F70 Fault — Invalid Device Specific Number (DSN)

What does F70 mean?

This fault occurs if the display board and main PCB were replaced at the same time and the Device Specific Number (DSN) was not reset or is incorrect. It relates to incorrect or missing output range coding resistance.

• Display board and main PCB replaced at same time and DSN not reset
• Incorrect or missing output range coding resistance
• Incorrect coding resistors

Click steps to track your progress.

1. 1

   Check that the DSN is set correctly (requires installer access).

2. 2

   Verify the coding resistor for the gas type on the board (Yellow Nat Gas 806 Ohms / Grey LPG 1180 Ohms).

3. 3

   Try unplugging and replugging the coding resistor located next to the expansion vessel.