Auxiliary Functions; Warning When Flue Gas Temperature Is Too High; Combustion Efficiency - Siemens LMV50 Series Manual

Building Technologies

19.7 Auxiliary functions

19.7.1 Warning when flue gas temperature is too high

If a flue gas temperature sensor is connected and activated, a warning is delivered in
case the adjusted flue gas temperature is exceeded. Excessive flue gas temperatures
are an indicator of increased boiler losses ⇑ boiler should be cleaned. The warning
threshold for gas- and oil-firing can be set separately.
Parameter MaxTempFlueGas Gas
MaxTempFlueGas Oil

19.7.2 Combustion efficiency

If a QGO20, a combustion air and flue gas temperature sensor are connected and
activated, the combustion efficiency is calculated and displayed.
To ensure that the calculation is made correctly, the fuel parameters must be selected
and set in accordance with the type of fuel.
Also refer to chapter Parameterization of type of fuel.
The calculation is made according to the following formula (1. BimSchV = 1. Bundes-
Imissionsschutzverordnung = First Federal Imission Protection Decree):
Flue gas volume ratio:
O2 value dry:
Flue gas losses:
Efficiency:
Parameter Combustion air temperature sensor (NoSensor, Pt1000, LG-Ni1000)
Flue gas temperature sensor (NoSensor, Pt1000, LG-Ni1000)
As an alternative to connecting the supply air temperature sensor at input X87 of the
PLL52, it can also be connected at input X60 of the LMV52. To do this
AirTempX60PT1000 must be activated.
Parameter AirTempX60PT1000 (deactivated, activated)
Basic Documentation LMV5...
19 O2 trim control with LMV52 and PLL52
V_afNmin
AVft <
V_atrNmin
AVft O2ContentAir
O2_tr =
O2ContentAir
O2Value_Wet
∑
A2
<  
qa
O 2 ContentAir

γ
< ,
100 % qa
F
+ AVft - 1
⌡
∋
Ι
∗ ∂  
B
flue gas
,
O 2 _ tr

CC1P7550en
(
Ι
,
su pply air
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22.05.2018