Will a 20 lb propane tank run the cooktop on dual fuel range converted for LP?

No, a 20 lb propane tank will not be able to run the cooktop on a dual fuel range converted for LP. The minimum recommended propane tank size for a dual fuel range is a 100 lb tank. This is because the cooktop on a dual fuel range converted for LP requires a higher pressure of propane than the cooktop on a natural gas range. A 20 lb propane tank cannot provide this higher pressure.