Cleveland SteamCraft V, Service Manual

Page: 71 / 96

CET-16 Service Manual Page 69
6. Slowly turn potentiometer counter clockwise until contactor
just turns off. The contactor should begin to cycle on and off.
7. Continue to adjust potentiometer until the off time period in
these cycles is 4 to 6 seconds. Since the on/off cycle time win
be affected by water fill solenoid operation, it is best to check
timing at a time midway between water fin cycles.
NOTE
When the DRAIN TEMP ADJUST potentiometer is
set property, the drain water temperature will
average 150°to 160°F. Measure this temperature with
a thermometer in the water flow at the open discharge
from the steamer.
Resistance of a negative temperature coefficient thermistor
decreases as temperature increases. To test a thermistor,
connect an ohmmeter to the thermistor leads and observe the
changes in resistance as the thermistor is heated. To determine
proper operation of a thermistor left in the circuit, observe the
following,
1. Turn off the steamer and allow to cool.
2. Disconnect the thermistor and connect an ohmmeter to the
thermistor leads. Leave meter connected throughout test.
3. Measure the resistance of the thermistor at room temperature;
it should be between 90,000 and 125,000 ohms.
4. Turn on the SteamCraft V and observe the decrease in
resistance of the thermistor as the unit heats. After 10
minutes, the resistance should decrease to between 10,000
and 25,000 ohms.
5. Disconnect the ohmmeter and reconnect the thermistor.
Printed 4/90
Thermistor Testing