45
15.3
BURNER INSPECTION
The heat exchanger has a sight glass for inspection of the flame picture.
NOTE: If the appliance has been in recent operation, this area may be hot. Appropriate precautions should
be taken to prevent personal injury.
To check the flame picture at high and low fire, the following procedure should be followed:
1.
Place the boiler into service mode. This is done by depressing the small button below the Enter/Reset
button for 5 seconds.
2.
The boiler should shut down and relight.
3.
Depress the service button momentarily, this should ramp the boiler up to full rate.
4.
Check the flame condition.
5.
Depress the service button momentarily, this should ramp the boiler down to low rate.
6.
Check the flame condition.
7.
Press and hold the service button for 5 seconds to take the unit out of service mode.
15.4
BURNER REMOVAL
If it has been determined that the flame picture is unacceptable, the burner can be removed and cleaned using the
following procedure:
1.
Isolate the electrical and gas supplies to the heater.
2.
Allow the boiler to cool down.
3.
Disconnect the wiring connections to the ignition electrode.
4.
Disconnect the power and control connection leads and earthing wire from the combustion fan.
5.
Apply a suitable release oil to the 6 studs around the edge of burner door.
6.
Remove the 6 retaining nuts around the edge of the burner door.
NOTE: Once loosened, the nuts should be removed by hand. If any of the nuts seize, the nut should gently
be re-tightened and additional release oil used.
7.
Withdraw the heat exchanger front plate and burner assembly from the heat exchanger complete with the
combustion fan.
8.
With the burner assembly away from the boiler, the burner can be gently cleaned with the brush attachment
of a vacuum cleaner.
The reassembly procedure is the reverse of the above taking care to ensure that the for the heat exchanger front
plate sealing gasket, the combustion fan connection gasket, the burner door insulation and the combustion chamber
rear wall insulation are in good condition or are replaced as necessary.
NOTE: PARTICULAR ATTENTION SHOULD BE PAID TO THE COMBUSTION CHAMBER REAR WALL
INSULATION. IF ANY DETERIORATION IN THE INSULATING MATERIAL IS NOTED, THE
INSULATION PANEL MUST BE REPLACED.
15.5
CLEANING THE HEAT EXCHANGER
To clean the heat exchanger, the following procedure should be carried out:
1.
Remove the burner as above.
2.
Use a vacuum cleaner to remove any accumulation on the heating surfaces. Do not use any solvent.
3.
Finish cleaning using a clean cloth dampened with warm water.
4.
Reinstall the burner.
5.
Close isolation valves on piping to isolate the appliance from the system. Attach a hose to the appliance
drain valve and flush the heat exchanger thoroughly with clean water by using purging valves to allow water
to flow through the water make-up line to the appliance.
6.
Once the heat exchanger has been flushed, close the drain valve and open the isolation valves.
7.
Restart the boiler as detailed in
Section 13.4.3:
PROCEDURE FOR INITIAL LIGHTING
.
