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

P LT
(Pmin)
P LT
(Pmin)
Figure 2: Valve proving via gas pressure switch-
min
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7.5.2.2.

Valve proving via gas pressure switch-min X5-01

Step 1: t80 – evacuation of test space.
Gas valve on the burner side is opened to bring the test space to
atmospheric pressure.
Step 2: t81 – atmospheric pressure test.
When the gas has closed, the gas pressure in the test space must
not exceed a certain level.
Step 3: t82 – filling of test space.
Gas valve on the mains side opens to fill the test space.
Bild 411e/1010
Step 4: t83 – gas pressure test.
When the gas valve has closed, the gas pressure in the test space
must not drop below a certain level.
Legend
t80
t81
t82
t83
V...
Pmin
P LT
When making the valve proving test via gas pressure switch-min, the impact on the
program sequence is as follows (see Sequence diagram G):
a) Valve proving on startup
In place of sampling gas pressure switch-min (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
Gas pressure switch-min 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 an
extension of preignition by the filling time, if valve proving via gas pressure switch-
min was selected.
The valve proving test can only be made via gas pressure switch-min, which must be
fitted between the valves. This has an impact on the control sequence (refer to chapter
Sequence diagrams). Valve proving is still activated via parameter 241.
7.5.2.3.

Lockout phase (phase 00)

The relays of the fuel valves and the safety relay (fan) are deenergized, 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.
Basic documentation LMV37.4...
7 Basic unit
Evacuation of test space (parameter 242)
Atmospheric pressure test (parameter 243)
Filling of test space (parameter 244)
Gas pressure test (parameter 245)
Fuel valve
Pressure switch-min
Pressure switch – valve proving
Input/output signal 1 (ON)
Input/output signal 0 (OFF)
Input permissible signal 1 (ON) or 0 (OFF)
CC1P7546en
20.09.2013