Door Interlock Switch; Steam Solenoid Valves; Indicator Lights; Cooking Compartment Thermostatic Switch - Market Forge Industries ST-10 Owner's Manual

SECTION 5. TROUBLE-SHOOTING
1. Carefully check motor wire leads and tighten
loose connections.
WARNING:
Use care while working with control panel.
Terminals carry 120 volts.
2. Turn on power to the cooker.
3. Set timer dial (any setting beyond "0-Min-
ute"). If operation is correct, the motor will
turn the dial toward "0-Minute." If the motor
fails to operate, it is defective and the entire
timer must be replaced.
4. Shut off power to the cooker.

5.4.5 DOOR INTERLOCK SWITCH

Malfunction of the cooker door interlock switch
prevents timer indicator lights from turning on and
steam solenoid from opening when the timer dial
is set. If steam does not enter the compartment
and the indicator light fails to turn on with the door
latch securely engaged, the fault may be in the
door interlock switch.
Proceed as follows:
1. Turn off power to the cooker.
2. Disconnect wires to the door switch termi-
nals (see Figure 5-1).
3. Connect an ohmmeter between the termi-
nals of the switch.
4. Actuate the switch by closing the cooking
compartment door. If a zero reading can-
not be obtained, the switch is defective and
must be replaced.
5. Remove the ohmmeter and replace the
leads on switch terminals (see Figure 5-1).

5.4.6 STEAM SOLENOID VALVES

When either inlet solenoid valve fails to operate,
the fault may be a defective coil. A defective coil is
found using an AC volt-meter to check the voltage
at the coil wire terminals, with the cooker compart-
ment operating in either CONSTANT STEAM or
60-MINUTE TIMER mode. If voltage of 120 volts
is present and the coil fails to open the valves, the
fault is in the valve coil. Defective valve coils are
not separately replaceable, requiring complete
valve replacement.

5.4.7 INDICATOR LIGHTS

If the cooker compartment functions correctly, with
the single exception that the indicator light fails to
light during operation, the fault is a defective indi-
cator light. A "burned out" or defective light is veri-
fied by using an AC volt-meter at the leads, with
input power on the selector switch in the correct
position for that timer, the timer set, and the door
latches closed. If 120 volts is present, the fault is
in the indicator light and requires replacement. If
120 volts is not present, the fault is in the wiring
or control components (selector switch, timer, or
door switch).
5.4.8 COOKING COMPARTMENT
THERMOSTATIC SWITCH
A thermostatic switch included in the circuit for
the timer motor delays timer operation until steam
flowing into the compartment satisfies the temper-
ature-actuated switch device. If a timer motor fails
to operate within about one minute after the in-
dicator light comes on (with cooker compartment
empty), the cause may be a defective thermostatic
switch. To test the switch, proceed as follows:
1. Disconnect the two wires connected to the
thermostatic switch terminals.
2. Connect an ohmmeter between the two ter-
minals of the switch.
3. Place the cooker into operation and observe
ohmmeter dial. Within one minute of opera-
tion, the switch contacts close automatically
to register a zero ohm reading on the dial.
If a zero ohm reading is not obtained, the
switch is defective.
4. Shut off cooker, disconnect ohmmeter leads,
and replace wires on switch terminals.

5.4.9 BUZZER

If the buzzer does not sound at the termination
of the operator-selected timer setting (timer dial
returned to "0-Minute" position), the fault may be a
defective buzzer. Buzzer operation is verified us-
ing an AC volt-meter at buzzer coil connections
with input power on and selector switch and co-
inciding timer dial set at the "0-Minute" position. If
voltage is 120 volts, the fault is in the buzzer,
which must be replaced. If 120 volts is not pres-
ent, the fault is in the wiring or control components
(timer or selector switch).
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