Bosch Dryer Repair in Toronto — Not drying (clothes still damp)

• Diagnose by platform first — "not drying" is three different repairs on a Bosch, and the part numbers do not cross over. On the condensation WTG86 (badged 300 Series in NA: WTG86400UC / WTG86402UC) the heat is recycled through a MANUAL heat-exchanger the owner is supposed to rinse on a schedule nobody was told about; on the heat-pump WTW87 (500 Series: WTW87NH1UC) and WQB245 (800 Series: WQB245AXUC) the condenser SELF-cleans, so on those the damp-finish complaint shifts to the fluff filters and the condensate path instead. We confirm which machine by serial before we quote, because a manual-rinse fix on a WTG86 and a filter/drain fix on a WTW87/WQB245 are not the same call.
• The single most common damp-clothes call across all three Bosch platforms is the MOISTURE SENSOR, not the heater. The AutoDry program reads dryness off two stainless-steel sensor bars at the lint-filter mouth; Bosch's own WTG86400 manual states a fine layer of limescale forms on the moisture sensors over time and must be removed regularly. In GTA hard water the sensor bars film over fast, the control reads the load as already dry and ends the cycle early — clothes come out damp on a machine that is otherwise healthy. We wipe the bars with white vinegar (never steel wool — Bosch's manual warns it damages the stainless sensor) and re-run an AutoDry load before condemning any part. This is the zero-part fix that gets misdiagnosed as a dead heater.
• On the condensation WTG86 a "takes forever / damp finish" complaint that throws E:01 or E:02 is the fluff/lint filter and condenser AIR PATH — owner-clearable maintenance codes, not a heater fault. Bosch's official E01/E02 guidance flags a blocked fluff/lint filter (E01 specifically a blockage in the filter or heat exchanger) and tells you to clean the lint filter and flush fluff from the seals and heat exchanger; a lint-packed manual heat-exchanger chokes the recycled-heat loop so the load never finishes. We rinse the heat-exchanger and clean the filter-sensor area rather than condemn a board. An E:01/E:02 that clears on a heat-exchanger rinse is a no-part repair.
• E:03 on the WTG86 is the condensation DRAINAGE fault, and it reads as "won't dry" because a machine that can't dump its condensate stalls before the load finishes — a full condensate tank, or a kinked/blocked water-outlet hose, or a tired condensate/drain pump 00145623 (genuine OEM, web-confirmed). Bosch's troubleshooting puts zero-part checks first: the outlet hose not connected correctly, kinked or trapped; the hose blocked (rinse with tap water); the condensation-container filter soiled. We clear and test the drain path before quoting the 00145623 pump, because an E:03 that clears on a rinsed hose or an emptied tank is a no-part fix. The 00145623 is shared with Thermador/Gaggenau BSH siblings, so a confirmed number cross-references cleanly.
• Short cycles or a persistently low/damp finish with the air path and sensor both clean points at NTC temperature-sensor DRIFT. The NTC thermistor is the 00613753 (PartSelect PS8727701; genuine OEM — web-confirmed on RepairClinic, AppliancePartsPros and applias as the BSH dryer temperature-regulator NTC sensor). It senses the air temperature the control uses to time and end the cycle; once it drifts, the board reads the air hotter than it is and cuts the heat / ends the program early, leaving clothes damp. We ohm the 00613753 across a temperature swing — on a healthy NTC the resistance must climb as it cools — before condemning it. It's a BSH part shared with Thermador/Gaggenau dryers, so the number cross-references cleanly across the catalogue.
• Don't mis-order the belt as a "won't dry" fix. On the WTG86 platform the BLOWER belt 00604866 (turns the blower WHEEL, not the drum) stalling the recycled-heat loop is a real airflow culprit — the drum still tumbles, but airflow collapses and the load never dries, which owners report as "not drying right." It is frequently confused with the drum-drive belt, which is a separate number that must be pulled by exact model/serial. We confirm which belt by serial before ordering, because swapping a drum-drive belt won't restore airflow a stalled blower belt killed.
• Heat-pump WTW87 (500 Series: WTW87NH1UC) and WQB245 (800 Series: WQB245AXUC) "barely warm / takes forever" is most often NORMAL operation plus a lint-loaded filter — not a fault at all. Heat-pump drying runs at a deliberately lower, gentler temperature (cheaper to run), so a long damp-feeling cycle on these is by design; the recoverable causes are the fluff filters and the condensate path, since the condenser self-cleans. Only a genuine F:06 (heating-circuit / over-temperature fault in the SEALED refrigerant loop, E09 on some firmware) is real heater work, and that is EPA-608 sealed-system diagnosis — compressor, evaporator/condenser airflow, refrigerant charge — not a parts swap. We show owners the maintenance points once and reset expectations before chasing a heater that, on these machines, does not exist.

Bosch not drying (clothes still damp) in Toronto — the local specifics

• The recurring Toronto pattern on Bosch not-drying calls is that the machine is mechanically healthy and the fault is maintenance the owner was never shown: a limescale-filmed moisture sensor ending AutoDry cycles early, a lint-packed manual heat-exchanger on the WTG86 choking the recycled-heat loop, or a condensate tank/hose nobody touched throwing E:03. Heat-pump WTW87 (500 Series) and WQB245 (800 Series) "takes forever" calls frequently turn out to be normal slow heat-pump drying plus a loaded fluff filter — not a fault. We see the same three or four causes repeat across the brand here, sensor-and-airflow far more than dead-heater.
• We bring to these calls the moisture-sensor cleaning kit (white vinegar + non-abrasive pad), the 00604866 blower belt, the 00613753 NTC thermistor, and the 00145623 condensate/drain pump — the parts that close the bulk of Bosch not-drying jobs on the first visit. For confirmed sealed heat-pump (F:06) faults on the WTW87/WQB245 we quote and order per serial rather than carry, and we say so up front.

For the full Bosch dryer module — every fault, part number and code — see Bosch dryer repair in Toronto, and for the same fault across all brands the dryer not drying (clothes still damp) guide.