Listen to the coffee machine before you touch anything
With no coffee coming out of the coffee machine, the first clue is sound. A fully automatic machine makes a drink in stages: it grinds, the brew unit closes around the coffee, the pump pushes hot water through, and the spouts deliver. Which stage goes quiet or runs on without result points you at the part of the path that is blocked.
Make one drink with a cup in place and stay beside it. Note whether you hear grinding, a brief motor sound as the brew unit moves, and the steady buzz of the pump, and write down any message the moment it appears.
Nothing happens at all
No grinding and no pump usually means the machine is waiting for something: water, beans, an emptied grounds container, a closed door or the end of its heat-up. The display normally says which, and those messages are covered in the guide to reading the display.
Grinding and pumping, but an empty cup
The machine believes it is making coffee. Water is either not arriving, not getting through the coffee, or leaving by another route, often straight into the grounds container or the drip tray.
A few drops, then nothing
A trickle that dies away is the classic sign of a grind too fine for the beans or of heavy scale. It is also what a brew unit clogged with old coffee produces.
When no water reaches the coffee
Most empty cups start at the tank. Miele shows a message asking you to push the container in until it engages when the tank is not seated, and Bosch lists a wrongly inserted tank, a float stuck inside it, sparkling water and a new filter that was never rinsed among the reasons its built-in asks for still water.
Air trapped in a filter cartridge behaves like an empty tank. Bosch's remedy is to hold the filter under water until no more bubbles rise, then refit it; a filter pushed in at an angle will not seal against the tank connection either.
- Lift the tank out, check the float moves freely and the tank is clean, then push it back until it seats.
- Fill with cold, still tap water, never sparkling water.
- Rinse a new filter as its instructions describe, or run one test without it.
- Check the tank outlet valve for a coffee ground or a flake of scale.
On a plumbed coffee system
Miele's built-ins that fill from the house supply show a message to check the water intake when the flow is short. Its manual asks you to look for a kinked intake hose and a supply valve that is not fully open. If the machine is set to fill from a water line that is not actually connected, it can sit on its heat-up message indefinitely, so the water setting has to match how the unit was installed.
Source: Miele — CVA 6405 built-in coffee system, operating and installation instructions — Tank not engaged message; check water intake for a kinked hose or a valve not fully open; a water-line setting with no line connected leaves the heat-up message on; loose or damaged cap on the main dispenser connector reduces coffee; F73 check brew unit, clean it or switch off for 2 minutes; demo mode; drink stopped if continue is not confirmed within 5 minutes; Bosch — BCM8450UC built-in coffee machine, use and care manual — Still-water message from a wrongly inserted tank, stuck float, carbonated water, unrinsed or airlocked filter; dispensing slows to a trickle from too fine a grind, heavy limescale or a soiled brewing unit; blocked beverage outlet or connections; switch off 30 minutes when the machine is too hot
A grind so fine the water cannot pass
JURA's troubleshooting table reads almost like this guide's title: coffee that only comes out in drips means the coffee is ground too finely and is blocking the system, and the water hardness may be set wrong. Its answer is a coarser grind and a descaling run.
Bosch says the same of a drink that slows to a trickle or stops completely, adding a heavy build-up of limescale and a soiled brew unit. Move the grind one step coarser, make two drinks, and only then decide whether it helped.
Source: Bosch — BCM8450UC built-in coffee machine, use and care manual — Still-water message from a wrongly inserted tank, stuck float, carbonated water, unrinsed or airlocked filter; dispensing slows to a trickle from too fine a grind, heavy limescale or a soiled brewing unit; blocked beverage outlet or connections; switch off 30 minutes when the machine is too hot; JURA — E8 instructions for use — Coffee only in drips: ground too finely, water hardness may be set wrong, set a coarser grind and descale; ERROR 2 or ERROR 5 after long exposure to cold, warm the machine at room temperature
The spout connector and the brew unit
When the sounds are normal but only a little coffee reaches the cup, look where the coffee leaves the brew unit. Miele connects exactly this pattern, together with more coffee-colored water than usual in the waste container, to the silicone cap on the main dispenser connector: seated loosely, damaged or missing. Its fix is to grease the cap with the supplied silicone grease or fit the spare.
Bosch traces drinks that will not dispense at all to a blocked beverage outlet or one of its three connections. Take the outlet apart as the manual shows and rinse each piece.
When the display asks you to check the brew unit
On a Miele built-in, F73 or a check-the-brew-unit message means the unit cannot move to its position or is too dirty to handle the coffee. If it comes out, clean it and reset it as the manual describes. If it will not come out, switch the machine off, wait two minutes and switch it back on; forcing it is how a repairable problem becomes a broken part.
Source: Miele — CVA 6405 built-in coffee system, operating and installation instructions — Tank not engaged message; check water intake for a kinked hose or a valve not fully open; a water-line setting with no line connected leaves the heat-up message on; loose or damaged cap on the main dispenser connector reduces coffee; F73 check brew unit, clean it or switch off for 2 minutes; demo mode; drink stopped if continue is not confirmed within 5 minutes; Bosch — BCM8450UC built-in coffee machine, use and care manual — Still-water message from a wrongly inserted tank, stuck float, carbonated water, unrinsed or airlocked filter; dispensing slows to a trickle from too fine a grind, heavy limescale or a soiled brewing unit; blocked beverage outlet or connections; switch off 30 minutes when the machine is too hot
Modes that look like a broken machine
A few states stop coffee with nothing wrong at all. Checking them takes a minute and can save a visit.
- Demo mode: Miele notes the display lights while the machine neither heats nor makes drinks.
- An overheated machine: Bosch asks you to switch off for 30 minutes when it says the machine needs to cool.
- Cold storage: JURA shows ERROR 2 or ERROR 5 after a long spell in the cold and asks for the machine to warm up at room temperature.
- A tank that ran dry mid-drink: Miele stops the drink if you do not confirm the continue prompt within five minutes after refilling.
Source: Miele — CVA 6405 built-in coffee system, operating and installation instructions — Tank not engaged message; check water intake for a kinked hose or a valve not fully open; a water-line setting with no line connected leaves the heat-up message on; loose or damaged cap on the main dispenser connector reduces coffee; F73 check brew unit, clean it or switch off for 2 minutes; demo mode; drink stopped if continue is not confirmed within 5 minutes; Bosch — BCM8450UC built-in coffee machine, use and care manual — Still-water message from a wrongly inserted tank, stuck float, carbonated water, unrinsed or airlocked filter; dispensing slows to a trickle from too fine a grind, heavy limescale or a soiled brewing unit; blocked beverage outlet or connections; switch off 30 minutes when the machine is too hot; JURA — E8 instructions for use — Coffee only in drips: ground too finely, water hardness may be set wrong, set a coarser grind and descale; ERROR 2 or ERROR 5 after long exposure to cold, warm the machine at room temperature
