Siemens LMV51 Series Basic Documentation page 276

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HVAC Products
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 sensor, a combustion air and flue gas temperature sensor is connected and
2
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:
O2 value dry:
Flue gas losses:
Efficiency:
Basic Documentation LMV5...
19 Addendum 4: LMV52... with O2 trim control and O2 module
V_afNmin
AVft =
V_atrNmin
AVft O2ContentAir
O2_tr =
O2ContentAir
O2Value_Wet
⎛
A2
= ⎜ ⎜
qa
⎝
O 2 ContentAir
η
= −
100 % qa
F
+ AVft - 1
⎞
(
ϑ
+ • ⎟ ⎟
B
flue gas
−
⎠
O 2 _ tr
)
ϑ
−
su pply air
CC1P7550en
13.08.2004