CleaverBrooks CBEX Elite Operation And Maintenance page 18

5
Main Gas Train
FIGURE 2-3.
Component
1. Pilot Gas Shutoff Cock
2. Pilot Gas Pressure Regulator
3. Pilot Gas Pressure Gauge
4. Pilot Gas Valve
5. Gas Shutoff Cock
6. Low Gas Pressure Switch
7. Main Gas Valves
8. Gas Valve Actuator w/o POC
9. Leakage Connection
10. Gas Regulating Actuator w/
POC
2-4
10
8
6
9
7
For manually opening or closing the pilot gas supply.
Reduces incoming gas pressure to suit the pilot.
Indicates gas pressure to pilot.
A solenoid valve that opens during the ignition period to admit fuel to the pilot. It
closes after main flame is established. The sequence of energizing and de-energiz-
ing is controlled by the programming relay. A second gas pilot valve may be
required by insurance regulations.
The upstream gas cock manually opens and closes the main fuel gas supply. A
second shutoff cock, downstream of the main gas valve(s), is installed to provide
a means of shutting off the gas line whenever a test is made for leakage across the
main gas valve.
A pressure actuated switch that is closed whenever main gas line pressure is
above a preselected pressure. Should the pressure drop below the setting, the
switch contacts open a circuit causing the main gas valve(s) to close, or prevent
the burner from starting. The switch is usually equipped with a device that must
be manually reset after being tripped.
Electrically actuated shutoff valves that open simultaneously to admit gas to the
burner. The downstream valve is equipped with a "proof of closure" switch that is
connected into the pre-ignition interlock circuit.
Dual-body gas valve includes regulating valve with POC (see below) and second
motorized safety shutoff valve.
The body of the gas valve has a plugged opening that is used whenever it is nec-
essary to conduct a test for possible leakage across the closed valve.
Regulates gas pressure to the pressure range required by the burner. Includes
proof-of-closure switch.
11
9
5
Description
Burner and Fuel System
750-368
CBEX Elite 100-1200 HP