Burner was off on reset. Reset the control and it started. Checked the ohms, the cad cell was reading 1300 ohms which will cause it to go off on reset. Adjusted the cadcell eye and it was reading 540 ohms. Installed a used Beckett primary control to see history and ohms. While the water heater was running, the furnace turned on and 10 seconds later the water heater went off on reset. Replaced the oil filter at the wall. Started and checked operation. It was still doing the same thing. After the furnace was satisfied, checked the oil flow at the water heater and noticed a little bit of air. The oil tank is under ground and can not see the level. The customer had 100 gals added on Dec 9. Recommend having another delivery due to issue.