machine’s specified descaler: Halcyon Amika machines use Halcyon Descaler (liquid, 2-litre bottle); Maidaid Evolution use Maidescale tablets (one tablet per cycle); Hobart use Hoba Descaler; Winterhalter use A6 Descaler (1 litre) or A7 (concentrate); Meiko use EcoBrite Descale; Classeq use Classeq Descaler tablets. Pour or insert per your machine’s descale compartment (usually marked DESC or CHEM 2 on the control panel).

Select “Descale” or “Clean Cycle” from your touchscreen menu (Maidaid: hold the “Clean” button for 3 seconds; Hobart: select CleanCycle from the main menu; Halcyon: select Maintenance > Descale; Winterhalter: select Service > Descale). The cycle typically runs 25–35 minutes with no load in the chamber. The machine will heat the descaler and pump it through all internal passages to dissolve mineral deposits.

Once the descale cycle finishes (it will beep or show “Descale Complete”), immediately run a full empty rinse cycle (select Rinse Only or Pre-Wash, no load) to flush any remaining descaler residue. This prevents descaler taste or smell in the next load and ensures all nozzles are clear.

Write the date, time, and descaler chemical name on your maintenance checklist. This creates a traceable record that your dishwasher is being serviced to manufacturer standard. In a food safety audit or insurance claim, the lack of a descale log is treated as evidence of negligence.

Buy a hardness test strip (Screwfix, Wickes, or Amazon — £3-£5 for a pack of 10). Fill a glass with tap water, dip the strip for 3 seconds, and compare the colour change to the chart. Record the ppm or degree reading. If it shows hard water (>300 ppm) and you’re currently descaling every 2 weeks, increase frequency to weekly. If it shows soft water (<100 ppm) and you're descaling every week, reduce to every 4 weeks. This simple test saves you £50/month in unnecessary chemicals and prevents over-descaling, which can damage seals over time.

This is your HACCP evidence. Place a food-safe thermometer (digital or mercury) inside a cup or beaker, close the door, and run a rinse cycle. The temperature reading at the end of the cycle must be ≥82°C. Write the date, time, temperature, and “PASS” or “FAIL” on your log. If it’s below 80°C, the rinse boiler is likely scaled and needs descaling immediately (or has failed). If it’s consistently 78–81°C, your descale intervals may be too long for your water hardness.

Open the door fully and look at the rubber seal all the way around. Run your thumb along it. If you feel cracks, see any torn sections, or if the rubber feels rock-hard (not supple), the gasket is nearing end of life. A leaking gasket floods the base and ruins the electronics. Replacement cost £80-£140 and takes 10 minutes. It’s worth replacing early rather than dealing with a catastrophic flood during service.

Locate your external water filter housing (usually on the inlet line to the machine, marked with a blue/red handle or visible cartridge). Turn the handle counter-clockwise; slide out the old cartridge (it will be brown or grey if it’s working). Replace with a new cartridge (cost £30-£50 depending on brand). Turn the handle clockwise until snug. In hard water, do this every 4 weeks. In soft water, every 8 weeks. A clogged filter reduces water pressure and forces the machine to heat less efficiently.

Most machines have a small window or indicator on the detergent and rinse aid reservoirs. Check that the level is midway or above the minimum line. If either is low, refill. If either empties very quickly (within 2-3 days of heavy use), the peristaltic tube may be worn and not regulating dose properly. Worn tubes waste £20-£40 per month in chemicals and need replacement (£40-£80 labour + parts).

Spray jet nozzles (clean or replace if blocked); pump bearings (listen for noise); rinse boiler thermostat (verify it cuts off at the right temperature); heat recovery system if fitted (clean or replace filter); detergent/rinse aid peristaltic tubes (look for cracks); door gasket and hinge movement; water inlet valve pressure and flow.

A preventative engineer visit typically costs £120-£180 and takes 45 minutes. If the engineer finds worn components (tubes, gasket, nozzles), those are separate costs and labour. Total quarterly cost = £120-£180 + occasional parts (average £60 per visit). Much cheaper than a £400 emergency rinse boiler repair on a Friday night when you’re fully booked.

Call your service provider at the start of each quarter and book a date that suits your quiet service (usually a Monday or Tuesday lunch). Ask for a service certificate at the end of the visit — this is your evidence of preventative maintenance for insurance and HSE compliance records. Keep all certificates in a folder.

Under the Electricity at Work Regulations 1989, all commercial electrical appliances (including dishwashers) must be formally tested annually. Contact your local PAT testing company (many electricians or catering equipment providers offer this). Cost £30-£60. The test takes 10 minutes and involves electrical safety checks — earth continuity, insulation, and leakage current. You’ll receive a pass/fail certificate.

If you have a service contract (annual fees ranging £200-£500 depending on response time and parts cover), review the terms. Does it include preventative engineer visits? Emergency call-outs? Parts cover? Does the price need to escalate? If the machine is 8+ years old and still original, consider whether parts cost (older machines have expensive obsolete parts) and the probability of major failure make a replacement worth evaluating.

The seals on the rinse boiler heating element can harden and fail around year 5-6 of use. If your machine is approaching that age, ask your engineer to inspect them. Replacement is a £150-£300 job but prevents a catastrophic leak that will wreck the control board (£500+ damage). It’s worth doing this proactively at year 5 if you plan to keep the machine for another 5 years.

Keep 12 months of: descale logs, temperature records, water filter replacement receipts, engineer service certificates, and the most recent PAT test certificate. In a food safety inspection, HSE visit, or insurance claim, you need to show you’ve maintained the equipment to manufacturer standard. A missing PAT certificate or no descale logs will be flagged as non-compliance.

Impact: Water and food debris sit overnight; by morning, soapy water has hardened and the pump inlet is clogged. First wash of the day is weak or incomplete. Fix: Make drain + air-dry part of the closing checklist and assign it to a specific person.

Impact: Incompatible descaler can damage seals, etch stainless steel, or leave residue. Warranty void; repair cost £200+. Fix: Confirm your brand (logo on control panel) and order only that brand’s descaler.

Impact: In a food safety audit, no log = no evidence. Auditor will flag non-compliance. Insurance may not cover equipment failure if maintenance cannot be proven. Fix: Print a simple log sheet; laminate it; clip it next to the machine; take 30 seconds daily to fill it in.

Impact: Early warning sign of limescale buildup. By the time temperature reaches 75°C, the boiler is heavily scaled and a failure is days away. Fix: Check temperature weekly; if below 82°C, run a descale cycle immediately (don’t wait for the scheduled weekly descale).

Impact: Liquid seeps into the electrical housing, corrodes circuit boards, and kills the machine. Repair cost £300-£500. Fix: Use only food-safe, stainless steel-safe exterior cleaner. Wipe dry immediately.

Impact: After 8 weeks in hard water without replacement, the filter is fully clogged. Water pressure drops; heating time increases; energy bill rises. Machine strains and pump bearings wear. Fix: In hard water (>300 ppm), replace every 4 weeks. In soft water, every 8 weeks. Set a calendar reminder.

Impact: Water leaks under the door; floods the electrical base; corrodes the control board in hours. Catastrophic failure mid-service. Fix: If you see a crack or hardening, order replacement (£80-£140) and fit it before the next service. Early replacement costs £140; post-failure board replacement costs £500+.

Impact: Excessive descale in soft water can damage rubber seals and degrade the heating element prematurely. Fix: Test water hardness monthly. If hardness is <100 ppm (soft), descale only every 4 weeks, not weekly. Over-descaling is as harmful as under-descaling.