English 5.906-432.0 Rev. 00 (06/15) 471 Rubber collar2 Lock3 Air door, air volume adjustment4 Stop screw5 Burner blower1 Solenoid valve2 Coupling unit3 Connection pressure line4 Setting fuel pressure5 Fuel pump6 Fastening screwUninstall fuel pump– Detach pressure line.– Unscrew locking screws.– Remove the fuel pump.Fuel pumpThe fuel pump is connected directly to the motor shaft viathe coupling piece and the blower wheel. It also feeds fuelfrom the tank and back via the return during cold water op-eration. This lubricates the toothed wheel pump.During warm water operation, the installed solenoid valveand part of the fuel reaches the burner through the fuelnozzle and is ignited there.The fuel pressure is adjusted via the central setting screw.During dry runs, the fuel pump will block.The coupling piece serves as a nominal breaking point.1 Fastening screws blower cover2 Fastening screw blower wheel3 Coupling unit4 Blower wheel5 Fuel pumpBurner blowerThe blower supplies the burner with combustion air.The air flap is used to adjust the air value to optimisedcombustion values.The blower wheel is mounted to the motor shaft by meansof 2 feather keys.