Service Type: No Heat – Diagnosis & Furnace Service Client Concern: No heat call. Inspection & Findings: - Furnace found in error code mode with four flashes, indicating an airflow issue. - Air filter inspected and found to be older and highly restrictive. - Power reset; furnace ignited and operated. - With current filter installed, noted loud whistling, very high static pressure, and significant strain on blower motor. - After approximately 10 minutes of operation, temperature rise increased excessively and the high temperature limit tripped due to restricted airflow. - Replaced filter with another filter available on site; airflow improved significantly and high temperature limit did not trip. Work Performed: - Diagnosed airflow restriction causing no-heat condition. - Replaced restrictive air filter. - Cleaned and serviced furnace to ensure optimal performance. - Tested furnace operation after service. Recommendations: - Existing filters on site are MERV 12; if used, they must b