Responded to a heating issue in Philadelphia, PA 19144. The tenant reported that the air was blowing cold and the system couldn’t be shut off, indicating a potential thermostat problem. Upon arrival, we inspected the furnace and confirmed that the nitride hot surface igniter had failed, preventing proper ignition. We replaced the igniter, tested the thermostat operation, and verified the system was maintaining heat throughout the home. While on-site, we also checked the customer’s toilet as requested. The furnace is now operating safely and efficiently, ensuring warmth and comfort for the residents during the winter season.