Question about Bosch HBN 455 Stainless Steel Electric Double Oven

2 Answers

Bosch HBN 455 Oven Cooling-Fan Issue

We recently moved to a house that has a Bosch HBN 455 double oven installed. I've noticed that after we have finished cooking (so far only in the top oven), the oven's cooling-fan repeatedly cuts in and out for some time afterwards. I'd expected the fan to stay on, but ours cuts in and out as often as every few seconds, barely getting up to speed before slowing again... and then restarting (sometimes almost immediately, sometimes after a few minutes). Between each change in state I can hear a slightly buzzy electrical click, which I guess is a thermal switch triggering all this. It all sounds kinda odd -- I had assumed that the cooling-fan would simply stay on until the oven had cooled to a certain temperature... and that THEN the thermal switch would trigger (which is how the newer Thermador oven in our old home behaved). Is what we are experiencing normal behavior for this particular Bosch oven? Or is there likely a fault? Many thanks.

Posted by peterhaynes on

  • Anonymous Dec 19, 2007

    I have HBL 455 double oven and have had it for 2 years, but have only used bottom oven maybe four times since installing it. I have a very similar problem to yours. The fans comes on and off and on again and the bottom oven particularly begins hesitating and lagging when it is on, It was also rattling. I have gotten somewhat used to the top oven fan, but the bottom one does not sound right and rattled. I too think it is odd and difficult to accustom to.

    My current problem and a major one is that the lower oven (which I have used maybe 3 or 4 times since I've had it) will not self-clean. The oven door should self-lock after reaching a certain temp. of 525 degrees or so, but mine will not lock and thus the self-clean will not continue to work I had an appliance tech come out for diagnostics, and he saw himself that the self clean was not locking/working. He didn't know what it might be, so he came back and ran it through check points with the help, over the phone from a Bosch corporate tech and the check points came out positive, which should mean everything is fine. He also changed out the control knob and replaced the fan motor iof the bottom oven. He then tested the self clean function, but instead of allowing the oven to self- lock on its own,which is the original problem, he somehow manually locked it and then started the self- cleaning cycle.. I asked him why,he wouldn't just allow the oven to begin the cleaning cycle and then observe to see if the door would automatically lock on its own, as it should when reaching the proper temperature. I don't understand the logic, but he claimed that since he locked the door and the cycle began that it means, the motor is working and thus will also unlock on its own when it cools down. He left and the oven continued cleaning, and then stopped so the fans could cool, and as you said they came on and off and hesitated back and forth sort of lagging. Well now the cycle has finished, the yellow light stayed on, so I finally turn off knobs and now ---I can't open the door.! It is locked and will not unlock.

    I need that oven this weekend, with 4o people coming over and 16 pounds of meant to cook. I'm very frustrated, and confused. Do any of these problems sound familiar.



2 Answers


After the oven is switched off, the after-run of the cooling fan is controlled by an electromechanical thermostat switch. The fan can switch back on, due to residual oven heat that accumulates within the oven's outer case and reactivates the cooling fan temperature switch. Considering yours is making buzzing sounds and activates on and off, the fan's thermal switch may have dirty contacts or just be defective and require replacement.

Posted on Oct 02, 2007



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Our HBN655 had similar issues- the upper cooling fan would cycle on and off on a relatively quick duty cycle until the whole mess cooled off enough and it shut off.
My workaround is to turn the temperature dial off but leave the oven function dial on to BAKE. This seems to force the fan to stay on; then we shut it off a while later and avoid the annoying fan cycling.
(note- 2 years ago, our fan became intermittent, varying speed, etc... for about 2 months before it quit entirely. When that happened, the oven started to heat then the thermal cutout kicked in and the oven shut down entirely. We ended up replacing the fan and that fixed the bug... except now it's starting to act up again...)
(also note- the racks on this beast have a faulty design. if you have a heavy casserole and slide the rack out all the way, it tends push the sidewalls apart and the rack drops. I spoke with Bosch about this and they sent me new racks, no charge... so they know there's a problem. But the new racks don't fix the bug; they just make it harder to reproduce. I have actually had one rack fall with 2 piping hot casseroles on it. Fortunately no one was hurt.)

Posted on Nov 04, 2007


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