14 English 5.906-487.0 Rev. 00 (04/10)1 Air guidance to the on-demand heater2 Slider, air volume adjustment3 Stop screw, air volume adjustment4 Return to fuel tank5 Fuel hose supply to the fuel pump6 Connecting cable of solenoid valve and fuel pump7 Access opening of fuel pressure adjustment8 Fuel pump9 Suction opening, burner blower10 Fuel filter11 Fuel line from fuel pump to burner12 Fuel hose supply to the fuel filter13 Fuel tankFuel pumpThe fuel pump is connected directly to the motor shaftvia the coupling piece and the blower wheel. It alsofeeds fuel from the tank and back via the return dur-ing cold water operation. This lubricates the toothedwheel pump.During warm water operation, the installed solenoidvalve and part of the fuel reaches the burner throughthe fuel nozzle and is ignited there.The fuel pressure is adjusted via the central settingscrew.During dry runs, the fuel pump will block.The coupling piece serves as a nominal breakingpoint.1 Cable connections for fuel solenoid valve2 Safety clip3 Fuel filter4 Fuel hose5 Supply6 Fuel solenoid valve 230 V7 Adjustment screw for fuel pressure8 Fuel line to burner nozzle9 Return to fuel tank10 Fuel hose11 Screw connection of fuel line5.5 Burner blower with fuel pump