Models 24-CGA-10 and 24-CEA-10
SteamCraft 10 Service Manual, Chapter 5
Page 79
Gas Burner Ignition and Combustion Functions
Model 24-CGA-10
Gas-fired SteamCraft 10's have a blower powered, two stage combustion
system with an intermittent pilot igniter coupled to an automatic gas valve
and control module. This system initiates and controls gas flow, ignition,
and combustion. The burners heat the water in the steam generator through
the heat exchanger. The blower forces the combustion gasses up the heat
exchanger tubes which run through the entire height of the steam generator.
The control module regulates igniter and gas valve operation.
A. During preheat and steaming cycles, the combustion system is energized
through combined action of the Lower Float Switch (L.W.C.O.) and
various other components. The normally open lower float switch closes
only when generator water level covers the heat exchanger tubes.
• During Preheat; The L.W.C.O. Switch energizes the combustion
system components through the normally closed Preheat Switch
(Figure 5-3). This switch opens and closes to control the preheating
as described on page 74.
• During Steaming: The L.W.C.O. Switch energizes the combustion
system components through the normally open R1 and/or R2 relay
contactors. These contactors remain closed as long as their respective
compartment control panels are set for steaming. Operation of these
relays is described on page 77.
B.
Refer to Figure 5-10. When the combustion circuits are energized, the
ignition and combustion sequence starts.
1. The energized relay R3 closes its R3 contactors, starting the combus
tion fan motor.
2. When the combustion fan reaches operating speed, the air prover
switch senses air flow and closes, energizing the control module.
3. The energized control module counts down a 45 second delay and
starts burner ignition. The module simultaneously sparks the pilot
igniter and sends gas to the pilot.
4. When the igniter sensor detects pilot ignition, the control module
opens gas flow to the burners.
5. If the pilot flame sensor does not detect pilot ignition within 90
seconds, the control module stops both pilot spark and gas flow.
C
. The two stage gas valve enables operation at two different burner
capacities.
• When both cooking compartments are steaming, the burners operate
at 100% capacity (125,000 BTU/hr).
• When only one cooking compartment is Steaming, the burners
operate at 60% capacity (75,000 BTU/hr).
Burner Ignition and Control System
The SteamCraft 10's Intermittent Pilot (IP) Ignition and Control System is
comprised of White Rogers and Honeywell components. The associated
White Rogers and Honeywell manuals are duplicated in Chapter 8. All
troubleshooting, maintenance and repair of the IP Burner Control System
Components should be done according to these manuals.
Cleveland Range, Inc.
Printed 3/93
Figure 5-10. Partial Schematic
Burner Ignition - 24-CGA-10
