I have been heating with my OWB for two years now and I have been curious about adjusting the boiler for use in one of my hobbies - Brewing Beer. When brewing beer I need to bring wort to a boil. To bring it to boil I was thinking about adding a pressurized loop (relief valve at 30psi) with the pressurized loop all copper so I dont have pex failure. I want to separate the boiler water from the wort, but I am not sure what heat exchanger would work best in this situation. I would like to use an immersion coil but I am not sure what dia and length I would need. Does anyone know what the BTU output of a 1/2OD (3/8 ID) X 25' ft coil would be? The pump is a grundfos 1/25 at up to 17gpm.