Dan Holohan Associates, Incorporated Pumping Away: And Other Really Cool Piping Options for Hydronic Systems

A small book that fixed big problems in my hydronic jobs

I remember the first time I moved a circulator from the return to the supply and tied it to the expansion tank connection per the “pumping away” method. The homeowner’s complaints—noisy pipes and stubborn air issues—vanished. That single change, explained plainly and convincingly in Pumping Away, paid for the book on the spot. Since then, this 128-page manual has lived in my service bag, dog-eared and coffee-stained, because it keeps helping me do cleaner installs and faster troubleshooting.

What the manual actually gives you

Pumping Away is a compact, approachable guide to hydronic pumping and piping. It doesn’t try to be a complete hydronics course. Instead, it focuses tightly on:

• Where the circulator belongs and why
• How pressure behaves around the “point of no pressure change” (the expansion tank connection)
• Near-boiler piping that minimizes air problems and improves circulation
• Common piping arrangements (series loops, monoflo systems, primary–secondary, and gravity conversions)
• Practical pump selection without drowning you in math
• Tricks for purging, balancing, and avoiding callbacks

What stands out is how clearly the book connects field symptoms to piping realities. You’re not just told “put the pump on the supply.” You see the pressure story behind it, and once you see it, you’ll want to rework the jobs that never quite behaved.

The “pumping away” concept in practice

The anchor idea is simple: put the circulator so it “pumps away” from the expansion tank connection. Doing so adds head to the system where it matters, increases the pressure at high points, and helps microbubbles collapse at the air separator. In the field, that translates to:

• Faster purging and fewer air-bound zones
• Quieter radiators and baseboard
• Less cavitation at the pump
• Smoother start-ups after service or a refill

On one retrofit of a 1950s gravity system, I had been fighting uneven heat and frequent bleeding. After re-piping the near-boiler side to pump away, adding a proper air separator, and respecting the point of no pressure change, the system settled down. The upstairs bedrooms warmed evenly with no manual bleeding. That job convinced me the book’s main thesis isn’t just academically sound—it saves hours in the field.

Clear drawings and memorable explanations

The diagrams are simple but effective. You see each configuration before and after, with arrows and captions that highlight where pressure rises or falls. The text uses plain language and a bit of gentle humor that makes the concepts stick. The author has the knack for telling “this is what you’ll see on a call” stories and then showing the piping detail that prevents the problem in the first place.

A few sections I’ve returned to repeatedly:

• Primary–secondary piping: Clean, no-nonsense layouts that prevent pump conflict and mixing issues, especially important with mod-con boilers and mixed-temperature loads.
• Monoflo and series loops: What you can get away with when adding a zone, and where you shouldn’t push your luck.
• Gravity conversions: Why oversized pumps mask problems (until they don’t), and how to let physics do the quiet work.
• Air removal: Why the separator belongs where the water is hottest and how to keep microbubbles from touring the system.

Pump selection without paralysis

If you’re expecting a deep dive into pump curves and rigorous head calculations, this isn’t that book. Instead, it teaches you to think through resistance, flow paths, and interactions between zones and valves. There’s enough on sizing to keep you out of trouble, plus practical notes on check valves, zone valves versus multiple circulators, and avoiding short-cycling in small zones. For day-to-day service and residential installs, the balance of “just enough math” with field logic is spot-on.

On a recent basement finish with added panel rads, I used the guidance to keep a single ECM circulator happy across multiple small loads. The primary–secondary sketch in the book, with closely spaced tees and proper expansion tank placement, was essentially the blueprint. It started up cleanly with minimal balancing.

What it doesn’t cover deeply

No single 128-page manual can cover everything. Here are the edges I noticed:

• Modern controls and ECM circulator strategies: There’s mention of variable speed, but if you’re chasing the finer points of delta-P vs. delta-T and integrating with smart controls, you’ll need supplementary material.
• Condensing boiler nuances: The primary–secondary guidance is solid, but optimization for return temperature control and condensation management isn’t explored in depth.
• Radiant floor design math: Manifold balancing and mixing strategies appear, but comprehensive load calcs and room-by-room radiant design belong to longer texts.
• Codes and regional requirements: This is a principles-and-practice book, not a code manual. Interpret local requirements accordingly.
• Metric conventions: It’s U.S.-centric in units and examples.

None of these are deal-breakers. The book’s purpose is to give you a reliable mental model and field-proven piping patterns. It does that exceptionally well.

Field outcomes I’ve seen after applying it

• Fewer callbacks for air and noise. Proper “pumping away” with a good air separator and correct tank placement is a callback killer.
• Tidier mechanical rooms. The near-boiler piping layouts help avoid the spaghetti that grows from improvisation.
• Faster commissioning. Systems purge quickly and behave predictably when circulators, expansion tanks, and separators are in the right relationship.
• Better communication with clients. The simple explanations make it easier to justify re-piping or replacing questionable choices from past work.

Who gets the most value from it

• Service technicians who want faster, cleaner startups
• Installers tackling boiler swaps, gravity conversions, or mixed-temperature jobs
• Designers looking for practical patterns that installers won’t hate
• Advanced DIYers who want to understand cause and effect before moving pipes

Beginners will appreciate the clarity and lack of jargon. Seasoned pros will appreciate the reminders and the elegant reasoning behind details that sometimes get lost under time pressure.

Format and usability

It’s a slim, easy read—128 pages in a friendly style you can finish in an evening, then mark up for the truck. The diagrams are serviceable rather than glossy, but they do the job. The physical size makes it a true field companion. My copy has lived in a gang box and survived; I prefer that to an oversized textbook that never leaves the office.

A few actionable takeaways you can use tomorrow

• Move the circulator to pump away from the expansion tank connection; put the air separator there too, on the hottest water.
• Use closely spaced tees for primary–secondary to stop pumps from fighting and to stabilize mixed loads.
• Don’t oversize the pump to “fix” a design flaw; you’ll trade one problem for another.
• Install purge points where they’ll actually purge entire loops, not just short segments.
• Choose check valves and zone valves with the entire flow picture in mind; unintended flow paths can defeat your best-laid plans.

The bottom line

Pumping Away earns a spot in the real-world hydronics toolkit. It won’t replace comprehensive design references, but it will make your next boiler room quieter, more stable, and easier to live with. The writing is approachable, the diagrams make sense at a glance, and the central idea—where you put the pump and why—delivers immediate improvements on the job.

Recommendation: I strongly recommend this manual for HVAC and plumbing pros, as well as serious DIYers working on hydronic systems. It turns foundational concepts into practical piping choices that reduce callbacks and make systems behave. If you want one compact resource that pays off on the very next service call or boiler swap, this is it.