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Startup sequence (cont´d)
t4
Interval «BV1 – BV2» or «BV1 - LR»
On completion of «t4», voltage is present at terminal 19
The voltage is required to power «BV2» connected to auxiliary switch «v» in the actuator
t5
Interval
On completion of «t5», terminal 20 receives power. At the same time, control outputs 9 to 11 and input 8
are galvanically separated from the LAL's control section
LAL is now protected against reverse voltages from the load control circuit
With the release of «LR» at terminal 20, the startup sequence of the LAL ends
After a few idle steps the sequence switch switches itself off. That is, the idle steps do not cause any
change in the contact position.
B
Operating position of the burner
B-C
Burner operation
During burner operation, «LR» drives the air damper to the nominal load or low-fire position, depending
on heat demand
Release of the nominal load takes place via auxiliary switch «v» in the actuator
In the event of loss of flame during operation, the LAL will initiate lockout
For automatic start repetition, the clearly marked wire link «B» on the plug-in section of the LAL must be
cut away
C
Controlled shutdown
In the case of controlled shutdown, «BVx» will immediately be closed. At the same time, the sequence
switch is started to program «t6».
C-D
Sequence switch travels to start position «A»
t6
Postpurge time
Fan «M2» connected to terminal 7
Shortly after the start of «t6», terminal 10 receives power
air damper is driven to the «MIN» position
Full closing of the air damper starts only shortly before «t6» has elapsed
initiated by the control signal at terminal 11
During the following burner off time, terminal 11 is live
t13
Permissible afterburn time
During «t13», the flame signal input may still receive a flame signal
no lockout
D-A
End of control program
start position
As soon as the sequence switch has reached the start position – having thereby switched itself off – the
flame detector and flame simulation test will start again.
During burner off times, the flame supervision circuit is live.
When the start position is reached:
With LAL1, a voltage signals is fed to terminal 4
With LAL2 / LAL3, a voltage signal is fed to terminal 12
14/24
Building Technologies Division
CC1N7153en
21.09.2016
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