Siemens LMV5 Series Technical Instructions page 193

LMV Series
O2MaxManVariable and O2MinManVariable – These parameters set how much the O
in an attempt to achieve the O
O2MaxManVariable sets how much the system can increase the air rate. Likewise, O2MinManVariable
sets how much the system can decrease the air rate.
Menu path: Params & Display > O2Contr/Alarm > Gas Settings > Control Param
These trim limits must be set so that the O
should not be set in a way that allows the burner to run at an unsafe fuel‐air ratio.
Ideally, the O trim system must compensate for two main environmental conditions. These conditions
2
are ambient air temperature and barometric pressure. Figure 6‐8 illustrates how much the manipulated
variable needs to change to compensate for these environmental conditions. The chart in Figure 6‐8
and the example in Figure 6‐9 serve as a guideline for setting the O2MaxManVariable and
O2MinManVariable parameters.
Figure 6‐8: Theoretical Change of the Manipulated Variable with Changes in Ambient Temperature
When the O Control Curve is commissioned, all burners will be at (0, 0) on the chart, where the X‐axis
2
and Y‐axis cross. As air temperature and barometric pressure change from the air temperature and
SCC Inc.
setpoint ‐ essentially the trim limits for the O
2
system can achieve the O
2
and Pressure
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Technical Instructions
Document No. LV5‐1000
system can trim
2
system.
2
setpoint. However, the limits
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Section 6