Customer did not answer door , rang door bell and knocked
Performed diagnostic on 3 year old furnace. System is not heating. Cycled system for heating. System initiated heating sequence , but pressure switch failed to close. Found pressure hose was ripped or possibly chewed through by rats. Repaired hose and cycled system. System went through proper heating sequence of operations and started heating. Filters on both units extremely dirty. Replaced both filters with approval. Cycled system. System is fully operational upon departure.