[Electrical] - What are the B4 and S3 terminals for on the X Series burner?
There are 5 terminals on the X Series burner.
3 are inputs;
- N (Neutral).
- Earth.
- L (live).
2 are outputs;
- B4 gives an output for a burner run light if you have one on the boiler panel, otherwise it is not used.
- S3 gives an output to a remote lockout light if you have one on the boiler panel, otherwise it is not used.