Replacement Of Parts; Control Thermostat; Over Heat Cutoff Device - Saunier Duval Xeon 50ff Instructions For Use Installation And Servicing

Note. Replacement of parts must only be carried out by a
competent person.
Before replacing any parts isolate the boiler from the electrical
supply and turn the gas supply off at the gas service cock,
indicator slot to be vertical.
Unless stated otherwise, all parts are replaced in the reverse
order to removal.
After replacing any parts always test for gas soundness and if
necessary carryout functional check of controls.
10.1 Access
Gain Access as Section 8.1.
10.2 Control Thermostat - diagram 10.1 and
10.2
Remove and support the electrical control box, refer to Section
5.6.
Remove the control knob. Remove the electrical connections
from the thermostat body.
Release the thermostat body by unscrewing the two screws and
shakeproof washers in the front of the control box.
Remove the split pin and withdraw the thermostat phial from its
pocket. Release the capillary from the base and plastic retaining
clip then remove it from the split grommet.
Release the capillary from its clips.
Remove the thermostat complete from the boiler.
Re-assembly note. When fitting the thermostat, make sure that
the thermostat phial is covered with heat sink compound and
then fully inserted into the phial pocket and that the capillary is
within the gland seal, see diagram 10.2. Remake the electrical
connections.
There must be no kinks or sharp bends in the capillary.
10.3 Over Heat Cutoff Device - diagram 10.1,
10.2 and 10.2A.
Release the control box as Section 5.6.
Remove the overheat cutoff electrical connections.
Disconnect the air pressure switch plug from the PCB.
Remove the locking nut from the overheat cutoff.
Release the capillary from the retaining clips then remove it
from the split grommet.
Slacken the bracket and remove the phial from the pipe.
When refitting use the heat sink compound provided and make
sure that the phial is correctly fitted into the groove on the pipe.

10 Replacement of Parts

SHAKEPROOF
WASHERS AND
SCREWS
33
CONTROL
THERMOSTAT
CONTROL
KNOB
LOCKNUT
ELECTRICAL
CONNECTIONS
ELECTRICAL
CONNECTIONS
YELLOW 2 & 3
SPLIT
GROMMET
RETAINING
CLIP
Diagram 10.1
221658B