Siemens LMV50 Series Manual page 290

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Building Technologies
Attention!
If at an dual-fuel burner the FGR function is used for only one fuel (e.g. gas
operation with FGR and oil operation without FGR) pay attention to the
following:
When the fuel selection is switched over to the fuel without FGR it must be
assured that the FGR actuator is closed and is supervised kept in the closed
position.
This is accomplished by making the following settings for the fuel without FGR:
∂
Activation of the AUX3 actuator
∂
Parameterization of the positions Home, Prepurge , Ignition and Postpurge
to closed
∂
Parameterization of all AUX3 actuator positions at all curve points to closed
∂
Parameterization of the FGR operating mode to Aux3onCurve
Attention!
The LMV52.4 was specially developed for temperature-compensated flue gas
recirculation.
The LMV52.4 is not suitable for performing combustion air temperature
compensation.
The LMV5 supports 2 different flue gas recirculation (FGR) functions:
1. Flue gas recirculation (FGR) without temperature compensation (operating mode
flue gas recirculation (FGR) = time or temperature).
With these operating principles, the positions of auxiliary actuator 3 can only
change between CLOSED (ignition position) and the positions on the ratio control
curves.
The point in time transition from the ignition position to a position on the ratio
control curve takes place depends either on the progression of the parameterized
time (ThresholdFGR Oil) or the point in time the parameterized temperature
threshold is reached (ThresholdFGR Gas / ThresholdFGR Oil).
2. Flue gas recirculation (FGR) with temperature compensation (operating mode flue
gas recirculation (FGR) = Temp.komp. or TCautoDeact).
With temperature-compensated flue gas recirculation (FGR), the amount of flue
gas fed back is also affected by the flue gas temperature.
With this operating principle, the positions of auxiliary actuator 3 can lie between
the parameterized minimum position (DeactMinPos) and the calculated positions.
Calculation of the positions is based on the value pairs Operating temperature and
associated positions of the ratio control curve plus the Current flue gas
temperature.
3. LMV51.3 and LMV52.2 only provide flue gas recirculation (FGR) without
temperature compensation.
The LMV52.4 also features flue gas recirculation (FGR) with temperature
compensation.
Air actuator
M
Optional
T
auxiliary
actuator 1
or 2
Figure 126: Typical application example
Basic Documentation LMV5...
20 Flue gas recirculation (FGR) function (LMV50/LMV51.3/LMV52)
7550z25e/0511
Auxiliary actuator 3
LMV52...
CC1P7550en
22.05.2018