Today I arrived on site Troubleshooting: Addressed the no heating issue in the 1st fl leaving room system. Fault Identification: Found a 7-flash error code, indicating a dirty flame sensor and dirty filter. Maintenance: Determined the system needs a tune-up and Duct cleanings. Upon arriving at the property, the client explained to me that the heating on the 1st floor stopped heating. The client directed me to the basement where the unit is. I proceeded to verify the system. I found the unit displaying an error code of 7 flashes. Indicating a lockout. I proceeded to check the electrical components. I found the flame sensor dirty. I proceeded to clean it. I also found the air filter in the wrong position. Install a new filter provided by the customer. AprilAir 213. I suggested the client to consider installing the 210 filters to avoid airflow restriction. The client said to take this into account. I started the system and monitored for about 20 minutes. The system did not