Siemens LMV5 Series Technical Instructions page 136

Technical Instructions
Document No. LV5‐1000
NOTE: While commissioning the Ratio Control Curves, it is the responsibility of the technician
to ensure that safe fuel / air ratios are being maintained. If an AZL5 arrow key is held down
when adjusting an actuator position, the position will be changed at a progressively faster
rate.
5. Set the load number to 100%. Increase the effective firing rate of the burner by increasing the
actuator and / or VSD positions in a way that maintains a safe fuel / air ratio. This is typically
accomplished by increasing air, fuel and VSD (if equipped) in a stepwise rotation. Keep
increasing the firing rate in this manner until high fire positions of the actuators / VSD are
reached.
NOTE: Typically, the gas pressure regulator immediately upstream of the firing rate control
valve will need to be adjusted on a new installation. Adjust the regulator such that the firing
rate control valve is between 60‐80 degrees open at high fire.
6. Once high fire actuator / VSD positions and gas pressure regulator(s) are set, record actuator /
VSD positions, burner head pressure, high fire fuel flow, and gas pressure upstream of the firing
rate control valve. After this is recorded, the burner can be shut down.
7. With the burner off, go back to Point 1. When Point 1 is entered, the AZL will prompt to
"change" or "delete" the point. "Delete" should be selected, and Point 1 should be deleted.
8. Now that low fire and high fire fuel flows have been established and the gas pressure regulator
has been set, the Ratio Control Curves can be laid out using fuel flow. If fuel flow is not
available, burner head pressure can be used as a last resort. The curves can be laid out using
paper and a calculator, or a free excel spreadsheet is available for this purpose. This
spreadsheet, called the "LMVx Curves Spreadsheet", can be found at www.scccombustion.com.
The next page shows how the "LMVx Curves Spreadsheet" used to set up a 600 BHP steam
boiler with FGR (Aux 3 actuator) and a VSD. This is an example to illustrate what a typical setup
might look like, and is not intended to be copied verbatim to an LMV5 in the field.
NOTE: Up to 15 curve points can be entered; however, 10 points are recommended for most
applications.
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