VOLTAGE SPARK GENERATOR AT PCB

Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4

Set Multimeter to AC Volts

Turn Hot Water Tap On

Gain access to PCB (use Insulation Mat as required)

WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure

Mains Power On

Measurement:

If required, reset boiler, press mode and ok for 2 seconds.
Allow self-check to complete and ignition sequence to commence.
Measure for A/C voltage across the brown and blue wires of connector 54.
Expected voltage, mains voltage (see note 3.).

vm vitodens 25 kw combi j27488 pcb conns 1 .jpg

Note.
1. PCB connector numbers can be found on the plastic moulding surrounding the board.
2. Ensure a good connection is made or misdiagnosis will occur.
3. Voltage will only be present during the sparking phase of ignition (approximately 5 seconds), the boiler will enter lockout after 3 attempts of ignition, approximately 30 seconds between each attempt, reset as required until test is complete.