How It Operates - Electrolux 30" Service Manual

4. Top elements - three types are used; a single
element, a dual element, and a bridge element.
Bridge
Top elements

How it operates:

Whenever the range is connected to electrical power,
low voltage from the mother board is applied across the
two outside pins of the potentiometers.
microprocessor then reads the resistance of the
potentiometers. When the switch knob is depressed
and turned the wipe arm attached to the center pin of
the potentiometer is turned to a resistance range that
the microprocessor can read. The microprocessor then
compares these two readings and displays the setting
in the UIB display window for that element. To prevent
the microprocessor from reading a short or an open, a
fixed resistance is connected to each end of the
adjustable resistor internally. The 10,000 Ohm
potentiometer has a 500 Ohm resistance on each end
of the winding and the 20,000 Ohm potentiometer has a
1,000 Ohm resistance on each end of the winding.
The setting display in the UIB display window will read
from Hi to Lo with numbers in between (see following
chart). The microprocessor operates on a 15 second
duty cycle. When the knob is turned to the HI position
the mother board applies line to line voltage to the
element all the time. In any other setting other than Hi
the microprocessor will cycle line to line voltage to the
element by opening and closing the relay on the mother
board for that element.
NOTE: On glass top ranges the element may cycle in
the Hi position because of the limiter in the
element that protects the glass.
Expandable
Warmer Small
Display % Of
Reading On Time
Lo
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
3.5
NOTE: In the Lo position a 2500 watt element would
be operating at 25 watts.
The
The display is also used as a hot surface indicator on
glass top ranges. The mother board is connected to the
hot surface contacts of the element's limiter. When the
potentiometer is turn to the off position, if the hot surface
contacts of the limiter are closed the display will read
HE for hot element until the element cools down and the
hot surface contacts of the limiter opens.
Troubleshooting the ESEC 5:
The ESEC 5 has some self diagnostics built into the
microprocessor to help in troubleshooting the system.
When a failure occurs one of three codes will appear in
all the display windows: F5, F6, or F7.
F5 code: (Communication break between Mother
board and UIB's)
Indicates a harness, mother board, or user interface
board has failed. The harness is the first thing to check,
unplug the harness, inspect each connection and Ohm
out the harness.
P in 1
M oth er
board
36
Display
Reading On Time
1 4.0
2 4.5
3 5.0
4 5.5
5 6.0
6 6.5
8 7.0
10 7.5
12 8.0
15 8.5
20 9.0
25 Hi
30
R ig ht-han d
U IB
% Of
35
40
45
50
60
70
75
80
85
90
95
100
Left-h and
U IB