BCU 460, BCU 465 · Edition 11.19
100
Parameters
11 .9 Valve check
11 .9 .1 Valve proving system
Parameter A051
Parameter A051 is used to define whether and at what
time in the BCU program sequence the valve check is
activated. This allows either the tightness of the gas
solenoid valves and the pipework between them to be
checked (tightness test) or the closed position of a so-
lenoid valve (proof of closure function) to be checked.
If the proof of closure function is activated, the closed
position of a gas solenoid valve is checked using a POC
switch.
Parameter A051 = 0: Off. No valve check is activated.
Parameter A051 = 1: tightness test before start-up.
Parameter A051 = 2: tightness test after shut-down.
With this setting, a tightness test is also performed af-
ter a fault is reset and after mains on.
Parameter A051 = 3: tightness test before start-up and
after shut-down.
An additional bypass valve must be installed in gas sec-
tions with an air/gas ratio control. This valve allows the
closed air/gas ratio control to be bypassed during the
tightness test.
11 .9 .2 Relief valve (VPS)
Parameter A052
A valve connected to terminal 61 or 62 can be selected
to act as a relief valve during a tightness test.
PZH
BCU 460..C1F1
µC
VAS
V1
V2
V3
p
u
/2
61 62
61
38
5
ϑ
1
35
2
81
82
95
96
V
p1
V3
V2
61 62
V3
V2
Parameter A052 = 2: V2. The valve on terminal 61 acts
as the relief valve.
Parameter A052 = 3: V3. The valve on terminal 62 acts
as the relief valve.