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Siemens Building Technologies Basic Documentation LMV5... CC1P7550en
HVAC Products 19 Addendum 4: LMV52... with O2 trim control and O2 module 13.08.2004
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
Parameter: MaxTempFlueGas Oil
19.7.2 Combustion efficiency
If an O
2 sensor, a combustion air and flue gas temperature sensor is connected and
activated, the combustion efficiency will be calculated and displayed.
Parameter: Combustion air temperature sensor (NoSensor, Pt1000,
LG-Ni1000)
Parameter: Flue gas temperature sensor (NoSensor, Pt1000, LG-Ni1000)
To ensure that the calculation will be made correctly, the fuel parameters must be se-
lected and set in accordance with the type of fuel burnt.
Also refer to section 19.10.2 Parameterization
The calculation is made according to the following formula (1. BimSchV = 1. Bundes-
Imissionsschutzverordnung = First Federal Imission Protection Decree):
Flue gas volume ratio:
V_atrNmin
V_afNmin
AVft =
O2 value dry:
O2_tr =
AVft O2ContentAir
O2ContentAir
O2Value_Wet
+ AVft - 1
Flue gas losses:
()
airpplysugasflueB
trOContentAirO
A2
qa
ϑϑ
−•
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
+
−
=
_22
Efficiency:
qaF
%100
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