Main Heating Main Heat 12, Installation & Service Manual

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Fig. 39
Fig. 40 & Fig. 41
page 44
11. To clean the heat exchanger and burner proceed as follows:
a. Disconnect the electrical leads to the fan component protection sensor ( Fig. 42 ).
b. Loosen the screw retaining the gas injector pipe at the venturi ( Fig. 42 ).
c. Undo the two wing nuts to disconnect the fan ( Fig. 42 ).
d. Remove the fan and disconnect the electrical supply to it ( Fig. 42 ).
e. Remove the gas injector pipe from the gas valve (push-fit) ( Fig. 42 ).
f. Undo the condensate trap securing nut, lock nut and the condensate drain pipe. Remove the condensate trap and disconnect the sensor leads ( Fig.
43 ).
g. Remove the two screws securing the burner and remove the burner. Visually inspect the internal burner baffle for obstruction, check seal around baffle
for cracks/damage. Clean with a soft brush.
h. Loosen the two screws retaining the heat exchanger support bracket and slide to the left to remove( Fig. 44 ).
i. Remove the four screws securing the heat exchanger/combustion box base and withdraw the base.
j. Lower the central insulation panel and check condition (
Fig. 44 ). Replace the lower insulation pad if necessary.
k. Ensure the heat exchanger fins are clear of any obstruction.
l. Check condition of all seals. Important: Pay particular attention to the condition of the combustion box door seals.