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TC · Edition 08.17
10
Application
1 .1 .4 TC 2 with two gas solenoid valves and one auxiliary
valve for discharge
Mains voltage = control voltage
V1 and V2: quick or slow opening valves with start rate.
V3: quick or slow opening valve with start rate, nominal
size is dependent on test volume V
P
and inlet pres-
sure p
u
, see page 38 (Project planning information),
but is at least DN 15.
TC 2 checks gas solenoid valves V1, V2, the auxiliary
valve V3 and the pipe between the valves for tightness.
It must be ensured that the interspace p
z
is vented dur-
ing the 3-second opening time. This is not guaranteed
by the gas pressure regulator downstream of V2. A relief
line is thus used to discharge the test volume V
P
safely
into the combustion chamber or into a safe area. Auxil-
iary valve V3 can also be used as a pilot gas valve. Since
valve V2 remains closed during the test, it can also be a
slow opening motorized valve VK.
Once the tightness test has been carried out success-
fully, the tightness control forwards the OK enable sig-
nal to the automatic burner control unit GFA. The GFA
opens the gas solenoid valves V1 and V2 simultane-
ously. The burner starts.
GFA
V1
p
u
2
V1
V2
PZ
p
u
p
z
TC 2
V3
V
P
TC 2
OK
V2
9
V3