VOLTAGE RECTIFICATION AT SPARK GENERATOR (DEMAND)

Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4

Set Multimeter to DC Volts

Turn Hot Water Tap On

Slightly move spark generators top connector to expose terminal

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 DC voltage across the top terminal (spark generator) and a suitable earth connection.

vm vitodens 25 kw combi inner case top .jpg

vm vitodens 25 kw combi j27452 spg conns.jpg

Note.
1. When exposing the spark generators top terminal , ensure connector remains attached.
2. Ensure a good connection is made or misdiagnosis will occur.
3. Voltage will only be present when burner is ignited, the boiler will enter lockout after 3 attempts of ignition, approximately 30 seconds between each attempt, reset as required until test is complete.

As the burner is heard to ignite a voltage of approximately -20.0V DC or greater (e.g. -25.0V DC) should be measured, this will disappear when burner extinguishes. (see note 2.).