Responded to a report of a whistling noise coming from Sheryl’s recently installed Thermo Pride furnace. The homeowner reported that the noise occurred during operation, typically when the system first started, but not consistently or at any specific time of day. I began by inspecting the blower fan and burner components; all were secure, and I was unable to recreate the noise initially. I adjusted the blower fan speed and retested the system. When I partially obstructed the front face of the furnace, I was able to reproduce the whistling noise. Upon further inspection, I found three small holes drilled in the top of the furnace for fresh air intake. When I covered one of the holes with tin tape, the noise increased in volume. I then drilled two additional larger holes in the intake and enlarged the existing ones to improve airflow. After reconnecting the air intake and running the system continuously, I was unable to recreate the whistling noise. I believe the issue was caused by the
