Test Instant - Honeywell Krom Schroder BCU 580 Technical Information

Valve proving system

5 .1 .1 Test instant

Depending on the parameter setting, the tightness
control checks the tightness of the pipework and the
gas solenoid valves before each start-up and/or after
each shut-down of the burner, see page 95 (Valve
proving system).
The gas line is always safeguarded by a gas solenoid
valve during this check.
Before burner start-up
The valve check is started when the start-up signal ϑ1
is present at terminal 1. The BCU checks the tightness
of the gas solenoid valves and the pipework between
the valves. The gas line is always safeguarded by a gas
solenoid valve during this check. The pilot burner is ig-
nited when pre-purge is ended and the tightness has
been checked successfully.
After burner shut-down
After the burner has been shut down, the BCU checks
the tightness of the gas solenoid valves and the pipe-
work between them. Once the test has been carried out
successfully, the next burner start is enabled.
The BCU always conducts a tightness test if mains volt-
age is available or if it is reset after a fault lock-out.
An additional bypass/relief valve must be installed in
gas sections with an air/gas ratio control. This ensures
that the test volume V
p1
ness test with the air/gas ratio control closed.
BCU 580 · Edition 11.15l
can be vented during the tight-
PZH
VAS VAG
V
p1
V1 V2
V4
p /2
u
45 13 14 57
BCU 580..C0F3
V3
VAS 1
µC
V1
V2
PZH
VAS VAG
V
p1
p /2
u
45 13 14 15 57
BCU 580..C0F3
µC
VAS 1
V4
VAS 1
30