Hamworthy WESSEX-HE 200 Installation, Commissioning And Servicing Instructions page 33

Figure No. 7 - Sequence Controller Indicator Disc.
KEY: -
Position A: - Pre-Purge Starts
Approx. Time = 45 Seconds.
Position B: - Differential Pressure Proving
Switch Made - Red Line.
BLUE
Position C: - Ignition Circuit 'On'
and Pilot Gas valve open.
Position D: - Ignition Circuit 'Off'
Pilot Proving Period Starts.
Position E: - Main Gas Valve opens.
Position F: - Pilot Gas Valve
Closes.
Position G: - Burner Normal Run.
Position H: - Proving of
No Air Position.
Figure No. 8 - Burner Flow System Schematic (Natural Gas)
HAMWORTHY HEATING LTD
WHITE/BLUE
BLUE/YELLOW
YELLOW/RED
RED/YELLOW
YELLOW/GREEN
GREEN/WHITE
WHITE
27
WESSEX-HE 200 BOILER
KEY: -
I - Manual Gas Valve (Ball Type)
II - Control Gas Valve
III - By - Pass Gas valve
IV - Pilot Gas Valve
V - Pilot Burner
VI - Main Burner
VII - Differential Pressure Switch
VIII - Burner Fan
IX - Gas Orifice
X - Burner Insert
XI - Governor
XII - Air Swirler
500001008/K