51/69
Siemens Building Technologies
Electronic Air / Fuel Ratio Control System
CC1P7873.1en
HVAC Products
16 Applications
15.10.2002
16 Applications
16.1 Basic diagram of a plant with a modulating
burner (one type of fuel)
(Using the LAL..., LFL1..., LGK16... or LOK16... as a burner control and the
RWF40... as a load controller)
20
Q
RWF40
LAL2.../LFL1.../
LGK16.../LOK16...
13
5
Q13
Y1
Y2
11
10
9
Q14
14
12
7
RVW25.000B27
Q5 Q1
Y20 Y10
L
Q3A
Q2
N
H
AL1
L
N
W
EK
B1
M
X1
M
RVW26.000B27
Q5
Q1
Y20 Y10
L
Q3
U10 B4 M Y5
Y6
U10 B2 M Y3
Y4
Q2 N
H
F1
Q4
1K9
Y8
AL2
X3
M
X3
M
Q3B
18
BV
DC-
P
owe
r
In
0.
..1
0
V
M
FU
M
78731f04/0801
U1
U3
1K9
1K8
AUX2
AUX1
1
2
SA5
SA7
1
2
M
M
Q4
F1
8
4
AGK34
TG
Y7
1K8
LP
P
St
ar
t /
St
op
TxD RxD GND
TxD
RxD
GND
Fig. 26
Basic diagram with a modulating burner
AL
Indication of nonreadiness
LP
Air pressure switch
BV
Fuel valve
M
Fan motor
EK
Lockout reset button
SA...
Actuator of … damper
FU
Variable speed drive
TG
Tacho-generator
W
Limit thermostat or pressure switch
The following contacts are included in the burner control’s start control loop (terminals
4..5):
·
Readiness contact «Q4...Q5» of the RVW25... and RVW26…
·
The burner’s on / off contact «Q13...Q14» of the load controller
·
Limit thermostat «W» or gas pressure switch
In the event of lockout, the RVW25... and the RVW26… can be reset by pressing lock-
out reset button «EK» in the supply line. Fuel selector «F1» is connected to the line.
Terminal «F2» is not used so that the curves and parametes for fuel 1 are permanently
selected. The variable speed drive acts on the fan speed, «SA2» on the fuel valve.
«SA4», «SA5» and «SA7» are optional auxiliary actuators that can be installed if re-
quired. Signal lamp «AL» can be used for indicating faults of the RVW25... and
RVW26... With power ON of the RVW25... and RVW26... (during the self-test) the lamp
lights up for a short moment.
When sensing terminal «H» with a programmable logic controller, it must be taken into
account that with power ON or after a reset of the RVW25… and RVW26…, nonreadi-
ness or a fault of the RVW25... and RVW26… will be signaled for about 2 seconds.
Legend