The short answer
On a Bosch dryer, a dryer that no longer dries a load usually comes down to the machine working as designed rather than anything deeper in the machine: a ventless or compact dryer takes longer than a vented full-size machine by design, so a long cycle is not by itself a fault. That keeps it an owner check first, not a service call. Start here: empty the condensate tank and clean the condenser, because on a ventless Bosch these two are the entire moisture path and both are owner-serviceable.
What you are seeing
- Loads that need two cycles where one used to do
- A cycle that ends early with the load still damp
- Clothes hot on the outside and damp in the middle
- Not this fault: No heat at all, which is a heating fault rather than a performance one
- Not this fault: A drum that does not turn, which is a drive fault
- Body: Bosch builds this dryer as a compact ventless condenser dryer that condenses moisture out of the drum air and collects it in a tank or pumps it to a drain, with a lint filter and a separate condenser unit behind a lower door. That architecture decides which of these you see first.
- Also check note: If these fit better, the fault is a different one.
Likely causes, in order
- The machine working as designed — Why this rank: A Bosch condenser dryer takes longer than a vented machine by design, so a long cycle on this platform is the architecture rather than a fault.
- A blinded lint filter — Why this rank: The Bosch filter is a two-part stack, and a partly seated filter sends lint straight past it into the condenser.
- Lint in the stages beyond the filter — Why this rank: The Bosch lint path runs filter, then condenser, then sump, and cleaning only the first stage blinds the two behind it.
- A restricted exhaust duct — Why this rank: A ventless Bosch has no duct at all.
- Filmed moisture sensor bars — Why this rank: The sensor bars read the load's conductivity, and a fabric-softener film insulates them so the machine believes a wet load is dry.
- Body: Ranked for a Bosch dryer specifically.
What to check, in order
- Body: The order follows the ranking, and the ranking follows the platform. First: compare with the manufacturer's stated cycle behaviour rather than with a previous machine. It goes first because a Bosch condenser dryer takes longer than a vented machine by design, so a long cycle on this platform is the architecture rather than a fault. Second: run water onto the filter; if it pools rather than passing straight through, it is blinded. With the first check clean, this is what the Bosch platform makes next most likely. Third: look into the filter housing with a flashlight after removing the filter. Only after those three is it worth reaching for a restricted exhaust duct: it costs more to get at, and it does not explain the first three coming back clean.
Checks you can make
- Pull the condensate tank out fully, empty it and push it back until it seats with a click. A tank that is not home is the most common source of water on the floor under a Bosch. — Tools: none — Time: about five minutes
- Remove the filter and look into the housing with a flashlight, then open any lower access door and look for a second filter or a finned block behind the first. Clean every stage you find. — Tools: flashlight, vacuum — Time: about twenty minutes
- Open the lower door, release the condenser unit and rinse it under a tap until water runs through the fins freely. Lint there floods the sump and overflows the cabinet. — Tools: none — Time: about twenty minutes
- Body: Stop at the first step that would need a meter on live terminals or a sealed assembly opened.
Before you open anything
Safety
Treat a dryer complaint as a fire question first. Heat, lint and restricted airflow are the combination that starts laundry fires. Unplug the appliance or switch off its breaker before removing any panel. A capacitor can hold a charge after the power is off. Clear the whole duct run, not just the machine end. A restricted duct is the condition behind most dryer heat faults and behind most dryer fires. Never run the machine with the duct disconnected for longer than a brief test, and never vent it into the room.
When to call
The line is not difficulty, it is what the next step costs and risks. Call when: the whole lint path and the duct are proven clear and drying time has not improved the machine gets hot but the load stays wet, which points at airflow rather than heat
What this page omits
This is generalized information: it ranks causes for the Bosch dryer range as one platform, not for a single model. Where a page exists for your specific model it is the more specific one and takes precedence over this. The narrower pages below cover the other presentations of this symptom.
Entries: - [Bosch Dryer: Controls, Display or Error Code](/blog/bosch-dryer-control-fault) - [Bosch Dryer: Water Leak](/blog/bosch-dryer-water-leak)
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
