10
Concord ESi
- Installation and Servicing
GENERAL
6
OPERATION OF THE BOILER FITTED WITH THE RV 00 541 400 00
SAFETY CONTROL BOX
OPERATING PRINCIPLE
The boiler can operate either in the 2nd or in the 1st stage,
depending upon the heat requirements of the installation.
The burner ignition and monitoring cycle is performed by the
safety control box.
When heating is required, the boiler thermostat
TCH1
closes
the contact. After a time delay
tw
, the ignition transformer
TA
produces a number of sparks at the ignition electrode and,
after a pre-ignition delay
tvz
, the ignition burner valve
VG
and
the safety valve
VS
open.
A flame appears at the ignition burner and the ionisation probe
SF
detects a flame signal with a minimum ionisation current of
1
μ
A. After the ionisation current has stabilised, the main
burner 1st stage
BR1
(or 2nd stage
BR1 + BR2
if the 2nd stage
thermostat
TCH2
requires heating) starts.
BEHAVIOUR IN ABNORMAL CONDITIONS
-
If the flame is not detected before the end of safety time
ts
,
the safety control box goes to lockout and the red indicator
on the control panel lights up and remains on until it is
reset manually.
-
If the flame is lost during normal operation, the safety
control box automatically repeats the start-up sequence. If
the flame is not re-established then, the control box will
lockout.
RESETTING
If at lockout, the safety control box is reset by pressing the reset
button. If the first resetting does not give the expected result,
wait for at least 15 seconds
before resetting once again.
Note 1
When it is started up for the first time, the safety control box
may be in safety position: press the reset button to release it.
Note 2
If the resetting button is pressed during normal operation, the
gas valves close and the safety control box starts up a new
sequence.
A
: Beginning of start-up operation
B
: Flame established at the ignition burner and
start-up of the main burner
BR1
: 1st stage
BR2
: 2nd stage
D
: Safety device goes to lockout because
there is no flame signal
SF
: Ignition burner flame signal
TA
: Ignition transformer
TCH1
: 1st stage boiler thermostat
TCH2
: 2nd stage boiler thermostat
ts
: Safety time, max. 10 seconds
tvz
: Pre-ignition
tstab
: Flame stabilisation time (5 s)
time (10 s.)
tw
: Waiting time (5 s.)
VA
: Alarm and safety control box lockout
indicator
VG
: Ignition valve + safety valve
VS
- Normal operating cycle
Safety box output signals
Required control signal
2nd stage operation
Call for 2nd stage heating
Operating cycle (switching the safety control box
off while starting to check absence of flame signal)
CON9071