30
Leakage Test
Mode of Operation
Integrated Leakage Test (option)
Leakage test flow chart
Integrated leakage test
The leakage test checks whether the main gas valves are leak-tight.
(option)
The supply gas pressure is used for this purpose. Since the leakage test line
(space between the two main valves) burns empty in the event of a shut-off,
this part is normally pressureless when starting (gas pressure > min. = 0).
The FMS checks this. Main gas 1 is then briefly opened and gas flows into the
test line (gas pressure > min. changes from 0 to 1). This pressure must then
subsist for 30 seconds. The leakage test is then deemed to be completed.
If the leakage test line is not empty at the start (e.g. as a result of a fault shut-
off previously), main gas valve 2 is opened first. The leakage test line is thus
vented (into the combustion chamber or over the roof, depending on the
system, for suggested circuit see next page). A check is then conducted to
see whether the line remains pressureless for 30 seconds. Otherwise the
procedure is as described previously.
The leakage test can be performed before ignition and/or after shut-off.
Selection via parameters.
The pressure monitor for the leakage test line must be connected to "Gas
pressure >min” input (terminal 73). It also monitors the minimum pressure
during operation. If another minimum pressure is to be monitored during
operation, however, the pressure monitor is, for this purpose, to be looped into
the gas safety interlock circuit.
The test line, however, must be designed so as to ensure that the test time of
30 sec. per valve is sufficient to reliably detect a leak of 0.1% of the fuel gas
3
consumption at maximum firing heat output, but at least 50 dm /h.
Flow chart
Start
Leak Test
Leak
test line
under pressure
Gas > min = 1
Gas valve 1
(gas line side)
open for 2 sec.
Yes
Yes
1
1
1
1
Pressure
drops again
1
No
No
No
Pressure
rises again
No
Wait 30 sec
and
test pressure
Leak test
successfully
completed
Leak
test line
pressureless ?
Gas > min = 0
Leak
test line
pressureless ?
Parameter
770 = 1
Wait 30 sec
and
test pressure
Fault shut-off
1
Gas valve 2
(burner side)
open for 2 sec.
Yes
Yes