Thereâs no worse start to service than a machine that wonât get up to temperature. No hot water, no steam, and a queue starting to form â itâs one of the most common calls we get from cafĂŠs and restaurants across London, and in most cases the cause is one of a handful of usual suspects.
Before you panic and start pulling the machine apart, hereâs whatâs actually going on when a commercial espresso machine wonât heat, whatâs safe to check yourself, and where itâs time to stop and call in an engineer.
First, rule out the obvious
It sounds basic, but it catches out more sites than youâd think:
- Check the isolator switch and fuse. Commercial machines are usually wired to a dedicated isolator or spur. If itâs tripped, the machine may power on (lights, display) but never actually heat, because the heating element sits on a separate circuit or a blown fuse has cut power to it specifically.
- Check the water supply is actually on. Many machines will refuse to heat, or will heat briefly then cut out, as a safety measure if they canât detect water reaching the boiler. A closed stopcock after cleaning or a building water shut-off is a surprisingly common cause.
- Look for an error code or warning light. Most modern commercial machines (La Marzocco and similar) will flag a heating fault with a specific light pattern or digital error code rather than failing silently. Itâs worth a photo before you call anyone â it saves diagnostic time.
The most common real causes
If the basics check out and the machine still wonât heat, itâs almost always one of these:
A faulty heating element. Elements do wear out, particularly on high-volume machines running long hours. This isnât something to test yourself â a failed element can trip breakers repeatedly or, in rare cases, pose a real safety risk if worked on live.
A tripped or failed thermostat / pressurestat. These components regulate boiler temperature and pressure and are common failure points, especially on machines that are a few years into service. A failed pressurestat often causes the machine to either overheat and trip out, or never reach temperature at all.
Scale build-up in the boiler. In hard water areas (most of London included), limescale insulates the heating element from the water itâs meant to be heating, forcing it to work harder and eventually fail. This is one of the most preventable causes of heating faults â regular descaling and proper water filtration make a measurable difference, which is exactly why service intervals exist. If youâre not sure how due your machine is for one, our guide on how often a commercial coffee machine should be serviced covers what a sensible schedule looks like.
A failed control board. Less common, but on machines with electronic boiler management, a board fault can prevent the heating cycle from ever triggering, even though every other component is fine.
Whatâs safe to check yourself, and what isnât
Checking the isolator, the water supply, and looking for an obvious error code is safe and sensible â do that first. Opening the machine to inspect the element, thermostat, or wiring isnât, both for your safety and the machineâs. Commercial espresso machines carry mains voltage into a wet environment, and incorrect intervention can turn a straightforward repair into a much bigger (and more expensive) one.
If a service reset doesnât bring the machine back and youâve confirmed power and water are both getting to it, thatâs the point to stop and call an engineer rather than keep troubleshooting.
If youâre mid-service and the machine has just died
A heating fault during trading hours is exactly what our emergency callout service exists for. We cover engineers across London and the surrounding areas, and a fast, correct diagnosis usually means the difference between a same-day fix and a machine sat out of action for days.
For everything else â routine servicing, descaling, and the kind of preventative maintenance that stops heating faults happening in the first place â our machine servicing plans are worth a look before the next fault finds you.
Machine not heating right now? Get in touch and weâll get an engineer scheduled.