Preformed furnace maintenance on 3 year old 96% Lennox heater. Upon my maintenance I noticed a few point of concerns that were addressed with the homeowner. Furnace- 1. System had no surge protection on both furnace and condenser 2. Furnace had no trap 3. 1 inch not filtering out enough dust and debris particles. This is causing build up within the system. Conducted leak search and found no signs of leak refrigerant leaks. Although did tighten core done on service port of suction side. Recommended that pressure are checked just before the summer to ensure no issues.