weak spark on Glow worm 38cxi boiler?

Make sure the connections are clean and tight. The sensing/spark rod should be cleaned with a soft , clean emery cloth or steel wool.

Install a new sensor / ignitor

Ensure the ignition cable has has electrical continuity using a continuity tester or or multimeter. The resistance should be 0.1 ohms. If no continuity replace the cable.

Check the intensity of the spark
Remove the ignighter cable from the module connection.
From the module connection to the ignighter cable an arc should jump at least a 1/2 inch gap. This is good enough for most systems which have 1/8 inch gap.

Chris Smith
January 2014