Potterton PRIMA 30C User Manual page 25

SERVICING INSTRUCTIONS - Page 25
g Remove the split pin retaining the thermostat bulb and
withdraw bulb from its pocket.
h Remove split grommet in the base of the boiler and the
split grommet from the side of the control box, and feed
thermostat capillary and bulb through holes.
I Replacement is the reverse of removal. The bulb of the
new thermostat should be coated with heat conducting
paste. Ensure the split grommet in the base of the boiler
makes a good seal around the capillary.
j Ensure that the capillary is secure in the clips provided.
Follow the full commissioning procedure as detailed in
the COMMISSIONING section of these instructions.
SPILLAGE DETECTOR THERMOSTAT
a Carry out operation A,B,C,D,E in section 1
PREPAIRING BOILER FOR SERVICE.
b Remove the sensor from the support clips in the down
draught diverter and carefully remove the capillary from
the support clips on the front edge of the casing.
c Carefully dislodge the split grommet from the base of the
boiler and feed the capillary and bulb through the hole.
d Access to the spillage detector thermostat contacts is
carried out by separating the thermostat housing from
the control box see Fig 22. This is done by removing the
securing screw (identified in Fig 18a) and lowering the
housing.
e Remove the two leads from the S.D.T. (Polarity is not
important).
f Remove the thermostat fixing nut then remove the
thermostat complete with its capillary and two split
grommets from the control box slots
g Replacement is the reverse of removal, fit the two split
grommets to the new thermostat capillary, carefully bend
the new capillary to match the contour of the
disconnected one.
h Ensure that the capillary is routed away from hot metallic
surfaces (see Fig 18a) and the sensor bulb is located
centrally between the two locating clips. Also ensure that
the location pin of the thermostat is properly located
before tightening the locking nut.
i Make sure the split grommet in the base of the boiler
makes a good seal around the capillary.
j Follow the full commissioning procedure as detailed in
the COMMISSIONING section of these instructions
OVERHEAT THERMOSTAT
a Carry out operations A,B,C,D in section 1
PREPARING BOILER FOR SERVICE.
b Remove control box securing screw and lower control
box.
c Access to the overheat thermostat is made easier by
separating the upper assembly of the control box from
the boiler base. This is done by removing the two
hexagonal head screws identified in Fig.21. Tilt the
upper assembly and disconnect the two push-on
electrical connections from the overheat thermostat
terminals.
d Remove the nut securing the thermostat to the control
box.
e Remove clip securing the thermostat bulb to the pipe.
f Remove split grommet in the base of the boiler and the
split grommet from the side of the control box and feed
thermostat capillary and bulb through holes.
g Replacement is the reverse of removal. The bulb of the
new thermostat should be coated with heat conducting
paste. Ensure the split grommet in the base of the boiler
makes a good seal around the capillary.
h Ensure that the capillary is secure in the clips provided.
Follow the full commissioning procedure as detailed in
the COMMISSIONING section of these instructions.
Figure 22
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