TC · Edition 08.17
25
Function
3 .1 .6 Test instant for Mode 2: testing after burner run
t
M
5s
10s
15s
20s
25s
30s
Mode 2
The tightness test after burner run begins as soon as
the burner is switched off.
To ensure that the valves are checked for tightness once
before starting up the system, the tightness test runs
when the mains voltage (L1) is applied or after a reset. If
the valves are tight, the LEDs
1
2
Power
and
1
2
Power
are green.
The OK enable signal is not forwarded to the automatic
burner control unit until the thermostat/start-up signal
ϑ
and the safety interlock input signal
OK
V1
V2
have been applied.
The tightness test after burner run starts when the
thermostat/start-up signal
ϑ
drops. The OK enable sig-
nal is only forwarded to the automatic burner control
unit again once the thermostat/start-up signal
ϑ
and
the safety interlock input signal
OK
V1
V2
have been re-applied.
The tightness test is valid for 24 hours. If the thermo-
stat/start-up signal
ϑ
and the safety interlock input
signal
OK
V1
V2
are connected during this time, a new tight-
ness test must not be carried out before burner run and
the OK enable signal is set. However, if the 24 hours
have elapsed, a new tightness test is carried out before
burner run.
L1 (+)
ϑ
TEST
OK
Mode 2
t
t
1
10
6
12
L1 (+)
ϑ
TEST
OK
1
10
6
12
1
2
1
2
TEST
don’t-care
5
t
p
t
p
t
p
5
V1 undicht
V2 undicht
Leaks
If the tightness control TC detects a leak on one of the
two valves, the red LED lights up for a fault on valve V1
1
2
Power
or valve V2
1
2
Power
. A fault is signalled externally
,
e.g. by switching on a buzzer or a warning light.
L1 (+)
ϑ
TEST
OK
Mode 2
t
t
1
10
6
12
L1 (+)
ϑ
TEST
OK
1
10
6
12
1
2
1
2
TEST
don’t-care
5
t
p
t
p
t
p
5
V1 leaking
V2 leaking