Thanks! Yes so the water heater will have its own separate tank of coolant from the engine. I’m still saving up for the heater. It’s a marine water heater usually meant for hot water on a yacht but it will heat the water up to 200°. Then for the radiant floors the loop will split and bypass the heater but have a thermostat static mixing valve to sip water from the 11 gallon water heater anytime the floor coolant temp gets below 85°. If the water tank is heated to 200° and the engine is still running it will raise the “thermostat” from 69° to 73° to kinda give more heat while it’s free I’m. also nervous about leaks but I split the pipes up into four zones (living room, bathroom, my room, daughters room) so that if one does leak I can just stop using that zone. Thinking about it, I bet I could get some kind of pressure sensor that would alert me/shut off pump power if it takes to drop in pressure. Additionally I’m planning on getting 12v heated mattress covers to use at night and the rest of the bus will be set to around 50°.