I will always preach that a successful cast iron water boiler installation begins with proper planning. I worked for an oil company for 20 long years, and nine years of that I was a service manager. During this time, I came across many problematic jobsites. I would evaluate the installation issues and try to figure Read more
water heating
I will always preach that a successful cast iron water boiler installation begins with proper planning. I worked for an oil company for 20 long years, and nine years of that I was a service manager. During this time, I came across many problematic jobsites. I would evaluate the installation issues and try to figure out where the problems had started. This knowledge has greatly helped me as a Training Manager for U.S. Boiler Company. Now, after 40 years in the heating business, I know how important proper boiler installation planning really is for reducing the number of problem jobs and expensive callbacks. In fact, planning is much easier than you may think …
- Proper boiler sizing. Complete a thorough heat loss calculation. Do not fall into the trap of oversizing the boiler because you sized it based on the old boiler size or you measured the connected radiation load, and never allow the customer to talk you into a larger boiler than needed. Today, with physically smaller boilers and less water volume, oversized boilers will short cycle more than ever. Increased short cycling means higher maintenance, higher fuel costs, and higher installation costs.
- Follow the boiler Installation & Operation (I&O) Manual. Be sure to follow one of the suggested near boiler piping options listed in the manual. The boiler tapping may not have to be the same size as the manifold piping. Use the flow charts for pipe size. You can pipe the boiler the same size as the tapping, or in some cases, use smaller piping dependent on the heat loss requirement. When the heat loss is known and the proper boiler size is chosen, you may be able to use smaller air separators, expansion tanks, and piping. You can use the following as a guide to size the boiler and system piping:
- 3/4” pipe = 40,000 BTU’s @ 4 – 5 GPM (gallons per minute)
- 1” pipe = 70,000 BTU’s @ 7 – 8 GPM
- 1-1/4” pipe = 160,000 BTU’s @ 16 – 18 GPM
- Bypass piping. Bypass piping is discussed briefly in the I&O manual. We cannot continue to install modern cast iron boilers the same way we used to install boilers with larger water volumes. When needed, a bypass system should be installed to protect the boiler. There are primary/secondary piping and circulated bypass options, both of which we will discuss later in this article.
The bypass system discussed in the manual is called a “boiler bypass” and is always installed the same size as the supply and return headers. When adjusted, the water flow through the boiler is slowed so the water spends more time in the boiler. This allows the boiler temperature to increase faster and decreases the possibility of boiler condensation. This means that some of the system return water is bypassed around the boiler and enters the supply beyond the boiler. I know what you are about to say. “Well, that will cool off the supply water going to the homes heating system!” That is correct, but it is not a problem. This is what I call a “poor man’s outdoor reset.”
The system will run quieter and the system water temperature will increase slowly until the radiation outputs enough heat to satisfy the thermostat. The colder it gets outside, the hotter the system supply water temperature will be. When the valve placement is installed as shown in the manual, we can easily adjust the ΔT through the boiler. Simply put, leave the bypass valve open and adjust the flow through the boiler with either valve located on supply or return pipes below the bypass pipe to slow the flow and force more water through the bypass. Partially close one of these valves and check the ΔT through the boiler. You will need a minimum of a 20°F rise. If this is a large water volume system, like cast iron radiation, increase the ΔT through the boiler to 35 – 40°F ΔT.
Quick Tip: If the bypass is hotter than the return pipe, the flow is backwards and you have piped a system bypass as opposed to a boiler bypass. Follow the piping in the manual to verify correct installation.
- Primary/secondary piping option. Primary/secondary piping utilizes hydraulic separation so that the water flow from system pumps do not affect boiler pump flow. This allows us to reduce the flow through the boiler to heat the water faster and heat the water to a higher temperature without affecting the flow in the system. In other words, we can have a higher flow in the system and a lower flow in the boiler. We still want a minimum of 20°F rise through the boiler, and for higher water volume systems we want a higher ΔT near 35°F – 40°F.
- Variable speed bypass pump option. To have the best boiler protection, install a variable speed bypass pump with a temperature sensor. This will change the speed of the pump to obtain the proper return water temperature. We offer a variable speed bypass kit with instructions for gas water boilers. This will protect the boiler in a high-water volume system or radiant in-floor radiation application.
Quick Note: My concern, and the reason for the above discussion of boiler protection from condensation, is excessive water flow through the boiler and slower temperature increase. I have experienced multiple boiler installations where the ΔT through the boiler is less than 20°F. In fact, I have witnessed some as low as 8°F. Lower ΔT’s are a result of excessive flow, possibly caused by the number or circulator sizes installed on the system. So, what is the minimum flow rate on cast iron water boilers? Look in the I&O manual under specifications and find the DOE heating capacity (MBH) of the boiler. For instance, the Series 3 model 304B has an input of 105k MBH and a DOE heating capacity of 88k MBH. Divide the DOE output by 10,000 to discover the maximum flow required by the boiler. If your flow exceeds that number, the ΔT will be less than 20°F. You can use this hydraulic formula to determine flow rate through the boiler.
