18.4.6 Removing the fan 1. Carry out step 18.2.1; 2. Remove the air gas manifiold as in 18.4.2 (Fig. 18.36); 3. Unscrew the two screws from the venturi “J” and remove with the gas valve (Fig. 18.37); 4. Unscrew the three screws “K” on the air/gas pipe and remove (Fig. 18.38); 5. Reassemble in reverse order. J K Fig. 18.36 Fig. 18.37 Fig. 18.38 18.4.7 Removing the gas valve 1. Carry out step 18.2.1; 2. Remove the air gas manifiold as in 18.4.2 (Fig. 18.39); 3. Unscrew the three screws “L” on the air/gas pipe and remove (Fig. 18.40); 4. Unscrew the three screws holding the gas valve on the venturi (Fig. 18.41); L Fig. 18.39 Fig. 18.40 Fig. 18.41 5. Remove the gas valve from the venturi. (Fig. 18.42); 6. Reassemble in reverse order; 7. The gas valve settings will need to be adjusted (see Section 14.3 page 28); 8. Reinstate the gas supply and test for tightness on reassembly. Fig. 18.42 52
18.4.8 Removing the heat exchanger 1. Carry out step 18.2.1; 2. Remove the air gas manifiold as in step 18.4.2 (Fig. 18.43); 3. Unscrew the three bolts “M” from the main heat exchanger (Fig. 18.44); 4. Remove the flow and return pipes and the condense drain pipe from the heat exchanger. (Fig. 18.45); M Fig. 18.43 Fig. 18.44 Fig. 18.45 5. Remove the heat exchanger from the boiler by sliding out. (Fig. 18.46); 6. Reassemble in reverse order. Fig. 18.46 18.4.9 Removing the spark generator 1. Carry out step 18.2.1; 2. Disconnect the earth cable from the ignition electrode. (Fig. 18.47); 3. Disconnect the ignition electrode, live, neutral and earth cables from the ignitor. (Fig. 18.48); 4. Remove the two screws “N” from the ignitor and remove (Fig. 18.49); 5. Reassemble in reverse order. N Fig. 18.47 Fig. 18.48 Fig. 18.49 53
18.4.6 Removing the fan 1. Carry out step 18.2.1; 2. Remove the air gas manifiold as in 18.4.2 (Fig. 18.36); 3. Unscrew the two screws from the venturi “J” and remove with the gas valve (Fig. 18.37); 4. Unscrew the three screws “K” on the air/gas pipe and remove (Fig. 18.38); 5. Reassemble in reverse order. J K Fig. 18.36 Fig. 18.37 Fig. 18.38 18.4.7 Removing the gas valve 1. Carry out step 18.2.1; 2. Remove the air gas manifiold as in 18.4.2 (Fig. 18.39); 3. Unscrew the three screws “L” on the air/gas pipe and remove (Fig. 18.40); 4. Unscrew the three screws holding the gas valve on the venturi (Fig. 18.41); L Fig. 18.39 Fig. 18.40 Fig. 18.41 5. Remove the gas valve from the venturi. (Fig. 18.42); 6. Reassemble in reverse order; 7. The gas valve settings will need to be adjusted (see Section 14.3 page 28); 8. Reinstate the gas supply and test for tightness on reassembly. Fig. 18.42 52
18.4.8 Removing the heat exchanger 1. Carry out step 18.2.1; 2. Remove the air gas manifiold as in step 18.4.2 (Fig. 18.43); 3. Unscrew the three bolts “M” from the main heat exchanger (Fig. 18.44); 4. Remove the flow and return pipes and the condense drain pipe from the heat exchanger. (Fig. 18.45); M Fig. 18.43 Fig. 18.44 Fig. 18.45 5. Remove the heat exchanger from the boiler by sliding out. (Fig. 18.46); 6. Reassemble in reverse order. Fig. 18.46 18.4.9 Removing the spark generator 1. Carry out step 18.2.1; 2. Disconnect the earth cable from the ignition electrode. (Fig. 18.47); 3. Disconnect the ignition electrode, live, neutral and earth cables from the ignitor. (Fig. 18.48); 4. Remove the two screws “N” from the ignitor and remove (Fig. 18.49); 5. Reassemble in reverse order. N Fig. 18.47 Fig. 18.48 Fig. 18.49 53
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