Boiler shows E28, often related to flue or condensate issues, no ignition

Safety first: Condensate is mildly acidic; avoid skin and eye contact.

User checks:

• Inspect the external condensate pipe for freezing or blockage. If frozen, thaw gently with warm water and lag the pipe to prevent recurrence.
• Check that the pipe has a continuous fall and is not kinked or crushed.
• Reset the boiler once after clearing any obvious blockage.

Professional actions:

• An engineer can remove and clean the internal condensate trap, check the flue, and test any condensate level sensors.