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Tim Cooke
Tim Cooke,
Category: Appliance
Satisfied Customers: 1174
Experience:  Owner at Self-employed
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I have a Bosch HLN658250B/01 oven. The circulation fan stays

Customer Question

I have a Bosch HLN658250B/01 oven. The circulation fan stays on long after the oven has cooled. I'm happy to do a repair myself if practical if you can identify the faulty part please.
JA: Is your Bosch oven gas or electric? How old is it?
Customer: All electric. About 10 years. Everthing else working fine.
JA: How long has this been going on with your Bosch oven? What have you tried so far?
Customer: Fault started after lunch today. Have only tried depowering and turning on again - fan starts up straightaway.
JA: Anything else we should know to help you best?
Customer: I have seen similar fault with this Bosch model reported on online forum - is it easy to diagnose based on what I've told you? I'm happy to tackle replacing a part if possible.
Submitted: 7 months ago.
Category: Appliance
Expert:  Tim Cooke replied 7 months ago.

The fan control relay has stuck or fused in the on position.

The relay is on the control board. You might persuade it to unstick by tapping its casing, but if its fused then you'll have to replace either the relay or the complete board.

Or, you can just turn off the supply to the oven when it has cooled down.

Customer: replied 7 months ago.
Anything I need to know before opening up? - obviously I will disconnect first.
Is fan control relay obvious? Are you able to find me the replacement part number please?
Expert:  Tim Cooke replied 7 months ago.

I wrongly assumed, without asking, that the oven element switches off when the oven reaches the set temperature. If not, then the temperature control thermostat is faulty. It's also worth checking the high-limit thermostat as that can cause the fan to remain running.

Replacing a relay would be a board-level repair, if you have the skills and tools to to do that. Otherwise it would be a new control board. If it comes to that I can find you the part number.

Customer: replied 7 months ago.
there is no sign that the oven element didn't turn itself off as it should have done when it reached the set temperature.
We have just been using the hob and one of the rings cannot be used and shows code c3. Also the hob turned itself off once but we were able to switch it on again. Presumably these faults are connected and is it something that would be cured by a new control board?
Expert:  Tim Cooke replied 7 months ago.

Well, I can't find a definition of "c3", but I believe the hob control board is a different part to the oven control board.

When you wrote "there is no sign that the oven element didn't turn itself off", did you really mean "didn't" as that's a double negative?

Customer: replied 7 months ago.
What I meant was that the oven behaved normally and did not overheat. The initial symptom was merely that the circulation fan kept running for several hours after the cooker had been turned off. The cooker has now apparently developed other faults connected with the hob - one of the rings cannot be used. It immediately shows c3, which according to my manual means the hotplate has overheated and has switched itself off.
Expert:  Tim Cooke replied 7 months ago.

OK. I understood the hob symptoms, but I would expect that to have its own control board - I think the hob and the oven are unconnected except that their share the power board.