Honeywell Ignition transformer ZT930 1MM 13121

The Honeywell Ignition transformer ZT930 1MM (SKU 13121) is a device that steps up the mains supply voltage of 220 V at 50 Hz to a secondary voltage of 15 kV, generating a spark for gas ignition in burners and boilers. It is designed for operation in ambient temperatures up to 80 °C and has an ingress protection rating of IP54, indicating dust and splash resistance. This transformer is energized only during the ignition phase and is de-energized once flame is proved.

When selecting a replacement ignition transformer of this type, verify that the primary voltage matches the burner's supply (e.g., 220 V), and that the secondary voltage and current are compatible with the electrode gap. Check the physical mounting dimensions, terminal arrangement, and the high-voltage cable connector pattern to ensure a proper fit. The cable must be silicone-insulated to withstand heat and voltage stress; inspect it for cracks or hardening before installation.

Common failure modes for ignition transformers include internal short circuits, open windings, or breakdown of the high-voltage cable insulation. Symptoms may include no spark at the electrode, weak or intermittent sparking, or spark leakage to earth, which can be mistaken for a faulty transformer. Check the ignition cable for damage and verify the transformer's output with a suitable tester.