Kromschroder FCU 500 - Two Test Volumes for System Tightness

FCU 500, FCU 505 · Edition 02.17 42
Valve proving system
7.1.4 Two test volumes for system tightness
P
Z
L
P
Z
H
FCU 500..C1
µC
P
4
9
1
5
13
1
450
47
58
48
T
C
PZL PD
Z
M
>750°
ϑ
1
2
3
p
u
/2
PZ
V
p1
V
p2
V1 V2
45
V3
p
u
p
Z
The test volumes V
p1
and V
p2
(gas solenoid valves V1
and V2, relief valve V3, the burner valves and the pipe-
work) are checked to test the system tightness of the
entire gas inlet section.
Program sequence
At the start of the tightness test, the relief valve V3 is
opened to reduce the pressure of the test volume V
p2
to around atmospheric pressure. The opening time for
V3 can be defined using parameter 55, see page 110
(Opening time relief valve V3). The tightness con-
trol queries the pressure p
Z
using the external pres-
sure switch to check the first test volume. If pressure
p
Z
> p
u
/2, program A starts, see page 43 (Program A).
If pressure p
Z
< p
u
/2, program B starts, see page 44
(Program B).
t
L
= P59
t
M
= P56
+
–
t
L
= P59
t
M
= P56
p
Z
>
p
u
2
+
–
V2
OK
p
Z
>
p
u
2
V1
OK
V1
V2
OK
V1
V1
V1
OK
V2
V2
V2
V1
V2
p
Z
>
p
u
2
+
–
p
Z
>
p
u
2
+
–
t
L
= P59
t
M
= P56
V1
V1
t
L
= P59
t
M
= P56
V2
V2
p
Z
>
p
u
2
+
–
t
L3
= P55
V3
V
p2
OK
V
p1
OK
p
Z
>
p
u
2
+
–
t
L
= P59
t
M
= P57
V1
V2V3
V1
V
p2
Program A Program B
Program A Program B
Vent V
p2
Test of valve 1
V
p1
Test of valve 2
V
p1
Test of valve V3
and
burner-side
valves
V
p1
+ V
p2
Wait for 1 s
END
START
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