37
Multi Pass Oil Boilers
7 - BOILER SERVICING
Fig. 26
Cleaning the burner
7.4
Fig. 27 (70/90 & 90/140 RDB shown)
IMPORTANT: The electrode settings given above
MUST be observed
4 ± 0.3 mm
2 to 2.5 mm (50/70)
3 to 3.5 mm (70/90, 90/140)
Clamp screw
See Section 10
1
Combustion head - Loosen the two screws
securing the combustion head and withdraw the
head. Clean and replace the combustion head.
EOGB burner - To adjust the nozzle to
combustion head position (see Fig. 28), remove the
controls cover plate (see Fig. 25) and turn the
adjustment screw (4 mm allen key) anticlockwise
(towards -) increases the gap, turning the
adjustment screw clockwise (t) reduces
the gap. Replace the cover plate.
2
Inspect the ignition electrodes
Riello burner - Remove the combustion head.
EOGB burner - Detach the main burner assembly
by loosening the 4 mm socket headed bolt (see Fig.
29) and remove it from the front assembly.
Both burners - Loosen the electrode clamp screw
and withdraw the electrode assembly. Wipe clean
and check for any cracks in the ceramic insulation.
Replace if necessary.
Check the electrode settings
Riello burner - Electrode tips approximately 4 mm
apart and 2 to 2.5 mm (50/70) or 3 to 3.5 mm (70/90,
90/140) in front of the nozzle, see Fig 27.
EOGB burner - see Fig. 28.
3
Nozzle - Check that the nozzle size and type are
correct, refer to tables in Sections 2.2 or 2.3 and boiler
data label. Clean the nozzle with kerosene if necessary.
Do not use a pin or piece of wire to clean the nozzle.
Replace the nozzle if a build up of carbon is present.
With the combustion head removed (Riello burner)
or the burner assembly split (EOGB burner, see
paragraph 2 above), loosen the electrode assembly
clamp screw and slide the electrodes away from the
nozzle. Remove the nozzle using a good fitting
spanner (16 mm). The use of an ill-fitting spanner
will damage the nozzle and could lead to an
incorrect flame pattern. Always check the electrode
settings (and nozzle to combustion head position
for EOGB burner) after replacing the nozzle, see
Fig. 27 or 28.
