90 or 99 - Air intake or vent exhaust blocked

What does 90 or 99 mean?

These codes indicate that the air intake or vent exhaust openings are blocked. Proper airflow is crucial for safe and efficient operation.

• Obstructions (leaves, nests, debris) blocking vents
• Improperly connected vent pipes
• Vent terminal too close to obstructions

Click steps to track your progress.

1. 1

   Visually inspect the air intake and vent exhaust openings for any blockages.

2. 2

   Carefully remove any debris found.

3. 3

   Ensure vent pipes are securely connected and not damaged.

4. 4

   Verify that the vent terminal meets clearance requirements (see page 27).