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New Liquid Fuel check valves were changed in combustion inspection, but when starting the unit with distillate fail to ignite several time. LF pump pressure is 8.7 bar at 440 rpm when the firing, small amount of smoke coming from stack and no liquid fuel coming from false start drain. We checked all things causing fail to ignite, but no fire. We test the vck opening pressure, it open at 7.8 bar.
After that we fired the unit with natural gas and did transfer from gas to distillate at full speed no load. the transfer succeeded. the LF pump pressure was 15 bar during transfer so the check valves opened. Then we stopped the unit and restarted with liquid fuel.The unit fired normally.
Why the check valves not opened From the beginning? what if we haven't natural gas?
After that we fired the unit with natural gas and did transfer from gas to distillate at full speed no load. the transfer succeeded. the LF pump pressure was 15 bar during transfer so the check valves opened. Then we stopped the unit and restarted with liquid fuel.The unit fired normally.
Why the check valves not opened From the beginning? what if we haven't natural gas?