281 Issue 1 - Service Manual - BX3
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7.3 Gas Valve Removal
1. Turn the gas isolation valve off and isolate heater’s power supply
2. Disconnect the gas valve loom.
3. Remove the gas inlet feed-tube off the gas valve.
4. Remove the gas valve from the burner manifold by unwinding it in an anti-clockwise
direction.
4. Remove the brass adaptor on the gas valve inlet side of the gas valve if the valve is to be
replaced.
Installation is a reversal of the removal procedure with attention to the following points:
•
Clean any threads of excessive gas thread sealant, which are to be re-assembled
•
If a new gas valve is to be fitted, apply gas thread sealant to the brass adaptor and finger-
tighten onto the gas valve.
•
Apply gas thread sealant to the burner manifold feed tube nipple and screw on the gas
valve, and then tighten.
•
Check for leaks on both sides of the gas valve while in operation.
•
If a new gas valve is fitted, ensure that it is reset, including the gas pressure, as outlined in
the technical information sheet regarding the unit pressures.
7.4 Pressure Switch Assembly Removal
1. Isolate the heater’s power supply.
2. Remove the hose from the pressure switch.
3. Remove the electrical wires from the pressure switch.
4. Remove the pressure switch fastening screw if the pressure switch is to be replaced.
Installation is a reversal of the removal procedure with attention to the following points:
•
Ensure all wiring connections are positively located and that no looms have been
damaged.
•
Ensure the pressure hose is connected as far as possible to the body of the pressure
switch nipple.
7.5 Combustion Fan Removal
Method 1 – Partial fan removal
1. Isolate the heater’s power supply.
2. Remove the electrical leads off the combustion fan.
3. Remove the flue cowl off the flue pipe that is on the external wall of the heater
4. Unscrew the hose clamp that holds the flue pipe onto the combustion fan outlet.
5. Remove the flue pipe and rubber silicone connector.
6. Remove 3 screws which fasten the combustion fan down to the combustion fan box.
7. Pry the combustion fan off the box, which will still be fastened by the sealing heat proof
silicon.
Installation is a reversal of the removal procedure with attention to the following points:
1. Clean both surfaces to be re-mated together.
Apply sufficient (but not excessive) silicon to the combustion fan’s mating surface
