Gas Heat ESCO Practice Exam

A furnace with a high temperature rise indicates which issue?

1. Blocked exhaust

2. Dirty filters

3. Fan speed too slow

4. Incorrect burner pressure

The correct answer is: Fan speed too slow

A furnace with a high temperature rise indicates an issue with the fan speed being too slow. The temperature rise in a furnace is the difference between the temperature of the air entering the furnace and the temperature of the air exiting the furnace. If the fan speed is too slow, it doesn't blow enough air over the heat exchanger, causing the temperature rise to be higher than normal. This can lead to overheating of the system and potentially damage components. Options A, B, and D are not correct in this context: A. Blocked exhaust would typically result in a low temperature rise, as the heat produced by the burner would have difficulty escaping the system. B. Dirty filters could also lead to a low temperature rise, as restricted airflow would not allow for efficient heat exchange. D. Incorrect burner pressure could cause issues with combustion but would not directly result in a high temperature rise if the fan speed is adequate.