Honeywell Krom Schroder BCU 580, Техническая информация, Страница: 33 / 131

BCU 580 · Edition 11.15l 33
Valve proving system
5 .1 .3 Test period t
P
Depending on the burner capacity, the tightness of the
gas solenoid valves must be checked in accordance
with the relevant application standard, e.g. EN 676,
EN 746, NFPA 85 and NFPA 86.
BCU 560..C1
µC
P
13 14
45
47 58 48
p
u
/2
TC
PZ
PZL PDZ
M
>750°
ϑ
1
2
3
p
u
/2
PZ
V
p1
V1 V2
p
u
p
z
p
d
The test period t
P
is calculated from:
– Opening times t
L
for V1 and V2,
– Measurement times t
M
for V1 and V2.
t
P
[s] = 2 x t
L
+ 2 x t
M
5 .1 .4 Opening time t
L
Standard EN 1643:2000 allows a maximum opening
time of 3 s for the tightness test if the main gas valves
are actuated directly. If gas can flow into the combus-
tion chamber when a valve is opened, the gas volume
must not exceed 0.083 % of the maximum flow rate.
5 .1 .5 Measurement time t
M
The sensitivity of the tightness control in the BCU can
be adjusted for each individual system by adapting the
measurement time t
M
. The longer the measurement
time t
M
, the greater the sensitivity of the tightness con-
trol. The measurement time is set using parameter 56
to a value between 3 and 3600 s – see page 96
(Measurement time V
p1
).
The required measurement time t
M
is calculated from:
Inlet pressure p
u
[mbar]
Leakage rate Q
L
[l/h]
Test volume V
p1
[l]
Calculation of the test volume, see page 34 (Test volume V
p1
)
For one test volume V
p1
between 2 gas solenoid
valves
Adjustable using parameter 56
t
M
[s] =
(
2 x p
u
x Vp1
)
QL
For a large test volume V
p1
with reduced testing
time
Adjustable using parameter 56
t
M
[s] =
(
0.9 x p
u
x V
p1
)
Q
L
Conversion into US units, see page 124 (Converting
units)
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