We are trying to hook up 24 sections of 7 heading pads. The pads are spread out over 53’ with there own pump to circulate the water with thermostat set to 30 Celsius through 1/2” pex. The 24 sections are spread out down a hallway 200’ long with 12 on each side of the hallway. The utility room is 80’ from the end of the hallway where the heat needs to generate from. Heat required per pad is 200 wats. My question is what size main line should I use and what type of water heater. My local plumbers don’t know where to start maybe I can get a answer here.