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Page 58
CET-16 Service Manual
Heater Element Testing
120 VAC CIRCUITS
Power Circuits
DEATH, INJURY, OR EQUIPMENT DAMAGE may be
caused by the voltages associated with the generator
and heater elements.
Turn the power OFF at the external disconnect switch
before testing the heater elements.
The steam generator and fan heater elements may be tested while
installed the steam generator with or without wiring connected. When
testing a heater element, observe the following considerations.
1. Before performing tests that require steamer disassembly, observe the
heater elements during steamer operation. The formation of small
steam bubbles around an energized heater element indicates the
element is operating correctly. Note that the heaters operate only when
the door is dosed. To simulate a dosed door, refer to the Door Sensor
section, page 62.
2. Turn power off at external disconnect switch.
3. Measure the resistance between the heater terminals and the steam
generator tank (ground). The heater element is undamaged if a very
high (over 1 megohm) or infinite resistance is measured between
either terminal and ground.
4. Measure the resistance of the beater element and compare the results
to the values in Tables 5-1 and 5-2 for the particular part number
being tested.
5. When testing an element known to be good, it is possible to identify
the part number by matching the actual measurements with the
ratings listed for each part number.
The l20 VAC circuit draws power from the 120 VAC secondary windings
of the transformer. This circuit includes the contactors and solenoids
which control the heater elements, can motor, water fill valve, and
condenser spray valve. The board-mounted relays K1,K2,K3, and K4
control 120 VAC power to the front contactors, rear contactors, and
fill/condenser solenoids through the six pin plug CON 3.
When troubleshooting or tracing circuits, refer to the block diagram (Figure
5-1), and Table 6-1 for the wiring and schematic diagrams that apply to the
unit being serviced.
For ease of identification, all 120 VAC circuits are wired with 18 AWG wire,
white or white with color tracer (stripe). One harness assembly contains all
120 VAC wiring and connects to the control board through CON 3. The
acceptable voltage range for the 120 VAC circuits is 105 to 140 VAC as
measured at the transformer with the loads disconnected.
WARNING
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Table of Contents
Troubleshooting
