Glow-worm Xtramax - Manual (Page 39)

39
4000116705-2
Diagram 20.12
9126
➜
20 Replacement of Parts
20.16 Gas safety valve, refer to diagram 20.11.
Before starting refer to the front of Section 20 Important
information.
• Remove the front panel, refer to Section 17.3.
• Lower the control panel, refer to Section 17.5.
• Remove the gas control valve assembly, refer to Section
20.15.
• Locate gas safety valve on the rear of the gas control valve.
• Unscrew and remove the 2 screws securing the gas safety
valve to the gas control valve.
• Fit replacement gas safety valve taking care not to damage the
'O' ring.
• Refit gas control valve assembly into boiler.
20.17 Spark ignition unit, refer to diagram
20.11.
Before starting refer to the front of Section 20 Important
information.
• Remove the front panel, refer to Section 17.3.
• Lower the control panel, refer to Section 17.5.
• Disconnect electrical connections from spark ignition unit.
• Remove screw securing spark ignition unit to gas control valve
mounting bracket.
• Fit replacement spark ignition unit.
20.18 Central heating safety valve
Before starting refer to the front of Section 20 Important
information.
• Remove the front panel, refer to Section 17.3.
• Lower the control panel, refer to Section 17.5.
If safety valve seating is damaged, it will be necessary to
replace safety valve as a complete unit, repair is not possible.
Drain down central heating water circuit of the boiler only, see
diagram 20.1.
• Disconnect safety valve discharge pipe from safety valve.
• Remove wire clip securing safety valve to fixing jig and remove
safety valve, see diagram 20.12.
• Fit replacement safety valve.
Note: Apply a small quantity of silicon grease to the safety valve
'O' ring prior to fitting.
20.19 Main heat exchanger
Before starting refer to the front of Section 20 Important
information.
• Remove the front panel, refer to Section 17.3.
• Remove the sealed chamber cover, refer to Section 17.4.
• Lower the control panel, refer to Section 17.5.
• Remove the combustion chamber cover, refer to Section
17.7.
• Drain down central heating water circuit of the boiler, see
diagram 20.1.
• Release flue hood as follows:
From front of boiler carefully unclip wire spring retainers from
side of flue hood.
• Undo nut securing pipe from heat exchanger to 3-way valve/
bypass housing.
• Whilst supporting heat exchanger, undo nut securing pipe
from heat exchanger to central heating pump.
• Slide heat exchanger forwards and remove from boiler taking
care not to damage insulation.
DO NOT DAMAGE PAINTED FINISH OF HEAT EXCHANGER
• Fit replacement heat exchanger.
Note: Locate heat exchanger into slot at rear of combustion
chamber.
20.20 Central heating expansion vessel
Before starting refer to the front of Section 20 Important
information.
• Remove the front panel, refer to Section 17.3.
• Lower the control panel, refer to Section 17.5.
Drain down central heating water circuit of the boiler, see
diagram 20.1.
Undo pipe coupling on expansion vessel.
Unscrew and remove expansion vessel retaining nut.
Supporting expansion vessel, unscrew and remove screws
securing expansion vessel bracket to boiler.
Lift expansion vessel out of boiler.
Fit replacement expansion vessel.
Note: Check that expansion vessel pressure is correct, see
‘Section 1 Technical Data’.