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The electrical trouble-shooting procedures that follow
require access to components and terminals of the
electrical control panel shown in Figure 7-3. Electrical
controls are reached by removing screws that fasten the
control panel to the frame. The panel may be pulled
forward for testing while interconnected to the cooker
circuits or disconnected at the pin connection for complete
removal and repair.
5.4.1 Incoming Power
Before trouble-shooting any of the electrical parts or
assemblies, verify that power is being supplied to the
cooker. Incoming power is connected at the boiler (or
direct-connected steam) control box located in the base
cabinet. With power connected to the cooker, an AC volt-
meter is used to measure 120 volts across L1 and L2. If
120 volts is present, and the cooker will not operate, the
fault lies within the electrical circuits of the cooker.
5.4.2 Electrical Inspection
The first step in any electrical trouble-shooting procedure
is a thorough physical inspection of all wiring connections.
To access electrical components, remove the control panel
as explained in Subsection 6.3.4.
Warning
Before removing control panel or checking connections
and wiring, be sure that the circuit breaker for incoming
power is OFF. When power is supplied, all exposed
terminals of the control panel carry 120 volts.
Check all wiring connections by hand to assure that both
ends of all connection points are tightly secured. Use a
screwdriver to tighten connection points. If necessary,
visually inspect all quick-disconnect terminals for evidence
of corrosion. Terminals in this condition should be
separated, cleaned with emery cloth until shiny, and tightly
reconnected.
5.4.3 60-Minute Timer
5.4.3.1 Timer Contacts
Defective timer contacts will result in failure of either
cooker compartment to operate. When this occurs, remove
the control panel (see Subsection 6.3.4), and proceed as
follows:
1. Turn off power to the cooker at external circuit breaker.
2. Disconnect all five wires from timer terminals
(see Figure 5-1
).
3. Connect an ohmmeter between terminals 1 and 3.
4. Rotate timer dial beyond the "0-Minute" point (any
setting) to obtain a reading of zero ohms on the
ohmmeter. If zero ohm reading cannot be obtained,
SECTION 5 TROUBLE-SHOOTING
timer contacts are defective and the timer must be
replaced.
5. Move ohmmeter leads to terminals 1 and 4.
6. Rotate timer dial to "0-Minute" position (an audible click
indicates correct position). If zero ohm reading cannot
be obtained, the timer is defective and must be
replaced.
7. Remove ohmmeter and replace all five leads on timer
terminals as shown in Figure 5-1.
5.4.3.2 Timer Motor
A defective timer motor will cause continuous operation in
the Time mode, with the timer dial failing to return to the
"0-Minute" position. Since thermostatic switch failure can
cause the same symptom, fault must first be isolated to
the timer by testing the thermostat (see Subsection 5.4.8).
To confirm timer motor condition, proceed as follows:
1. Carefully check motor wire leads and tighten loose
connections.
Use care while working with control panel. Terminals carry
2. Turn on power to the cooker.
3. Set timer dial (any setting beyond "0-minute"). If
operation is correct, the motor fails to operate, it is
defective and the entire timer must be replaced.
4. Shut off power to the cooker.
5.4.4 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 terminals
(see Figure 5-1).
3. Connect an ohmmeter between the terminals of the
switch.
4. Actuate the switch by closing the cooking compartment
door. If a zero reading cannot 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).
5-2
WARNING
120 volts.
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