The pump should be installed immediately downstream from this point, "pumping away" from it.
: Dan Holohan is well-known for his expertise in hydronics and heating systems. If "Pumping Away" relates to his work in this area, it might focus on the design, installation, or troubleshooting of hydronic heating systems, emphasizing the importance of proper pumping techniques.
The expansion tank is the anchor of the system. Holohan teaches that the circulator creates a pressure differential. By placing the expansion tank on the suction side of the pump, the pump’s impeller "sees" a constant pressure. This prevents cavitation (the formation of vapor bubbles in the pump), which destroys circulators. Pumping-away-by-dan-holohan-pdf
The spot where the expansion tank connects to the piping system is called the "Point of No Pressure Change."
In the world of hydronic heating, few names are as respected—or as entertaining—as . His book, Pumping Away and Other Really Cool Piping Options for Hydronic Systems , has long been regarded as a foundational text for heating professionals, contractors, and DIYers looking to understand how to correctly pipe heating systems. The pump should be installed immediately downstream from
Let’s address the elephant in the room. You are likely searching for a free digital copy (PDF) of this book.
"Pumping Away" by Dan Holohan, often called the "little purple book," introduced the "Point of No Pressure Change" (PONPC) concept, transforming modern hydronic heating system design by encouraging installers to pump away from the expansion tank [1]. By placing the circulator on the supply side, the pump adds pressure to the system, which prevents air entrainment, eliminates noisy cavitation, and fixes cold radiators [1]. For more information on the principles of hydronic heating, you can visit the HeatingHelp.com website. The expansion tank is the anchor of the system
Holohan famously states: Never put the expansion tank on the discharge side of the pump. If you do, the system pressure drops everywhere else, causing air to be pulled into the system through valve packings and auto-air vents, leading to corrosion and noise.
If you hear water trickling or banging, it's often a sign that you are not "pumping away." Conclusion
Many of Dan Holohan’s books, including Pumping Away , are available in Kindle format, which is a convenient way to get a PDF-like, instant-access experience legally. 3. Industry Training