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BCU 580 · Edition 11.15l
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Valve proving system
5 Valve proving system
The BCU 500..C1 is fitted with an integrated valve prov-
ing system. 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.
Once the test has been carried out successfully, the
burner enable signal is issued.
For details, see following chapter Tightness test and
page 36 (Proof of closure function)
5 .1 Tightness test
The aim of the tightness control is to identify an inad-
missible leak on one of the gas solenoid valves and to
prevent burner start. Gas solenoid valves V1 and V2 are
tested as is the pipework between the valves.
V2
pu
Vp1
V1
PZ
pu
2
European standards EN 746-2 and EN 676 stipulate
tightness controls for capacities over 1200 kW (NFPA
86: from 117 kW or 400,000 Btu/h).
The tightness control function satisfies the require-
ments of EN 1643, EN 746-2, ISO 13577-2 and NF-
PA 86 for valve proving systems.