High Efficiency Boiler Systems


A significant change in the North American hydronic heating industry took off and gained altitude in the mid 1990’s. Residential and light-commercial gas-fired boilers started to rapidly evolve from high-temperature, chimney-vented appliances to pressure-vented, modulating, high-efficiency condensing (mod-con) boilers.

Start Learning Right Now, For Free:
Free Course: How to Design & Sell Mod-Con Boilers with Roy Collver
Free Course: High Performance Building and HVAC 101

[Free Tool] Siegenthaler’s ‘Hydronics Design Studio 2.0’ Demo

We created the Hydronics Design Studio (HDS) to assist heating professionals in designing high performance hydronic heating systems.  It represents the state-of-the-art in computer-assisted design for modern hydronic heating systems.  Thousands of professionals use the HDS, but if you’re not yet familiar with it, I’d like to offer you a free demo version to get acquainted with the […]

John Siegenthaler Reviews Heat Pumps

In the article below, John Siegenthaler, Principal of Appropriate Designs, explains how air-to-water heat pumps offer new opportunities for hydronic pros. At the end of the article, John runs the numbers to answer the question: “How does the performance of an air-to-water heat pump compare to that of a geothermal heat pump?”  John teaches two […]

[Free Tool] How to Calculate Boiler Efficiency Gains

Roy Collver’s “Condensing Boilers in Hydronic Systems” is the most underutilized course we offer (OK, tied with Robert Bean’s HVAC Engineering). Roy has built this exhaustive educational experience that only a handful of folks have benefited from so far. We hope to change that in 2015 by giving away small pieces of his course so people […]

December 8th, 2014|Categories: Boilers, Free Courses|Tags: , , , |

Heating with Biomass: It’s Not Just About the Boiler…

This article is a guest post by John Siegenthaler, Principal at Appropriate Designs and expert instructor with HeatSpring. John’s 10-week online course, Hydronic-Based Biomass Heating Systems, teaches engineers, heating contractors, and installers how to design and install highly-efficient biomass heating systems.

TAKEAWAYS: 

In this article, John explains why it is wrong to assume that using a high-efficiency biomass […]

Troubleshooting Condensing Boilers in Hydronic Systems – What is the System Doing?

This a guest post from Roy Collver. Roy is a condensing boiler expert. Here’s what John Siegenthaler, author of “Modern Hydronic Heating,” says about Roy’s work: “When I have a detailed question about the inner operation of a modulating / condensing boiler, Roy Collver is the first person I contact. The investment in Roy’s HeatSpring course is a fraction of the cost of a single mod/con boiler, but it will teach you concepts, procedures, and details that will return that investment many times over.”

Learn from Roy

Free. Roy is teaching a two-part free course on how to sell mod-con boilers. The second live lecture is happening on Wednesday, July 30th. Sign up for the free mod-con course here.
Paid: Roy Collver teaches an advanced 5-week course on mastering condensing boiler design in hydronic systems with the folks at HeatSpring. If you need to increase your skills and confidence around selling, quoting, designing, setting up controls, or troubleshooting condensing boilers in new construction or retrofit applications, this course is for you. Each session is capped at 50 students, but there are 30 discounted seats. Get your discount and sign up for Condensing Boilers in Hydronic Systems.

Enter Roy…

Understanding the Simple Basics

Cold weather is never too far away in most parts of North America. Be ready when it hits, and review the basics of hydronic system operation so you can quickly locate the problems that always come up. When you approach an operational hydronic system it will exhibit one of the following six states. Quickly understanding what you are dealing with will greatly reduce head-scratching time and point you in the right direction. Standing slack-jawed in front of a boiler with no clear path to determining what is wrong is very uncomfortable and a waste of time. Confidence is a key factor in successful troubleshooting, and to be able to indicate to a customer what the BASIC problem is right away buys you time to be able to work the problem, find out the SPECIFIC cause, and fix it. Using this guide as a quick reference should help speed the troubleshooting process along.

Hydronic systems are all about Delta T (the difference in temperature between the heating fluid, the system components and the surrounding air and objects). Heat always travels to cold, and if heat is not added to the heat transfer fluid (usually water), the fluid and all of the components in the system will eventually cool down to the temperature of the surroundings.

THINGS TO LOOK FOR:  NO POWER – NO FUEL – PILOT OUT – MANUAL RESET SAFETY OFF – NO CALL FOR HEAT – FLOW SWITCH OR LOW WATER CUT-OFF TRIPPED – DEFECTIVE BOILER COMPONENT (GAS VALVE, VENT DAMPER, IGNITOR, ETC.)

The boiler is on and the hot combustion gases create a large Delta T between the combustion chamber and the water in the surrounding heat exchanger. Because heat travels to cold, the water heats up. The circulation pump moves the hot water through the distribution piping to the terminal units. The terminal units heat up and a Delta T develops between the hot terminal units and the colder air. The air will get warmer at the expense of the water, which cools slightly. The cooler water circulates back through the system back to the boiler where it is heated up again. If the heat going into the boiler is more than the system can use, the water will continue to get hotter until the boiler cycles off on its operating control. The temperature difference between the water leaving the boiler and the water returning to the boiler will be “normal” for the system (usually 15°F to 40°F depending on the load and system design).

The boiler is on, adding heat to the water, but for some reason the hot water is not circulating through the distribution piping to the terminal units. The terminal units will cool down to the temperature of their surroundings and a “no heat” condition will result. The water in the boiler will continue to get hotter until the boiler cycles off on its operating control or internal high limit control. The supply and return piping near the boiler will be close to the same temperature.

THINGS TO LOOK FOR:  –  NO POWER TO PUMP – DEFECTIVE PUMP (BURNED OUT MOTOR, WORN IMPELLER, ETC.) – BLOCKAGE IN PIPING (TOTALLY PLUGGED “Y” STRAINER, CLOSED VALVE, CRUD BUILDUP BLOCKAGE, ETC.)

The boiler is on, adding heat to the water, but the hot water is not circulating fast enough through the system. The first terminal unit may become warm, but because the water is moving so slowly, all of the usable heat is transferred out of it before it gets very far. The last terminal units do not become warm enough to heat the space and a “not enough heat” condition will result. The water in the boiler will continue to get hotter until the boiler cycles off on its operating control or internal high limit control. There will be a large Delta T between the water leaving the boiler and the water returning to the boiler. (The supply will be a bit hotter than normal, but the return will be much colder than normal.)

THINGS TO LOOK FOR:  –  DEFECTIVE PUMP (WORN IMPELLER, ETC.) – PARTIAL BLOCKAGE IN PIPING (PLUGGED “Y” STRAINER, CRUD BUILDUP, PARTIALLY CLOSED VALVE, ETC.)

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