Buried propane tank ran dry about 3 years ago. I'm not filling it. We are loading up the moped and the family is headed to the Smoky mountains for Thanksgiving so I need to keep the pipes from freezing. I ve heard that you can just take a smaller tank and hook it up in the basement to the furnace. My question is where?? I have since removed my propane water heater so there is an easy access here. My question is this. If I hook it up to where the water heater was wont the propane try to backfill into my buried tank in the yard? Do I need to cap it off to prevent this?