Siemens LMV52.240B1 - Observing the Behavior of the O 2 Trim

TechnicalInstructions  LMVSeries
DocumentNo.LV5‐1000
Section6 Page24SCCInc.
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O2InitOffset‐Fortheotherthreestartmodesotherthan"standard",thisisarichorleanbiasthatis
appliedtothete mperaturecompensation.Negativevalues(‐2to‐0.1)willbiasthetemperature
compensationmorerich,andpositivevalues(0.1to2)willbiasthetemperaturecompensationmore
lean.Notethattheunitsonthisare%O
2
,soasettingof‐2willoffsettheO
2
approximately2%more
rich.ThisoffsetisdissolvedaftertheO
2
trimbecomesactive(NumberTauSuspendexpires).
Menupath:Params&Display>O2Contr/Alarm>GasSettings>Startmode
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ObservingtheBehavioroftheO
2
Trim
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AftertheO
2
curvesarecommissionedandpostcommissioningtuningisdone,thebehavioroftheO
2

trimcanbeobservedandevaluatedtodetermineiffurthertuningisnecessary.
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CurrentO2ValueandO2Setpoint
Menupath:Operation> O2Module
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ParameterscanbetoggledbetweentoseehowwelltheO
2
setpointisbeingfollowedatdifferentfiring
ratesandwhentransitioningbetweenfiringrates.
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Expectedbehavior:thedifferencebetweentheO
2
setpointandactualvalueshouldbeslightlymore
whentheburneristransitioningbetweenfiringratesandlesswhennottransitioning.Asaguideline,
thedifferenceshouldbelessthan+/‐0.2%O
2
whennottransitioningandlessthan+/‐0.4%O
2
when
transitioning.

ManVarO2Ctrl
Menupath:Params&Display>O2Contr/Alarm>ProcessData
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Thisparametershowstheamountoftrim.Thevalueshownisdefinedbelow:
1. Avalueof50%indicatesnotrimming.
2. Valuesgreater than 50%‐moreairisneededtoachieveO
2
setpointcomparedtowhentheO
2

ControlCurvewascommissioned.
3. Valueslessthan50%‐lessairisneededtoachieveO
2
setpointcomparedtowhenO
2
ControlCurve
wascommissioned.
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Expectedbehavior:shouldstayrelativelyconsistentfromlowfiretohighfire.Shouldchangewith
externalchangessuchascombustionairtemperature,barometricpressure,draft,heatingvalueoffuel,
airfiltersbecomingdirty,etc.
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StateO2Ctrl
Menupath:Params&Display>O2Contr/Alarm>ProcessData
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ThisparametersidentifiesthestateoftheO
2
control.Possiblevaluesare:
1. Deactivated–theO
2
controlwaseithermanuallyorautomaticallydeactivated
2. Locked–themanipulatedvariable(amountof trim)isbeingheldatthelastvalue
3. LockTStart–O
2
controliswaitingtoengageafter light‐off(waitingforNumberTauSuspendto
expire)
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