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TC · Edition 08.17
17
Application
1 .1 .11 TC 4 in a multiple burner system with several valves
installed in series
V1 and V2: quick or slow opening valves with start rate.
Tightness control TC 4 checks the central shut-off valve
V1, the gas solenoid valve V2 and the pipe between
these valves for tightness.
Valve V2 can only be checked for tightness when the
pressure downstream of V2 approximately corresponds
to the atmospheric pressure. The gas solenoid valve
VAS and the pressure switch DG
VAS
are used to relieve
the pressure. The pressure switch must be adjusted in
such a way so that enough pressure is relieved and no
air can get into the pipework.
After the thermostat/start-up signal
ϑ
has been applied,
first DG
VAS
is checked. If the pressure downstream of
V2 is correct, the VAS closes and the tightness test is
started.
Once the tightness test has been carried out success-
fully, TC 4 opens the main valves V1 and V2 with the
OK enable signal and enables the downstream burner
control units.
p
u
2
OK
L1(+)
N(-)
TC 4
K1
k1
VAS
1 2 3 4 5 6 7 8 9 10 11 12 13
DG
VAS
k1
V1
V2
p
u
TC 4
V1
V2
VA
S
PZ
DG
VA
S
p
z
V
P
PZ
PZ
DG