- Avoid short cycling. Short cycling is caused by lower water flow, or higher ΔT. Higher ΔT may mean that the circulator is to small, the boiler is oversized, or the valves not adjusted properly. Generally, the minimum boiler flow should be half (but not limited to) of the maximum boiler flow.
Boiler Flow Formula:
Q/(500*ΔT) = Flow
Q = DOE Heating Capacity
Let’s put some numbers to that formula. Let’s assume that a boiler has a ΔT of 15°F. The Series 3 model 304 (referenced above) has a DOE heating capacity of 88,000.
88,000/10,000 = 8 GPM. This is the maximum flow required by the boiler. Divide this in half to get the minimum boiler flow. In this case, it would be 4 GPM.
Now, back to the formula.
Q=88,000
ΔT = 15°F
88,000/(500 * 15) = Flow
88,000/7500 = 11.7 GPM
The flow is almost 4 GPM higher than the maximum flow the boiler should have. This tells us we need to achieve a 20°F ΔT, which means less flow through the boiler. Why do we have to much flow? There are oversized pumps or to many pumps. Using a bypass or primary/secondary strategy above, we can easily correct the flow through the boiler.
- Vent the boiler properly. If the boiler is chimney vented, the local and federal codes apply. A chimney liner may be required. If the unit is direct or power vented, the manufacturer dictates the venting according to the certifications obtained during testing. Since this article applies to cast iron water boilers, a sidewall vented boiler requires AL29-4C vent pipe. No plastic!
- Outdoor air. I like to use outdoor air as much as possible to verify enough combustion air. Plus, there is less chance of contaminated air.
- Gas pressure. Check the incoming gas pressure and the manifold (outlet) pressure with other gas appliances running. Check all safeties. Finally, always complete a combustion check.
Ron Beck is Outside Technical Advisor and Manager of Training for U.S. Boiler Company, where he’s been since 1998. Ron’s 34 years of experience in the heating industry include climbing the ranks of a HVAC company, from apprentice to service manager. Currently, he’s the go-to solution guy for contractors in the field.
Ron can be reached at RBeck@usboiler.net
Arlington, Va. — The Air-Conditioning, Heating, and Refrigeration Institute (AHRI) filed a petition with the U.S. Court of Appeals for the Fourth Circuit challenging the validity of a Department of Energy (DOE) regulation on Commercial Packaged Boilers. “AHRI is asking that the Court review the rule because of our belief that the Department overstepped its statutory Read more
Arlington, Va. — The Air-Conditioning, Heating, and Refrigeration Institute (AHRI) filed a petition with the U.S. Court of Appeals for the Fourth Circuit challenging the validity of a Department of Energy (DOE) regulation on Commercial Packaged Boilers. “AHRI is asking that the Court review the rule because of our belief that the Department overstepped its statutory authority by issuing a rule that will impose an undue and significant burden on boiler manufacturers and consumers,” said AHRI President & CEO Stephen Yurek. Of primary concern to AHRI is that because it ignored legally required procedures, DOE adopted a rule that does not save a significant amount of energy and is not cost-effective.
“The Department ignored a statutory requirement that it establish clear and convincing evidence that the rule results in significant energy savings that outweigh the costs imposed. Congress mandated specific protections for rules on commercial equipment, but in this case, DOE wrongly decided that those rules don’t apply,” said AHRI General Counsel Caroline Davidson-Hood. “We are therefore filing suit to hold the Department accountable and ensure that future rulemakings adhere to statutory requirements,” she added.
Rochester, NH — Laars Heating Systems, a subsidiary of Bradford White Corporation, has appointed Lou G. Vorsteveld, Ph.D., to the position of Director of Engineering. Vorsteveld is an international executive with notable success in both sales and engineering. “Lou is an exceptional executive who combines an expert’s understanding of the products wemanufacture with the real-world Read more
Rochester, NH — Laars Heating Systems, a subsidiary of Bradford White Corporation, has appointed Lou G. Vorsteveld, Ph.D., to the position of Director of Engineering. Vorsteveld is an international executive with notable success in both sales and engineering.
“Lou is an exceptional executive who combines an expert’s understanding of the products wemanufacture with the real-world experience and demands of the business community,” said Laars Heating Systems Vice President & General Manager, Rich Simons. “His track record demonstrates a leadershiprole that focused on the steady and successful delivery of high-quality products to meet the ever-changing demands of our customers. He is an important addition to our team.”
“Every engineer wants to work with companies that boast a line of first-class products driven by asuperior business program,” Vorsteveld said. “Laars meets these standards, and I look forward tocontributing to the company’s product development and growth.”
Vorsteveld will oversee Laars’ engineering functions, including project execution, design quality,strategic technology direction and development, and optimal design for manufacturing, and work closely with engineering resources across Bradford White Corporation to ensure continued development of best- in-class products to all Bradford White subsidiary customers.
