Bosch 24-Inch Dryers: How a Clogged Condensate Pump Disrupts Drying

How a condensate blockage interrupts drying

Bosch WTB and WTG condenser dryers turn moisture from the laundry into liquid water. A pump moves that water out of the lower collection area through the drain hose. When drainage is interrupted, the machine can stop with the clothes warm and unfinished.

• A restricted or incorrectly connected drain: a kink or blockage prevents free discharge; an unsuitable outlet can allow water to return. A problem beginning after the dryer was moved makes the installed hose and connection especially relevant; inspect only the portion already within safe reach.
• Debris in the lower collection area or pump passage: an internal obstruction can interfere with water movement even after the lint filter and removable heat exchanger have been cleaned. That area requires service access.
• Pump operation or water-level recognition: water removal may stop because pump output is faulty, or the dryer may continue responding as though water remains. A persistent warning after the listed owner checks needs internal assessment before selecting an assembly.

Check drain and DR: use the warning for the exact model

The WTB86200UC manual uses Check drain. The WTG86401UC manual and WTG865H3UC manual use DR. Their troubleshooting guidance describes incomplete drainage, directs the owner to check the hose and connection, and calls for service if the indication persists after that maintenance.

A drainage indication identifies the system to investigate; it is not an instruction to order a pump. The warning-specific guide is Bosch dryer DR problem. If the dryer completes its cycle without a drain warning but leaves laundry damp, load, heat exchange, airflow and laundry-moisture sensing also need consideration.

Why filter cleaning may leave the lower obstruction untouched

The lint filter and removable heat exchanger collect debris in different places from the lower water-collection area. Owner maintenance can restore their airflow without reaching an obstructed internal water passage. During service, lint and residue in that passage must be distinguished from a defective pump.

The dryer also has two different sensing jobs. The moisture bars near the drum opening contact the laundry and help determine dryness. Bosch identifies condensate pump assembly 00145623 as including an electrode. Cleaning the laundry bars therefore does not clean or test the pump assembly's electrode or its connections.

If the warning persists when the lower area has actually drained, electrode contamination, connections and the control's level response become specific inspection targets. Residue alone cannot establish which of those has failed; the relevant comparison is the response with water present and after the water has been removed.

The US models cataloged for pump 00145623

On October 18, 2026, Bosch's US replacement-parts listings showed 00145623 at diagram position 0512 for these 23 complete E-Nr model numbers:

• WTB86200UC: /02, /06, /07
• WTB86201UC: /01, /02
• WTB86202UC: /02
• WTG86400UC: /01, /02, /07, /08
• WTG86401UC: /01, /07, /08
• WTG86402UC: /01, /02, /07, /08
• WTG86403UC: /01, /13
• WTG865H2UC: /01, /02
• WTG865H3UC: /02
• WTG865H4UC: /01

Use the full E-Nr, including the slash and final two digits, in Bosch's model-specific parts catalog before ordering. The list records catalog fit, not the condition of a particular machine or guaranteed future availability.

The 24-inch size and a 300, 500 or 800 Series badge do not extend that fit to other dryers. WTW87NH1UC is a heat-pump model, and newer WQB models have their own water handling and care instructions. Do not transfer this pump number or a WTB/WTG removable-exchanger procedure to them.

What you can check without opening the dryer

• Drain hose and outlet: with the dryer off, inspect only an already accessible section for a kink or pinch. The WTB86200UC and WTG86401UC manuals require free discharge, an unsealed and ventilated drain opening, and a hose end clear of pumped-out or standing water to prevent backflow. Compare the visible arrangement with the exact model's installation drawing. Have a qualified installer correct a mismatch before further drying; leave hidden connections and a stacked or enclosed dryer's movement to qualified service.
• Listed owner maintenance: let the dryer cool and follow the manual's power-isolation and cleaning directions for the lint filter and only the heat-exchanger parts it exposes for owner care. Refit every part correctly.
• Cycle result: distinguish a drainage-warning interruption from a completed but damp load. If a warning returns after the permitted checks, stop restarting loads to clear it.

Do not disconnect the internal pump hose, push tools into hidden passages, pour chemical drain cleaner into the dryer or bypass a sensor. Stop use for leakage, burning smell or a breaker trip; keep clear of water near electrical equipment.

Cleaning or replacement: what separates the repairs

A useful assessment establishes whether condensate reaches the lower collection area, whether the pump delivers it through the installed drain without backflow, and whether the electrode/level response agrees with the water remaining. It also checks the pump's connections and command when movement is absent. This separates restricted water movement from a pump, sensing or control fault.

Cleaning is appropriate when an obstruction is found and removing it restores water removal and the correct level response. Replacement follows a confirmed component fault that remains after restrictions and the installed drainage connection have been addressed. Pump noise establishes neither discharge volume nor a correct level response.

After repair and full reassembly, verification needs the original load/program conditions as appropriate: water must discharge, the cycle must finish, the warning must stay cleared and the laundry must reach the expected result. A brief start is not the same check as completing the drying complaint.