Troubleshooting - Bosch DAH94 Use And Care Manual

Before calling service, check the possible explanations below. If these solutions fail, call Bosch service at 800-944-2904.
Please have your serial number and model number ready. They are located on the underside of the hood on the left side.
Problem
Noise during operation.
Noise when not operating.
Fan motor does not work.
Filter light does not turn off (DAH95 models only).
Filter light does not turn on (DAH95 models only).
Filter light comes on. (DAH95 models only).
Lights under hood hum.
Operation of hood trips breaker.
One light above Speed button blinks (DAH95 models only).
All three lights above Speed button blink (DAH95 models only).

Troubleshooting

Some noise is normal due to vibration and air movement.
Excessive noise indicates one of the following:
Ductwork is too small/ undersized.
•
Ductwork is too big/ oversized.
•
Ductwork is loose.
•
Transtition is too small/ too loose.
•
Togglebolts are not tightened.
•
Loose screws in trim parts, ect.
•
Backflow flap on outside of duct wall cap moves with the
wind.
Power supply to hood is not sufficient.
Wires are not completely connected.
Light must be reset: hold filter button down for 3 seconds
(Always clean filters before resetting filter light).
Filter light will not come on until after 40 hours of operation.
Indicates that filters should be cleaned. Hold button down
for 3 seconds to reset.
A slight hum is normal.
Wiring is not correct.
•
Circuit is not correct.
•
Conditions exceed allowable temperatures. Turn on next
speed level.
Heat sensor is not working. Call service.
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Possible Explanations