Heater not heating. Heating repair and maintenance tune up. Diagnose and perform annual heater maintenance service plan on Comfortmaker heating system. Replace filters and check furnace on 8 year old HVAC system. Heater maintenance complete which will help lower heating cost for this residential customer. Evaporator coil is leaking. Recommend replacement evaporator coil, leak repair, or new Comfortmaker air conditioning system. Heating system is now ready for December weather.