15.4.1 Gas Valve
Do not remove the inner casing.
Unscrew the fixing screw and unplug the connections.
Remove the air pressure switch. refer to section 15.4.19.
Unscrew the union connections above and below the gas valve,
unscrew the mounting bracket and remove the assembly. Use
new gaskets when replacing the valve. Refer to Fig. 43.
Set the Gas Valve:
Connect a pressure gauge to the burner pressure test point on
the valve. Refer to Fig. 39.
Switch on the gas and electricity supplies. Check for gas
soundness at the gas valve inlet.
Refer to Section12-Commissioning for the method of checking
the pressures.
Check for gas soundness at the gas valve outlet.
Adjust the gas valve to obtain the required pressure.
Switch off the appliance, disconnect the pressure gauge and
tighten the test point screw. Refer to Fig. 43.
15.4.2 Spark Electrode
Remove the inner casing and the combustion chamber.
Lower the facia
Carefully pull off the leads at the electrodes. Loosen the screw
and remove the electrode assembly. Refer to Fig .44.
15.4.3 Flame Sense Electrode
Remove the inner casing and the combustion chamber.
Lower the f`acia.
Separate the in-line connector located in the controls
compartment. Remove the burner. Refer to Section 15.4.4.
Loosen the screw and remove the electrode assembly. Refer to
Fig.44. Ensure that the new electrode is at the correct height
above the burner blade.
15.4.4 Burner
Remove the inner casing and the combustion chamber.
Separate the flame sense electrode in-line connector located in
the controls compartment.
Release the union connection beneath the burner and remove
the burner from the appliance. Refer to Fig. 43 and 44.
Do not omit the gasket when fitting the new burner.
24
Fig.44 . Burner and Electrode
3-4mm
5-6mm
5-6mm
Spark
electrode
assembly
Spark electrode
detail
Flame
sensor
position
Flame sensor
detail
Burner injector
Burner
Burner
fixing nut
Fig.43 . Lower Casing - Gas and Water
Controls.
1
2
1
3
5
4
6
1. Pump
2. Flow manifold
3. Filling Loop
4. Air pressure switch
5. Gas Valve
6. Pressure relief valve
7. Connector
8. Bypass
