112/232
Building Technologies Boiler Sequence Controller RMK770 CE1P3132en
HVAC Products 7 Boiler control 23.04.2009
Owing to the performance of the temperature-time integral, it is not only the period of
time that is considered, but also the extent of overshoot. This means that when the
overshoot is significant, burner stage 2 is locked earlier. When the reset integral (area
“b” in the diagram) has reached the set value of the reset integral of stage 2 (point in
time t
reset
), burner stage 2 is locked and the basic stage switched off.
1
0
INT
max.
RlsBSt2
1
0
BSt2
t
RlsINT
3131D06
0
1
0
t
t
t
t
BSt1
max.
TBoSp+
1
/
2
SDBo
TBo
RstINT
TBoSp-
1
/
2
SDBo
RstINT
BSt1 Burner stage 1
BSt2 Burner stage 2
INT Integral
Rls Release
Rst Reset
SD Switching differential
Sp Setpoint
t Time
Tbo Boiler temperature
If, with stages 1 and 2 released, both stages are locked at the same time, the basic
stage is switched off with a delay of 10 seconds. Switching off in 2 phases also reduces
the pressure shocks in the gas supply line. This prevents unnecessary lockout in the
case of large burner capacities.
7.8.4 Control of modulating burners
Main menu > Commissioning > Settings > … or
Main menu > Settings > Boiler … > Burner modulating
Operating line Range Factory setting
Actuator running time
1…600 s 60 s
P-band Xp
1…100 K 20 K
Integral action time Tn
0…600 s 150 s
Derivative action time Tv
0…30 s 5 s
Modulating burners operate in modulating mode only above a certain level (for normal
forced draft burners, this limit is about 30 to 40% of the rated capacity).
Note
To Next Page
Loading...
