Contents 5
6. Replacement of Parts
134
6.1 Replacement Procedure
134
6.2 Components Replacement Instructions
134
6.2.1 PCB
134
6.2.2 Fuse
135
6.2.3 Fan Motor (Combustion Air)
135
6.2.4 Flame Rod
136
6.2.5 Ignition Transformer
137
6.2.6 APS
137
6.2.7 Main Gas Valve
138
6.2.8 Condensate Trap
139
6.2.9 Flow Sensor
140
6.2.10 Circulation Pump
141
6.2.11 3-way Valve
142
6.2.12 Water Pressure Sensor
143
6.2.13 Space Heating Strainer
143
6.2.14 Auto Feeder Valve
144
6.2.15 DHW Heat exchanger
144
7. Components Diagram and Part List
145
7.1 Case Assembly
145
7.2 Burner Assembly
146
7.3 Waterway Assembly (NCB)
148
7.4 Waterway Assembly (NCB-E)
150
7.5 Fan (Gas) Assembly
152
8. Inspection and Maintenance Schedule
154
8.1 Annual Servicing
154
8.2 Maintenance Report
154
8.3 Maintenance Schedules
154
8.4 Inspection Report
154
