Classic Hydronics Seminar
In this all-technical three-hour seminar, Dan Holohan will give you a Liberal Arts education in those Classic Hydronics systems. He’ll have you seeing inside the pipes as...
Hot-Water Heating → Gravity Hot-Water Systems Help Topics
This section is your guide to hot-water heating systems with information about system design and piping, air elimination, pumping away, primary-secondary pumping, valves, radiators, troubleshooting tips, and more.
Recent Articles in Hot-Water Heating → Gravity Hot-Water Systems
Mark Honeywell’s Solution to Stratification in Gravity Systems
Dan Holohan discusses one of Mark Honeywell’s contributions to gravity hot water heating. He wanted to create even heat throughout the building, so in 1909 he solved the ...
How Gravity Hot-Water Heating Systems Work
In this video, 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 s...
Converting From Gravity to Pumped Flow
Here's a full day's work compressed into a couple of minutes, courtesy of our friend John Cataneo's Dropcam. There's a lot to consider when moving a hot-water system from...
Some Gravity-Hot-Water Systems Didn't Have Compression Tanks
It all started when a friend called to tell me about this old gravity hot-water system that had him baffled. “There’s no expansion tank anywhere on this job,” he said. “Y...
Sizing Circulators for Old Gravity-Hot-Water Heating Systems
When servicing old hot-water heating systems that originally circulated by gravity, but now use circulating pumps, I began to notice a lot of oversized circulators. In so...
Adjusting the Flow Rate for an Old Gravity-Hot-Water System
About eight blocks from my house in Baltimore, there is a large two-family house with an equally large hot-water heating system that originally circulated by gravity. The...
Mixing Passive and Active Heaters Can Lead to Problems
Sometimes, you just have to think like air. The house had been sitting on this old Connecticut street for more than 100 years. Children, grown and long gone, had once ski...
Gravity Hot Water Heating Q&A
Q: How long has gravity hot water heating been around? A: Gravity hot-water heating began quietly in the United States between 1875 and 1885. It was a Canadian import, a ...