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Diagram of switching mechanism
Legend
Remote lockout indication Alarm
AL
AS
Unit fuse
Main relay with contacts «ar...» Working relay
AR
BR
Lockout relay with contacts «br...»
BVx
Fuel valve
d1/d2
Contactor or relay
EKx
Reset button
IONx
Ionization probe
FR
Flame relay with contacts «fr...»
GP
Gas pressure switch
H
Main isolator
L1
Lockout warning lamp
LK
Air damper
LP
Air pressure switch
LR
Load controller
M1/M2
Fan or burner motor
NTC
NTC resistor
R
Control thermostat or pressurestat
SA
Air damper actuator
a: Changeover limit switch for actuator's OPEN position
z: Changeover limit switch for actuator's CLOSED position
SB
Safety limit thermostat
Si
External primary fuse
SM
Synchronous motor of sequence mechanism
V
Flame signal amplifier
(1)
Input for forced energizing of the flame relay during the
functional test of the flame supervision circuit
(contact «XIV») and during safety time (TSA) (contact
«IV»)
W
Limit thermostat or pressure switch
Z
Ignition transformer
10/11
Building Technologies Division
A
t1
a
I
b
t7
a
II
b
III
a
b
IV
a
V
a
VI
b
a
VII
b
a
VIII
b
a
IX
a
X
a
XI
b
t10
a
XII
b
a
XIII
b
a
XIV
b
a
XV
b
t3
t4
t8
t9
TSA
7454d01/0204
Output signals of burner control
Required input signals
A
Start command given by the control thermostat
A-B
Startup sequence
B
Operating position of burner
B-C
Burner operation
C
Controlled shutdown by control thermostat or pressurestat (R)
C-D
Sequence mechanism runs to the end position after a
controlled shutdown by control thermostat or pressurestat (R)
End position of burner Corresponding to the start position
D
Switching times in seconds
TSA
Ignition safety time
t1
Waiting time or prepurge time
t3
Preignition time
t4
Interval fuel valve (BV1-BV2)
t5
Interval between release of the 2
controller (if present)
t6
Postpurge time
t7
Interval until voltage at terminal 7 is present
t8
Duration of startup program
nd
t9
2
safety time for 2
t10
Interval until air pressure check is started
t20
Steps of switching mechanism with no change in the
program Idle steps
B
C
t6
t5
t20
nd
fuel valve and the load
nd
stage
D
12
7
19
16
9 10
20
11
8
18
15
23 24
12
7
4 s
14 s
2 s
8 s
10 s
10 s
2 s
36 s
8 s
6 s
26 s
CC1N7454en
20.11.2017
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