andrews COMBIflo 100/300 Installation, Operation And Maintenance Manual page 61

Changing the heat exchanger will require draining of the primary system. It is essential that all the
air is removed from the heat exchanger before the appliance is operated. To not do so may damage the
heat exchanger and invalidate the warranty.
6.2.14 HEAT EXCHANGER
• Drain as much of the primary water as is necessary to ensure the heat exchanger is empty.
• Disconnect all electrical connections to the fl ue sensor, spark generator, fan and gas valve.
• Disconnect the air tube and air control fl ap (see 6.2.11 for details)
• Release both the heat exchanger demountable connections of the fl ow and return pipes, by removing the metal
clips and pulling the pipes downwards.
• Disconnect the condense drain connection by releasing the plastic clip on the top connector.
Gas valve screws (x3)
• Disconnect the gas valve from the venturi by removing the three securing screws
Heat exchanger door screws
• Remove the whole burner system using the four retaining nuts holding the heat exchanger door to the body.
ANDREWS COMBIfl o DRAFT
Condense
drain clip
Flow / Return Clips
59 GB/IE