FCU 500, FCU 505 · Edition 02.17
109
Parameters
12 .5 .3 Tightness control test volume
Parameter 53
Parameter 53 is used to define whether one or two test
volumes are checked for tightness and whether a safety
valve or a relief valve is used for reducing the pressure.
Parameter 53 = 1: V
p1
.
A test volume (V
p1
) between two safety valves (V1, V2)
is checked for tightness.
V2
pu
Vp1
V1
PZ
pu
2
Parameter 53 = 2: V
p1
; pressure reduction via V3.
The system tightness is checked with one test volume (V
p1
)
between two safety valves. The relief valve V3 is opened to re-
duce the pressure in the test volume by venting to a safe area.
V1
PZ
Vp1
pu
pu
2
V3
Parameter 53 = 3: V
p1
+ V
p2
; pressure reduction via V3.
The system tightness is checked with two test volumes
V
p1
and V
p2
. During the tightness test of V
p1
, almost at-
mospheric pressure must prevail in the test volume V
p2
.
Relief valve V3 is opened to reduce the pressure in test
volume V
p2
. Pressure switch DG
V3
is used for the con-
trolled pressure reduction of test volume V
p2
. For the
circuit design, see page 130 (System leak tightness
check).
The time and the duration of the pressure reduction
of the test volume can be adjusted using parameters
54 and 55 for checking the system tightness, see
page 110.
V3
DG
V3
pu
Vp1
PZ
pu
2
V1
V2
PZ
Vp2