CleaverBrooks FLX Operation, Service And Parts Manual page 85

Troubleshooting
Problem
PILOT FLAME, BUT NO
MAIN FLAME
BURNER STAYS IN LOW
FIRE
SHUTDOWN OCCURS
DURING FIRING
750-177
1. Insufficient pilot flame.
2. Gas Fired Unit.
A. Manual gas cock closed.
B. Main gas valve inoperative.
C. Gas pressure regulator inoperative.
3. Oil fired unit.
A. Oil supply cut off by obstruction, closed valve, or loss of suction.
B. Supply pump inoperative.
C. No fuel.
D. Main oil valve inoperative.
E. Check oil nozzle, gun and lines.
4. Flame detector defective, sight tube obstructed or lens dirty.
5. Insufficient or no voltage at main fuel valve circuit terminal.
1. Pressure or temperature above modulating control setting.
2. Manual-automatic switch in wrong position.
3. Inoperative modulating motor.
4. Defective modulating control.
5. Binding or loose linkage, setscrews, etc.
1. Loss or stoppage of fuel supply.
2. Defective fuel valve; loose electrical connection.
3. Flame detector weak or defective.
4. Lens dirty or sight tube obstructed.
5. If the programmer lockout switch has not tripped, check the limit circuit for an
opened safety control.
6. If the programmer lockout switch has tripped:
A. Check fuel lines and valves.
B. Check flame detector.
C. Check for open circuit in running interlock circuit.
D. The flame failure light is energized by ignition failure, main flame failure,
inadequate flame signal, or open control in the running interlock circuit.
Solution
Chapter 6
6-3