Strebel S-CB Px 120, Installation Operating & Maintenance Manual

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S-CB Px 120 Manual 101
Service history
The operational and fault history (total amount and since the last service) of the boiler can be retrieved with the
help of a computer, correct software and an interface cable. This information can be used to specify the mainte-
nance and service proceedings in relation to the boiler (parts).
Water leakage
The water pressure of the heating installation should be more than 1.0 bar and at a maximum of 4.0 bar. When
the water pressure drops below the minimum occasionally, there might be a water leak. Check the boiler and the
complete heating installation for any water leakages and have these repaired.
Flue gas & air supply
The flue gas and air supply pipes must be checked for gas tightness. Also check if the mounting of these pipes is
correct, safe and not damaged. Check the top panel of the boiler housing for signs of water leakage and traces of
water coming from the air supply pipe, the air vent or any condensate coming from the flue gas pipes.
The flue gas outlet has been provided with a flexible adaptive restriction, which should be checked an-
nually. If necessary, remove contamination or other possible failure causes. If there is any doubt of the
good state or correct functioning of the adaptive restriction, it must be replaced.
Gas supply & safeties
The gas pipes must be checked for gas tightness. Also check if the mounting of these pipes is correct. safe and
not damaged. Any built in safeties should be checked for a correct functioning.
Remove complete burner unit
The complete burner unit consists of the fan, the burner plate and the internal burner.
To remove this part, loosen and remove the six nuts on the burner door and disconnect the ignition cable and
ground wire connector. When the inlet venturi and the cables connected to the fan are disconnected, one can pull
the burner door assembly outwards about 5-6 cm.
While keeping the burner in the heat exchanger one can turn the whole unit clockwise until the black fan motor
cover touches the foam on the inside of the left side panel.
Gently press the black fan cover in the foam, creating just enough clearance for the bottom of the fan housing to
slide just over the connection terminals.
If this clearance is ensured, one can pull the whole burner door assembly outwards and thereby remove it from
the boiler.
NOTICE: To make removal more easy, one can loosen and remove the three mounting screws in the bottom half
of the left panel. Two screws are situated on the bottom of the boiler, on the ridge of the left side panel,
and one is situated in the display console in front, at the front ridge of the left side panel. After this one
can bend the bottom of the left side panel outwards while the panel is still fixed with the two side panel
mounting screws on top. This will create more clearance for the removal of the burner door assembly.
NOTICE: When handling the burner door assembly during removal, mounting and maintenance, be sure that the
insulation of the burner door is not damaged.
Burner
Check the burner surface to see if it has damages. signs of rust and/or is cracked. When the burner surface is
damaged the burner must be replaced. The burner can be cleaned by using a soft (non-metallic) brush. The dust
can be removed with a vacuum cleaner or pressurized air.
Ignition / ionisation electrode
When the complete burner is removed, it is very easy to check the ignition electrode. First check if the distances
between the electrodes and between the electrode and the burner are according to the graph below. When these
are not correct, try to bend the electrodes in the right position. Notice: the electrodes undergo high temperatures,
therefore the electrodes become hard and are difficult to bend. While bending used electrodes they might break or
burst. Check the electrode, after bending, for any tear/crack and signs of rust. When they are burst/cracked or
rusty, replace the electrode. Also replace the electrode when there is a crack in the ceramic insulation of the elec-
trode. When the electrode is going to be replaced also the gasket should be renewed.