Valve Proving Via Pressure Switch-Min-Gas X5-01; Lockout Phase (Phase 00); Safety Phase (Phase 01) - Siemens LMV37.4 Series Basic Documentation

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6.5.2.2.

Valve proving via pressure switch-min-gas X5-01

P
GP
Bild 295e/0309
Figure 26: Valve proving via pressure
switch-min-gas
When making the valve proving test via pressure switch-min-gas, the impact on the
program sequence is as follows (see Sequence diagram G ):
a) Valve proving on startup
In place of sampling pressure switch-min-gas (gas shortage test) in phase 22, it
is sampled during the time valve proving is performed at the end of the filling
time.
b) Valve proving on shutdown / deactivated
Pressure switch-min-gas is sampled at the end of preignition. For that purpose,
a new phase 39 (Test Pmin ) is introduced and evaluation of gas shortage is
made at the end of the phase (duration of phase = filling time). In practice, this
represents a prolongation of preignition by the filling time, if valve proving via
pressure switch-min-gas was selected.
The valve proving test can only be made via pressure switch-min-gas, which must be fit-
ted between the valves. This has an impact on the control sequence (see Sequence
diagram). Valve proving is still activated via parameter 241.
6.5.2.3.

Lockout phase (phase 00)

The relays of the fuel valves and the safety relay (fan) are de-energized, the alarm relay
is energized and lockout takes place. This means that phase 00 can only be quit via a
manual reset. The time of phase 00 is unlimited.
6.5.2.4.

Safety phase (phase 01)

The safety phase is an intermediate phase which is completed prior to triggering lock-
out. The relays of the fuel valves and the safety relay (fan) are de-energized, but lockout
does not yet take place. The alarm relay is not yet activated. If possible or permitted,
safety checks or repetition counter checks are made whose results decide on the transi-
tion to Lockout phase or Standby. The duration of the safety phase is dynamic (depend-
ing in the extent of testing), the maximum time being 30 seconds.
This process is aimed primarily at avoiding unwanted lockouts, e.g. resulting from EMC
problems.
Basic documentation LMV37.4...
6 Basic unit
When performing valve proving, the gas valve on the
burner side is opened first to bring the test space to at-
mospheric pressure. Then, the valve is closed where-
upon the pressure in the test space must not exceed a
certain level. Then, the gas valve on the mains side is
opened to fill the gas pipe. When the valve is closed
again, the gas pressure must not drop below a certain
level
t80 Evacuation (P242)
t81 Atmospheric test (P243)
t82 Filling (P244)
t83 Pressure test (P245)
V... Fuel valve
GP Gas pressure switch
Signal ON
Signal OFF
Permissible signal
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CC1P7546en
01.12.2009