How far from wall should I drill hole in floor to run gas pipe with shutoff valve, installing the valve to the pipe from the floor, leaving me enough room to put a shutoff valve (being able to turn valve to tighten to black pipe) between metal pipe and flex hose going to wall heater?

Hi Ricky

Have you looked at the installation manual... it should have a diagram showing basic installation requirements?

If you don't have the installation manual you need to get one. If you don't have one let me know the model number and name brand and I'll see what I can come up with, OK?

Mark