Fuel overflow pipe and possible ignition defect

Fuel overflow pipe


BA 4 heaters no longer have a fuel overflow pipe. Stocks of previous heaters can be used up.

Possible defects on BA 4 heaters which cause safety switch to operate

Both pictures show glow-spark plug connectors which have been damaged by arcing.


In Fig. 1 a small hole can be seen in the connector. It was caused by arcing between the glow-spark plug connector and the low voltage terminal.

Fig. 2 shows a connector which has a hole burnt in it due to arcing between the copper core of the wire and the vehicle body.

These defects can cause ignition trouble and actuate the safety switch during the start-up process or when the heater is regulating.


  1. Replace ignition wire and connector if necessary. To facilitate installation, the wire can be cut 50 mm (2 in.) longer than the original wire.original wire.

  2. Route the ignition wire so that it does not come into contect with the body.with the body.

  3. Bend the low-voltage terminal of the glow-spark plug far enough away from the connector so that sparks can no longer jump across.away from the connector so that sparks can no longer jump across.