What could be the issue if a customer reports that the furnace blows cold air at the end of the heating cycle?

When a customer reports that the furnace blows cold air at the end of the heating cycle, one potential cause is related to the fan operation settings. If the fan is set to run continuously, it may continue to run even after the heating cycle has completed, causing unheated air to be circulated. This typically results in the sensation of cold air blowing when the furnace is no longer actively heating.

In this scenario, the fan's operation settings are crucial. If the fan control is set to "on," it will operate regardless of whether the furnace is heating. This can lead to the perception of cold air at the end of the heating cycle since the heater has already turned off, but the fan continues to blow air through the ducts.

The other options do not directly address the specific issue of cold air blowing after the heating cycle completes. For example, a faulty thermostat may cause the furnace not to activate, but it wouldn't specifically contribute to cold air being blown at the end of a cycle. A clogged air filter may restrict airflow and cause other symptoms, but again, it doesn't explain the cold air issue. Adjusting the heat anticipator relates to the timing of the furnace’s operation but does not directly rectify the concern of cold air blowing after heat shuts off