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Siemens Building Technologies
Electronic Air / Fuel Ratio Control System
CC1P7873.1en
HVAC Products
5 Description of functions
15.10.2002
5.4 Shutdown
Burner control
Burner control is in its
operating position
If the start control loop opens,
the shutdown sequence is
started.
The fuel valves will shut down
Starts the postpurge time if
required
Switches the fan motor off
Controls the actuators
G
BV1
LKZ
QUIT
LR
+ RVW25
Q1 = 230 V
LR
RVW25
X1
78
73
1
f0
3e/1
2
01
RVW26... is in its operating
position
Identifies burner shutdown.
Responds no longer to load
positioning signals.
Sets Q1 = 0 V
Closes all actuators
When all actuators are closed,
Q1 = AC 230 V indicates
readiness to make a new start
RVW26 Display
Q3
Q2
Y20
Q1
U1
.
-8.-
-9.-
-0.-
TxD
RxD
RxD
TxD
n
= display of burner output on the RVW26...
Note:
The RVW26… identifies the burner control's startup and shutdown sequence from the
control commands.
This control sequence takes place according to a fixed basic pattern (burner control
program).
Departures from this basic pattern will not be accepted by the RVW26… and lead to
lockout.
Do not include contactor or relay contacts in the signal lines!
If this is not possible, make certain that such contacts –
due to delayed signals
–
do not
adversely affect the correct
functioning of the unit
.