Sime DUETTO 20 OFi, Manual

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sembled in the following manner:
– Make sure that the boiler has been
emptied of water.
– Unscrew the union which connects
the expansion tank.
– Remove the expansion tank.
Before filling up the system make sure
that the expansion tank is reloaded at
the pressure of 0.8 ÷ 1 bar.
4.6 BURNER MAINTENANCE
To dismantle the burner from the boiler
door, remove the nut (fig. 15).
– To access the internal part of the
burner, remove the air lock unit
held in place by two screws to the
sides and remove the right hand
shell, which is held in place by four
screws, taking care not to damage
the O-ring seal. OR.
– To dismantle the nozzle holder and
heater unit, proceed as follows:
– open the cover, which is held in
place by a screw, and remove the
heater cables (1 fig. 15/a) pro-
tected by a heat resistant sheath;
remove the fairlead and pass the
cables through the hole.
– remove the two cables from the
ignition electrodes fastened in
place with a faston.
– loosen the union (2 fig. 15/a) and
remove the four screws which fas-
ten the collar (3 fig. 15/a) to the
burner.
– To dismantle the eater or thermo-
stat, refer to figure 15/b.
4.7 CLEANING
AND MAINTENANCE
Preventive maintenance and checking
of the efficient operation of the equip-
ment and safety devices must be car-
ried out at the end of each heating
season exclusively by the authorised
technical staff.
4.7.1 Cleaning smoke ducts
Use an adequate swab for cleaning
the smoke ducts of the boiler. After
cleaning, position the circulators in
their original position (fig. 16).
4.7.2 Cleaning combustion head
The combustion head is cleaned in the
following manner (fig. 17):
80
4
5
2
6
3
1
Fig. 14
Fig. 15
2 1
3
Fig. 15/a
KEY
1 Control bow cables
2 Connection
3 Collar