Bosch WTV74308GB/11 Tumble Dryer Filter/Venting Hose Fault Light

December 19, 2024

Customer Question

Joe Williams asks:

Bosch WTV74308GB/11 Tumble Dryer will stop after 20-30 minutes with a flashing "Filter/Venting Hose" error light. Video here: https://youtu.be/JxbCHYoHDRMPlug-in power meter shows that it's drawing the expected amount of power at full heat. There is a single timed program, but this never uses the full heater power so doesn't normally trigger the fault.I have checked:- filter is clean.- path from filter to vent hose is clean; there's a removable maintenance panel on the side which makes this very easy!- vent hose and external vent are both brand new and completely clean.- thermostats around heater both closed circuit at cold.- resistance of heater coils is as expected (2 heater coils appear to be used independently or together to provide 3 heat levels.)- NTC sensor on the heater shows ~30k ohms when cold, reduces when warmed.I am wondering how it senses a blockage in the filter/hose area - could there be another NTC sensor in the exit vent giving readings lower or higher than expected? I can see that there are 3 pairs of wires going from the control board down the left-hand side of the machine - 1 pair definitely goes to the door sensor and another appears to lead to the internal moisture sensor.

Model: WTV74308GB/11

Paul Says:

I will try and help with this problem about Bosch WTV74308GB/11 Tumble Dryer,

Good morning Joe,

I'm sorry to hear about the trouble with your Bosch vented tumble dryer, model number Bosch WTV74308GB/11. Thanks for providing the full model number; it helps me get the right diagrams for you. I also appreciate the quick video showing the vent light coming on.

From what I've seen, there aren't many sensors on this dryer. It has a normal thermostatic system on the heater, a moisture sensor, and one additional thermostat. Here are some steps to check:

1. Inspect all the ducting system throughout the machine. Remove the back panel and ensure everything is clear from the motor to the heater.
2. Check the motor fan blade system since it supplies airflow through the machine. If the blade is broken or loose, it won't create enough air pressure.
3. Look at where the filter sits at the front of the machine. Remove it and inspect down the hole at the bottom, as this connects to the ducting tube system running to the back.
4. Examine how you have fitted the waste hose, whether through a wall or window. Ensure there are no kinks in the pipe, and try running the machine without the vent hose connected.

You mentioned that on a timed program, it uses less energy on heat, suggesting an overheating issue due to poor circulation. This points to an airflow problem because when using sensor programs, it triggers a fault, but not on a timed system.

Check all ducting units and motor fan blades, and test without the vent tube. Ensure moisture sensors inside the drum are clean; usually, dirty sensors trigger a different fault type.

It could be a faulty thermostat reading incorrect temperatures or an airflow issue. Without having your machine here, it's hard to diagnose precisely. Unfortunately, I don't have a workshop manual for this model as Bosch keeps their technical information for their engineers only.

Good luck with your repair. If you need more help, feel free to contact us.

Best regards,

Thanks a lot for sending your video about the problem:

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Bosch WTV74308GB/11 Tumble Dryer Spares

Bosch WTV74308GB/11 Tumble Dryer Control Panel

Bosch WTV74308GB/11 Tumble Dryer Cabinet

Bosch WTV74308GB/11 Tumble Dryer Door

Bosch WTV74308GB/11 Tumble Dryer Drum

Bosch WTV74308GB/11 Tumble Dryer Other Parts

Reference	Part Number	Description
0101	00640671	Cover
0102	00600616	Knob-programme
0103	00600148	Spacer
0104	00651052	Control module
0105	00623688	Capacitor-interference
0106	00644995	Power cord
0107	00674258	Panel-facia

Reference	Part Number	Description
0201	00247370	Panel side
0202	00244037	Panel side
0203	00475311	Front panel
0204	00475305	Hood
0206	00649012	Heating element
0207	00600157	Sensor-NTC
0208	00617459	Limiter-temperature
0209	00248251	Case-rear part
0210	00670752	Exhaust air hose
0211	00619745	Lamp
0212	00445048	Duct
0213	00445049	Duct
0214	00622324	Lock-mechanical
0218	00611613	Clip
0219	00249288	Bearing shield
0220	00613751	Cover
0221	00600155	Sealing
0223	00652184	Fluff Filter for Tumble Dryers
0224	00154159	Holder
0225	00420271	Clamping piece
0226	00600811	Holder
0227	00600433	Cover
0228	00656841	Sealing
0230	00770163	Worktop
0231	00613598	Wheel
0232	00600080	Light socket
0233	00605426	Lid
0237	00700248	Front rail

Reference	Part Number	Description
0301	00644221	Replacement handle for tumble dryers
0302	00445736	Frame
0303	00614390	Hook
0304	00445735	Window
0305	00646933	Door hinge

Reference	Part Number	Description
0401	00497211	Drive coupling
0402	00657917	Belt-drive
0403	00618931	Bearing
0404	00652500	Seal set - drum support
0405	00649045	Sealing
0407	00249014	Drum
0410	00652502	Taper

Reference	Part Number	Description
0501	00611942	Foot
0502	00145467	Motor
0503	00615653	Spring
0504	00600436	Roller-tension
0505	00600151	Belt-drive
0507	00647543	Fan drum
0508	00610150	Capacitor-metal paper
0509	00660913	Air channel exhaust
0512	00605425	Stud
0519	00445593	Cover
0520	00660918	Cover
0526	00751938	Lid
0532	00770028	Case-bottom