281 Issue 1 - Service Manual - BX3
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7.0 DISMANTLING PROCEDURES
Before any of the following assemblies or components can be removed, it is important to isolate
the heater’s power supply.
The lid of the heater will also have to be removed by removing 2 screws at each end of the lid.
7.1 Burner Assembly Removal
1. Turn the gas isolation valve off and isolate the heater’s power supply
2. Unscrew the hose clamp off the combustion fan flue pipe. Remove the flue cowl off the
front of the unit and slide the flue pipe out of the unit.
3. Remove the gas valve loom; spark igniter lead, flame sensor lead and flame rollout switch
loom and plate.
4. Remove the gas inlet pipe off the gas valve and move the piping enough to enable the
burner assembly to be removed when ready.
5. Remove the 2 screws that hold the flame rollout switch plate then remove the plate away
from the gas manifold.
6. Remove the other 2 screws holding the burner manifold to the burner assembly and
remove the assembly.
7. Remove the 4 screws holding the burner assembly to the heat exchanger main plate.
8. The burner assembly can now be removed.
Installation is a reversal of the removal procedure with attention to the following points:
1 Ensure that the gas inlet feed-tube is retightened and checked for leaks.
2 Ensure that all looms, wires and leads are not damaged along their length and at the
connectors.
7.2 Gas Manifold Assembly Removal
1. Turn the gas isolation valve off and isolate the heater’s power supply.
2. Unscrew the hose clamp off the combustion fan flue pipe. Remove the flue cowl off the
front of the unit and slide the flue pipe out of the unit.
3. Remove the gas valve loom from the gas valve.
4. Remove the gas inlet feed-tube off the gas valve.
5. Remove the 2 screws that hold the flame rollout switch plate then remove the plate away
from the gas manifold.
6. Remove the 2 screws holding the gas manifold to the burner assembly.
7. The gas manifold assembly can now be removed.
Installation is a reversal of the removal procedure with attention to the following points:
1. When re-inserting the assembly, ensure that the injectors are inserted into the ring on the
top of the burners correctly.
Ensure that the gas inlet feed-tube is retightened and checked for leaks.
2. Ensure that the gas valve loom is not damaged along its length and at the connector.
