Performed a heating pm on an oil furnace and oil hot water heater. Brushed and vacuumed. Replaced the oil filter, nozzles and strainers. Replaced the air filter- customer supplied. Started and checked the safeties. Performed a combustion test. Furnace- 7.0% o2, 21 ppm, 87.9% efficient Hwh- 4.9% o2, 31 ppm, 87.2% efficient System is operating properly.