IFD 258 · Edition 10.09
29
7 .15 Two-stage burner control with two solenoid
valves
The IFD is equipped with two signalling contacts for operating
and fault signals. For controlling two-stage burners, a bridge
must be installed in the lower section of the housing between
terminals 12 and 13. Valve V2 is connected to terminal 14.
I
Z
c
V1
V2
13 14
PE
max. 2 A,
253 V~
ϑ
1 2 3 4 5 6 7 8 9 10 11 12
230V
L1 (L1)
N (L2)
s1
s2
v2
v1
F1
13 14
max.
2 A,
253 V~
IFD 258
Program sequence
tW
t
1
3
10
11
5
8-9
14
ϑ
L1
tZ
tSA
88
04
02
01
V1
V2
During the waiting time t
W
after heat demand, checks are
made for flame simulation and fail-safe operation. If no flame
simulation is detected, the IFD 258 opens the gas valve V1 and
ignites the burner. The ignition time t
Z
is constant. The safety
time t
SA
starts with the ignition time t
Z
. If a flame is detected
during the safety time, the operation signalling contact closes
and valve 2 is opened once the safety time t
SA
has elapsed.
If no flame is detected, the fault signalling contact closes once
the safety time t
SA
has elapsed.
Example of application
Control: ON/OFF or ON/HIGH/LOW/OFF
The burner BIO/BIC starts at low-fire rate. Once the normal
operating state is reached, the automatic burner control unit
IFD 258 opens the air valve. The burner switches to high-fire
operation.
IFD 258
10
µC
BIO/
BIC
VR..R
11
8
9
13
14
5
GIK..B
VAS
12
7 .16 Short-circuit fuse
In accordance with EN 298, all safety outputs for gas valves are
fitted with an internal fuse, which may no longer be replaced.
In the event that the internal fuse blows, the unit must be sent
to the manufacturer for inspection.
Project planning information
