Cleveland SteamCraft 10 Service Manual page 108

Page 102 SteamCraft 10 Service Manual, Chapter 6
YES (Continued)
Start a stopwatch when the lower magnetic float closes the lower proximity switch.
IT:2-3 Does the burner fan motor start when water reaches the safe operating level.
Printed 3/93
3. If the plumbing, drain and fill valves are not blocked, test the operational water
float for continuity through the upper switch according to component test CT:6.
NOTE: This switch controls operation of the fill solenoid valve during preheat
and steaming operations. It is normally closed, and remains closed until float
water level reaches approximately one inch from the top of the float cylinder.
4. If the operational water float is functioning property, test the water fill solenoid
valve according to component test CT:4.
5. If the water fill solenoid valve is functioning properly, test the 3-way drain valve
according to component test CT:1.
NOTE: This valve is normally open, directing water flow to the drain piping.
During preheat and steaming operations, the solenoid closes this valve directing
water to the steam generator. The valve remains closed until the float water level
reaches approximately one inch from the top of the float cylinder.
NOTE: During preheat and steaming operations this lower float switch controls
operation of the burner components through the Preheat Thermostat and relay R3.
This switch is normally open, and remains open until the float water level is
approximately one inch from the bottom of the float cylinder.
Use the stopwatch to measure elapsed time between dosing of the lower float switch
and burner ignition. This should be approximately 90 seconds but no less than 45
seconds.
NOTE: The lower float switch closes when water reaches safe operating level. The
burner fan should start when the switch closes. Starting the burner fan motor is the
first step in the burner ignition sequence. If the fan does not trigger the air prover
pressure switch, the burners do not light.
Failure of any of five components can prevent the burner fan from starting the burner
ignition sequence in preheat mode.
1. Check the lower float switch according to component test CT:6.
2. Check the transformer that powers the gas burner control circuit. Is the voltage at
the secondary terminals 24VAC (nominal)?
• If the voltage is present, proceed to step three.
• If the voltage is not present, test the transformer according to component test
CT:7.
3. Check, the preheat thermostat according to component test CT:8.
4. Check the relay R3 according to the relay testing instructions in Component
Testing Fundamentals.
Models 24-CGA-10 and 24-CEA-10
Cleveland Range, Inc.