We are trying to get several unfinished items signed off for inspection in order to sell our house. When our addition was done we relocated the water heater which required an extension of the gas line. We have attempted to pressure test the gas line but it won't hold pressure. Initially we replaced the gas shut off valve on the water heater as well as the clothes dryer. The only remaining outlet would be the floor furnace. We went under the house and checked all accessible joints, tees & unions including the point at the floor furnace, with a soapy solution. No leaks were evident yet we still cannot get the line to hold pressure. Any suggestions on where we go next? We are presently in the process of completely removing each valve and capping the lines off but are not able to do this with the floor furnace. Any advice would be greatly appreciated.