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BCU 460, BCU 465 · Edition 11.19
140
Legend
22 Legend
Ready for operation
Safety interlocks (limits)
Control element position check
Controlled air flow
Remote reset
LDS
Safety limits (limits during start-up)
Gas valve
Air valve
Air/gas ratio control valve
Burner
P
Purge
A
External air valve control
Operating signal
Fault signal
Start 1 Start-up signal (BCU)
FLO
Input for Flameless/menox
®
mode signal
HT
Input for high temperature operation
PZ
Pressure switch for tightness control (TC)
PZH
Pressure switch for maximum pressure
PZL
Pressure switch for minimum pressure
PDZ
Differential pressure switch
M
Actuator with butterfly valve
TC Tightness control
p
u
/2 Half of the inlet pressure
p
u
Inlet pressure
p
d
Outlet pressure
V
p1
Test volume
GZL
Valve with proof of closure switch
Three-point step switch
Input/Output, safety circuit
I
N
Current consumption of sensor/contactor
t
L
Tightness control opening time
t
M
Measurement time during tightness test
t
P
Tightness control test period (= 2 x t
L
+ 2 x t
M
)
t
FS
Flame proving period
t
MP
Minimum pause time
t
NL
Over-run time
t
SA
Safety time on start-up
t
SB
Safety time during operation
t
VZ
Pre-ignition time
t
PV
Pre-purge time
t
RF
Controller enable signal delay time