Theory Of Operation; Touch Control Circuit; Element Limiter; Fault Code Diagnosis - KitchenAid KECC508MBL Technical Education

TOUCH CONTROL CIRCUIT

Refer to the strip circuit below.
Whenever a cooktop glass "touch panel" is
touched, an electrical signal is sent to the Elec-
tronic Control (LEO) Board through a connec-
tion cable. The electrical signal closes the ap-
propriate relay on the control, and applies 240
volts to the heating element from the L1 side
of the AC line. Current travels from the ele-
ment to the limiter, which monitors the tem-
perature of the cooktop glass. The circuit is
completed from the limiter to the L2 side of the
line.

ELEMENT LIMITER

Refer to the strip circuit below.
Limiters on standard cooktops utilize two
switches to control two different safety features.
One switch monitors the maximum heat pro-
duced by the burner, and protects the cooktop
glass from overheating. The other switch moni-
tors the burner operation, and uses a hot sur-
face indicator light to indicate when the cooktop
surface is hot and unsafe to touch.
The element limiter on the Tap Touch Cooktop
is different from standard cooktop limiters, be-
cause only one limiter switch is required. This
switch monitors the maximum heat produced
L1
BOARD CONNECTION CABLE
USER
INTERFACE
BOARD

THEORY OF OPERATION

Electronic Control
(LEO) Board
JP19
RL06
RELAY
JP08
by the burner, and protects the cooktop glass
from overheating. The hot surface indicator
light is controlled by a programmed sequence
stored in the microcomputer board. The indi-
cator lights will be activated, based on the
amount of time the burner is on. The hot sur-
face indicator light remains on during the en-
tire operation of the burner, and during the cool-
down period of the cooktop glass. The indica-
tor light "on time" will last beyond the time that
the burner is turned off. As the burner is turned
off, the microcomputer calculates the time that
the cooktop will take to cool down, and keeps
the light glowing during that time. If there is a
power outage during this "calculation time," the
microcomputer will retain the calculated time.
When power is re-applied, the countdown time
will continue, and the indicator light(s) will re-
main on until the countdown is completed.

FAULT CODE DIAGNOSIS

The Electronic Control constantly checks the
operation of the cooktop circuitry. If a problem
occurs, a "fault code" will be generated at the
two front burner controls. The fault code is a
combination of glowing LEDs that indicate a
specific "fault code" number (see page 6-1 for
a description of the Fault Code LEDs).
1200 W 47Ω
YEL/WHT
JP14
ELEMENT
3-1
2A
1A
YEL
LIMITER
L2