Fulton FB-S Horizontal Firetube Boiler - Manual (Page 41)

The Fulton Companies*FB-S Series Manual*Version 2010-0820 rev. 3/5/13
Page 41
i) Valve Proving System
i. A valve proving system, as show schematically below, is standard on the
FB-S Boilers. When the boiler operating sequence is initiated, the burner
control box energizes the proving system, which then carries out the
following checks.
a. Valves V1, V2 and V3 are initially closed. The proving
system then opens V3 and then closes it after 2 seconds.
b. V1, V2 and V3 remain closed for 23 seconds while the
minimum side of the gas pressure switch (PS) checks
for an increase in pressure. If no crease occurs there is
no leakage past V1 and the sequence continues.
c. V1 is opened for 2 seconds and then closed. V1, V2
and V3 again remain closed for 23 seconds while the
maximum side of the gas pressure switch checks for
a decrease in pressure. If no decrease occurs there is
no leakage past V2 or V3 and the burner operating
sequence will continue.
j) Flame Monitor
i. An ultraviolet cell is fitted as standard on all burners. It monitors the status
of the flame, any failure will cause the burner to shut down.