Viadrus K4 - Page 34

Servicing
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Fig. . 20 Boiler wiring diagram (extra-low voltage)
BT SAFETY THERMOSTAT BT1 EXCHANGER THERMAL FUSE BTr ROOM THERMOSTAT MV1 FAN PS1 WATER PRESSURE SENSOR P2 HW FLOW SENSOR Q1 PUMP Y100 GAS VALVE
LEGEND: A1 CONTROL BOARD WITH LCD SCREEN A6 ROOM INSTRUMENT OPENTHERM B2 HEATING WATER SENSOR B3 HOT WATER SENSOR B7 RETURN WATER SENSOR B8 FLUE GAS SENSOR B9 EXTERNAL SENSOR