I am installing a Paloma PH-28CDVSP Commercial Direct Vent Gas Tankless Water Heater. LP I have an 11" w.c. 250,000 BTU regulator from my tanks and less than 5 foot of line to inside my house 3/8" copper tube that goes to a 3/4" rigid pipe to enter house and back to a copper tube. With that said the max input BTU's for this unit is 199,000. I have to run 12' to get to the unit and the only other appliance on this is a cooktop, no furnace, nothing else. The propane co. told me I can use the existing 3/8" tubing to supply the unit and should not see a starvation issue, I am beginning to wonder with all of the reading I am doing. any input would be great. Oh and the unit will heat water up to 180 degrees at full throttle which I will never use. (yes it is overkill but got the unit for less than half price for a residential unit of the same temp rise/flow.) Thanks