52/69
Siemens Building Technologies
Electronic Air / Fuel Ratio Control System
CC1P7873.1en
HVAC Products
16 Applications
15.10.2002
16.2 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 with O
2
trim control)
20
Q
RWF40
LAL2.../LFL1.../
LGK16.../LOK16...
13
5
Q13
Y1
Y2
11
10
9
Q14
14 4
8
12
7
RVW25
Q5 Q1
Y20 Y10
L
Q3A
Q2
N
H
AL1
L
N
W
B1
M X1
M
RVW26
Q5
Q1
Y20 Y10
L
Q3
U10 B4 M Y5
Y6
AUX2
U10 B2 M Y3
Y4
AUX1
1
2
SA5
SA7
Q2 N
H
1
2
M
F1
1K9
Y8
M
AL2
78731f05/0801
X3
M
FU
1K8
M
X3
U1
M
U3
Q3B
1K4
S1
F1
F2
1K2
1K4
F1
F2
F2
Q7
X2
GND
RPO25
F1
F2
Q3
Q2B
Q2A
Q6
X2
X2
U1
DC-
P
ow
e
r
St
ar
t /
S
top
M
In
0
...1
0
V
1K9
EK
1K2
1K4
1K4
Q4
Q4
AGK34
TG
Y7
1K8
P
LP
1K2
BV-F2
18
1K2
BV-F1
TXD RXD GND
TXD
RXD
GND
Fig. 27
Basic diagram with O
2
trim control
The following contacts are included in the burner control’s start control loop:
The on / off contact of the load controller (Q13...Q14), the readiness contact of the
RVW25... and RVW26… (Q4...Q5), the readiness contact of the RPO25... (Q6...Q7),
and the limit thermostat.