My commercial dishwasher/glasswasher isn't cleaning properly — what do I check before calling out a tech?
My café's commercial dishwasher/glasswasher has stopped cleaning properly — glasses come out filmy, spotted or greasy, not clean. Before I lose service and call an engineer, I want to triage it.
- What are the usual causes I can check myself — spray arms, wash/rinse temperature, detergent/rinse-aid, scale, filters?
- What's the point where it needs a proper repair (not DIY)?
- Anything specific to a busy commercial machine?
Trying to sort the quick wins fast (a café can't run without clean glasses) and know when to make the call. Where do I start?
3 answers
Short answer: filmy or spotted glasses from a commercial washer are usually one of a handful of check-it-yourself things — blocked spray-arm jets, wrong or empty detergent/rinse-aid, wash or rinse water not hot enough, a clogged filter, or LIMESCALE from hard water furring everything up. Work through those first; call a tech when it's the heating element, pump, thermostat or a scaled-up machine that needs descaling/parts.
Check these yourself, in order: 1. Spray arms & jets — pull them and check the little holes aren't blocked with scale or debris. Blocked jets = poor coverage = dirty/patchy results. Spin freely? 2. Detergent & rinse-aid — are both dosing and not empty? No rinse-aid = spotting and filming (rinse-aid is what sheets the water off for spot-free glasses). Wrong detergent for a commercial machine also fails. 3. Temperature — commercial machines rely on a hot wash and a hotter rinse (a proper sanitising rinse temperature). If the water isn't getting hot enough, it won't clean or sanitise — that can point to a heating/thermostat fault. 4. Filters & wash tank — clogged filters or dirty wash water recirculating grease onto your glasses. Clean them; change the water. 5. Limescale (big one in the UAE) — hard water furs up the element, jets and internals, killing performance. The machine needs regular descaling; badly scaled ones need a proper service. (Same hard-water problem softeners tackle.)
Call a refrigeration/appliance tech when: the water won't heat (element/thermostat), the wash/rinse pump is weak, or it's so scaled it needs a proper descale and parts.
Commercial-specific: it's also a hygiene point — a machine not reaching rinse temperature isn't sanitising, which matters for a food business, so don't limp it along. Quick wins first (arms, rinse-aid, filters, descale); if those don't fix it, get a commercial kitchen-equipment tech before service suffers. F&B folks — how often are you descaling yours?
The scale and rinse-aid ones are the most common "it's not cleaning" calls that turn out to be non-faults. In hard-water areas the machines fur up fast, so a descaling schedule is basic PM — skip it and performance drops then the element dies early. And an empty rinse-aid causes exactly the "spotted/filmy glasses" complaint that people assume is a breakdown. Check the cheap consumables and descale before assuming the machine's broken; it usually isn't. Keeping a maintenance schedule on it beats emergency call-outs mid-service.
Not commercial, but the hard-water link jumps out — the same limescale that wrecks everything else obviously clogs a dishwasher's jets and element too. Makes sense that descaling is half the battle here. Even on a home machine the "spotty glasses = need rinse aid + descale" fix is true. Sounds like in this water, any washing machine or dishwasher lives or dies on how well you keep the scale off it.
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