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Building Technologies Division CC1N7153en
21.09.2016
Function
2-stage expanding flame burner
Legend
BV... Fuel valve
FS Flame signal amplifier
LK Air damper
LR Load controller
M... Fan or burner motor
R Control thermostat or pressurestat
RV Modulating fuel valve
Z Ignition transformer
A Start command by «R»
B Operating position of burner
B-C Burner operation
C Controlled shutdown
C-D Sequence switch travels to start position «A», postpurging
D-A End of control sequence
t1 Prepurge time with air damper open
t3 Preignition time
t4 Interval fuel valve 1 (BV1) - fuel valve 2 (BV2) or fuel valve 1
(BV1) - load controller (LR)
t5 Interval between voltage at terminal 19 and terminal 20
t6 Postpurge time
t7 Interval between start command and power at terminal 7
t11 Air damper running time to the OPEN position
t12 Air damper running time to the low-fire position
t13 Permissible afterburn time
TSA Ignition safety time
FS
BV2
min.
LK
0...
M
R
100%
LR
BV1
M1
M2
Z
~
M
P
R
T
t12
t4
t16
t5
A
B
CD
t11
t13
t6
t7 t1
t3
t3n
TSA
t3´
7153a09/0498
Modulating expanding flame burner
R
LR
t5
t11
t12
t13
FS
min.
LK
0...
M
100%
RV
A
BV1
M2
Z
~
M
P
R
M1
T
t4
t3
t7
t1
TSA
B
t6
C
D
7153a10/0498
The following features of the LAL afford a high level of safety:
Detector and flame simulation test are restarted on completion of the afterburn time
«t13». Open or not fully closed fuel valves immediately initiate lockout at the end of
afterburn time «t13». The test ends on completion of the prepurge time «t1» of the
next startup sequence
The correct functioning of the flame supervision circuit is automatically checked
during each burner startup sequence
The control contacts for the release of fuel are checked to ensure they have not
welded postpurge time «t6»
A built-in unit fuse protects the control contacts against overloads
General
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