I'm planning on installing a tankless water heater that maxes at 160K Btu. I only have a 1/2" line from the meter to the furnace(75K) in the same room. The city told me that there is 2lb gas from the meter to the house. The sizing charts that I found say that 1/2" 2psi black pipe will handle the btu draw for both the furnace and the water heater. I know I will need to use a regulator at the water heater to step down to 7" w.c. or so. I will also need to adapt the 1/2" line to 3/4" for the water heater. My questions are:
1) Will the 1/2" 2lb line be enough? 2) Should I convert to 3/4" before the regulator to the water heater?
Thanks for any input.