F.348 — Burner in fault state: Gas modulation valve issue

What does F.348 mean?

The burner is in a fault state related to the gas modulation valve. This may occur in systems with multiple boilers or indicate a flue issue.

• Incorrect 'Multiple connections' setting for common flue system (multiple boilers)
• Restricted flue system flow
• Faulty gas fan unit

Click steps to track your progress.

1. 1

   If multiple boilers share a common flue, check that the 'Multiple connections' setting in the commissioning assistant is correct.

2. 2

   Check the flue system for any obstructions or restrictions in flow.

3. 3

   Reset the boiler by briefly turning off and on its power supply. If the fault persists, contact a qualified heating engineer.