Fulton Boiler FBS Series
17 FBS 01/05
4) Valve Proving System.
A valve proving system, as show schematically below, is standard on the
boilers from FB-S3-1.0 to FB-S6-1.25 model.
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.
5) Flame Monitor.
An ultraviolet cell is fitted as standard on all burners. It monitors the status of the
flame, any failure will course the burner shut down.
