Bosch HBL 73 Service Manual page 33

Tuesday, June 18, 2002
BOSCH 700 SERIES:
ELETTRODOMESTICI
SERVICE INSTRUCTIONS FOR OVEN TESTING AND BASIC TROUBLESHOOTING
VIA CHECCHI 98
I 21013 GALLARATE
ITALY
8. SAFETY THERMOSTATS. The oven is provided with two safety thermostats, mounted together, behind the cooling fan. The
high temperature one (165°C) is always connected in series with the heaters, the low temperature (110°C) is by-passed during
self-clean. They open L2 circuit when temperature gets too high.
9. ROTARY SWITCH. By means of the knob placed on the front panel, the user activates this electronic device. The control
counts the detents and is also able to distinguish if the rotation verse is clockwise or counterclockwise.
10. RTD TEMPERATURE SENSORS. They are mounted inside the cavity (one per cavity), fixed from the outside, on the rear wall.
They are the only means to measure oven temperature.
11. LATCH MECHANISM. A motor is activated to lock the door as soon as self-clean starts. When clean stops, the control wait for
the cavity cooling down below the temperature threshold. The same motor moves to unlock the door.
12. COOLING FAN. It works at two different speeds, in self-clean and ordinary cooking modes. A resistor in series reduces the
voltage on the fan motor and consequently it lowers the fan speed. When the door is locked in self-clean, the resistor is by-
passed by a latch contact, in order to run the fan at full speed.
13. CONVECTION FAN. It works at reduced speed in preheat phase and at full speed at steady conditions. Clean always work at
full speed. A resistor in series with the fan coil reduces the speed, a relay driven by the control by-passes this resistor when
requested.
14. OVEN LIGHTS. Halogen 12V lamps, powered by a 4VA transformer, fused on its secondary winding.
15. MEAT PROBE. The oven is provided with a meat probe, which needs only to be plugged in its own receptacle on the cavity left
side. In the double oven, only the upper cavity is provided with the meat probe.
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