Gas Heat ESCO Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

The correct answer is A, a dirty filter, would cause the temperature limit safety switch to shut off the burner. When a filter is dirty, it restricts airflow, leading to the heat exchanger becoming too hot. This triggers the temperature limit safety switch to shut off the burner to prevent overheating and potential damage to the system or a safety hazard.

Options B, C, and D are incorrect because although fan motor failure, high gas pressure, and low gas pressure can all cause issues with the burner operation, they are not directly related to the temperature limit safety switch shutting off the burner due to overheating caused by a dirty filter.