Replacement Of Central Heating Expansion Vessel - Vaillant ecoMAX 635 Instructions For Installation And Servicing

• Remove 2 screws (3) securing gas valve to fan.
• Disconnect gas inlet supply connection from gas valve
by removing four screws. Refit the gas inlet supply
connection to the new gas valve using the new sealing
gasket supplied.
• Fit new gas valve to fan using the new sealing gasket
supplied.
• Refit gas valve and fan assembly to burner manifold
using the new sealing gasket supplied. Equally tighten
the four screws (1) to ensure a good seal is made.
• Reassemble burner, gas valve and fan assembly in
reverse order.
• Recommission boiler as previously detailed. Ensure
combustion analysis is carried out after part replace-
ment as detailed in section 9.8.
Fig. 9.2 Replacing the gas valve
3
Fig. 9.3 Gas valve
Instructions for installation and servicing ecoMAX

9.5 Replacement of central heating expansion vessel

• Turn off boiler.
• Remove front casing.
• Lower control box.
• Drain boiler as previously described.
• Disconnect union (1) from expansion vessel (4).
• Remove two screws (2) and remove retaining bracket (3).
• Slide the expansion vessel forward to remove from the
boiler.
• Reassemble in reverse order.
• Recommission boiler as previously detailed.
2
1
1
Fig. 9.4 Replacing the expansion tank
Parts replacement 9
2
2
3
4
1
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