Diagnosis
The vacuum switch hose was disconnected or damaged during cleaning. The controller uses this hose to detect fan pressure. Without it, the controller thinks the fan isn't running and dumps pellets in a failed attempt to establish a vacuum.
How to Fix It
Power off and unplug the grill. Locate the vacuum switch, a small black plastic box mounted near the control panel. Find the clear plastic hose running from it to the fan housing. Ensure both ends are pushed on securely. Inspect the entire length of the hose for cracks, kinks, or melting. Replace if damaged.
If That Didn't Work
The vacuum switch itself may be faulty. You can test it. With the hose connected and the grill on SMOKE, listen for a faint click from the switch about 30 seconds after startup. No click indicates a failed switch.
Heads Up
Always note hose and wire routing before a deep clean. This hose is critical for the safety feed system. A disconnected hose will cause an overfeed and potentially a dangerous amount of smoke on ignition.