Gas Valve Proving; Recommendation - Siemens LMV5 Series Basic Documentation

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4.2.2 Gas valve proving

Gas valve proving is only active when firing on gas.
When a leak is detected, the gas valve proving function ensures that the gas valves will
not be opened and that ignition will not be switched on. Safety shutdown will take place.
V1 V2
PS
VP
Mains
V1 V2 PS-VP
t80 Evacuate
t81 Atm. test
t82 Fill
t83 Pressure test
It is possible to parameterize whether gas valve proving shall be performed. Also, the
time can be set. Gas valve proving can be carried out during startup, shutdown, or in
both phases.
Perform gas valve proving during shutdown.
Parameter:
ValveProvingType (No VP / VP startup / VP shutdown / VP
stup/shd)
The evacuation and filling times as well as the test times at atmospheric pressure or
mains pressure must be set by the OEM, for each individual plant and in accordance
with the requirements of EN 1643.
Parameter:
VP_EvacTme
Parameter:
VP_TmeAtmPress
Parameter:
VP_FillTme
Parameter:
VP_Tme_GasPress
In particular, it must be ensured that the 2 test times will be set correctly. It must also
be checked whether - on the specific application - it is permitted to introduce into the
combustion chamber the gas required for testing.
The test times are safety-related.
After a reset, or in the event gas valve proving has been aborted or prevented, the
burner control will carry out gas valve proving during the next startup sequence (only if
gas valve proving is activated).
Examples of aborted gas valve proving:
When the safety loop or the start prevention input for gas (containing Gpmin) opens
during gas valve proving.
If gas valve proving is parameterized with «startup and shutdown», the gas valves
must perform additional switching cycles. This means that wear and tear of the gas
valves will increase.
Basic Documentation LMV51...
4 Burner control
With gas valve proving, first the gas valve on the
burner side is opened to bring the test space to
atmospheric pressure.
After the valve has closed, the pressure in the test
space may not exceed a certain level.
Then, the gas train is filled by opening the gas valve
on the gas network side.
After shutting the gas valve, the gas pressure may not
drop below a certain level.
CC1P7550en
01.10.2003