27
function).
Adjustment of the minimum drop-out voltage
of burner relay. Potentiometer P2.
The minimum drop-out voltage is controlled by a
potentiometer P2, varying between 0 % and 40
% of the input control signal.
Example
•
An input control signal of 0 to 10V DC and
potentiometer P2 set at 0% results into a
drop-out voltage of 0.3V DC.
•
An input control signal of 0 to 10V DC and
potentiometer P2 set at 40 % results into a
drop-out voltage of 4V DC.
Adjustment of the maximum hold-in voltage
of burner relay. Potentiometer P3.
The maximum hold-in voltage is controlled by a
potentiometer P3. Its proportional value is added
to the P2 setting value.
Example:
•
Potentiometer P2 is set at 0 %, and P3 at
5%, the hold-in voltage of the burner relay is
adjustable between 5 % and 100 % of the
input control signal. So, if input control sig-
nal is set at 0 to 10V DC, the hold-in voltage
of the relay amounts to 0.5V DC.
•
Potentiometer P2 is set at 40 %and P3 at
5%, the hold-in voltage of the burner relay is
adjustable between 45 %and 100 % of the
input control signal. So, if the input control
signal is set at 0 to 10 VDC: the hold-in
voltage of the relay amounts 4.5V DC.
Adjustment of the current control.
Potentiometer P1
The control current or voltage of one or two
Honeywell modulation coils V7335A Modureg is
controlled by the potentiometer PI, varying
between 50 % and 100 % of the input control
signal.
Example:
•
Maximum power (165 mA-DC
at 22V DC) is
provided to the modulation coil with a 10V
DC input control signal and P1 set at 100 %
•
Maximum power (165mA-DC at 22V DC) is
provided to the modulation coil with a 5V DC
input control signal and potentiometer PI set
at 50 %.
61
62
6
3
64
6
5
6
6
01
02
03
05
0
6
P2
P3
P1
12
LN
230V
50
Hz
230V
H
IGH
F
IRE ST
AR
T
HE
AT
DE
MA
ND
V733
5A
VAL
VE
+-
+
+
+
0-5V
0-1
0V
4-2
0mA
MA
XI
M
U
M
MINIM
U
M
CU
RRE
NT
0
100
5
100
50
100
6. Commissioning & Testing cont.
High fire start signal:
A maximum control current
or voltage is sent to the
modulation coil for 10s
when a 230V AC line input
voltage
appears
on
terminal 3.
This 230V AC line input
voltage is generated by a
contact in the burner relay
incorporated within the
appliance.
When opening the main
gas
valve
and
when
ionisation
current
is
sufficient, the 230V AC line
input voltage is directed
towards terminal 3 of the
interface board.
