Honeywell BCU 465 - Valve Proving System; Tightness Control

BCU 460, BCU 465 · Edition 11.19 40
Valve proving system
6 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 page40 (Tightness control).
6.1 Tightness control
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
p
u
V
p1
V1
PZ
p
u
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 (Valve proving systems for automat-
ic shut-off valves for gas burners and gas appliances).