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Building Technologies
Basic Documentation LMV5...
CC1P7550en
19 O2 trim control with LMV52 and PLL52
22.05.2018
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:
V_atrNmin
V_afNmin
AVft
<
O2 value dry:
O2_tr =
AVft O2ContentAir
O2ContentAir
O2Value_Wet
+ AVft - 1
Flue gas losses:
∋
(
air
pply
su
gas
flue
B
tr
O
ContentAir
O
A2
qa
Ι
Ι
,
∂
⌡
∑
∗
,
<
_
2
2
Efficiency:
qa
F
,
<
%
100
γ
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)