Dan Holohan teaches us about gravity hot-water heating systems. Classic gravity heating is both the simplest and the most complicated system of all. It’s simple because it has few moving parts. The water is the only true moving part. Hot water rises; cold water sinks; it’s that simple. But at the same time, it’s complicated because the pipes have to be just the right size for the amount of water that’s flowing, and they have to have the perfect pitch. The fitter has to make sure to remove the burrs from the pipes he cuts, otherwise there could be too much friction presented to the flow. Want to learn more? Visit heatinghelp.com/. Want to be an expert? Get a copy of Dan Holohan’s book Classic Hydronics: www.amazon.com/Classic-Hydron...