Vorsteveld holds a Ph.D. in mechanical engineering, with a focus on thermal sciences and combustion engineering, from the University of Vermont.
Before joining Laars Heating Systems, Vorsteveld was Vice President, Engineering, and a vital member of the management team at AERCO International. He has also served previously as President and CEO of Bosch Thermotechnology/Buderus Hydronics as well as other executive level engineering, operations, quality and sales roles at Bosch/Buderus and Triangle Tube.
In his leisure time, Vorsteveld enjoys boating, water skiing and residential renovation.
Laars Heating Systems is a subsidiary of the Bradford White Corp. It is one of the nation’s leadingmanufacturers of boilers and volume water heaters for both residential and commercial heating. For more information, visit, www.laars.com.
Thursday, Aug. 22 12 noon – 1:00 p.m. CDT Have you ever received a call from a large multi-family complex with residents complaining about instantaneous domestic hot water availability? Worse yet, have you been called out to investigate and repair pinhole leaks in a building’s DHW circulation return system? New to the series, Mark Eatherton Read more
Thursday, Aug. 22
12 noon – 1:00 p.m. CDT
Have you ever received a call from a large multi-family complex with residents complaining about instantaneous domestic hot water availability? Worse yet, have you been called out to investigate and repair pinhole leaks in a building’s DHW circulation return system? New to the series, Mark Eatherton is eager to share how he resolved a 40-year old recirculation problem that threatened to shut down a large, multi-family subsidized housing project due to a lack of readily available DHW in the building.
You’ll learn:
→ Where do I begin when balancing an existing system? What are the priorities?
→ What are the biggest challenges in correcting a poorly functioning system?
→ How do I size and apply thermal balancing valves in retrofit applications?
There aren’t many situations that Mark hasn’t encountered and resolved in his 40+ year career in the industry. He is a licensed Master Plumber (Colo.) and a licensed Master Mechanical Contractor under the ICC auspices. Did we mention that he loves to teach, write and educate and has been doing so for over 25 years? An avid supporter of the Radiant Professionals Alliance, he is employed by Advanced Hydronics, Inc. where he is responsible for designing, managing, training and troubleshooting tough plumbing and hydronic related problems.
Coffee with Caleffi technical training webinars are free and intended for contractors, designers and wholesalers. All attendees receive a Certificate of Attendance following event. By submitting your webinar registration, you are consenting to email communications to keep you up-to-date on industry news. Please note that your personal information is respected and NOT shared externally.
Whether for a single family home, large-scale apartment complex, or commercial or industrial facility, installing a boiler system is a significant investment requiring thoughtful consideration to ensure heating comfort, reliability and efficiency for years to come. Building owners, facility managers, engineers and contractors seek systems that meet specification requirements, installation ease, serviceability, reliability, lower operating Read more
Whether for a single family home, large-scale apartment complex, or commercial or industrial facility, installing a boiler system is a significant investment requiring thoughtful consideration to ensure heating comfort, reliability and efficiency for years to come. Building owners, facility managers, engineers and contractors seek systems that meet specification requirements, installation ease, serviceability, reliability, lower operating costs and higher performance. Once these major parameters are met, buyers also should consider design details that may set one boiler apart from another.
Installation Ease
The installation process can significantly impact the overall cost of any new boiler system. Look for a boiler with design features that aid in simplifying the installation process, thus saving time and money.
An integrated control system that offers a user-friendly setup wizard with intuitive controls will simplify the boiler installation process for contractors.
Boilers with a “door-fit” design are ideal for applications that have limited access. Not having to tear out a wall or door frame can save thousands in installation expense. Likewise, boiler room floor space is always at a premium so zero clearance boiler designs where boilers can be placed side-by-side with minimal clearance is also desired. The key here is that the boiler still remains serviceable.
Sometimes getting a fork lift at the installation site is harder than one would think. Smart packaging and mobile design features that mitigate this need should be a purchase target. Integrated unloading ramps that come as part of the shipping container make the unpacking process quick and easy. Couple this feature with integrated roller casters and the boiler rolls on to the site and is easily positioned into place. If the boiler install includes a concrete pad, the shipping ramp can be used to move the boiler on to the pad as well.
For efficient operation with multiple boilers consider a control system that will fluidly connect different systems to work synchronously to ensure the highest level of performance and efficiency.
Having a correctly-leveled surface is a prerequisite to proper boiler operation and performance. Boiler designs with integrated leveling legs perfectly level the area. Simply position the boiler in place and adjust the leveling legs, which are very similar to the leveling legs on a household appliance but are industrial grade to support the weight of the boiler.
There are a variety of boiler controls on the market that offer varying setup processes and functionality, ranging from simple to complex. An integrated control system that offers a user-friendly setup wizard with intuitive controls will simplify the installation process for contractors. For example, all Weil-McLain condensing boilers, including the new Stainless Steel Vertical Firetube™ (SVF), Evergreen™ and SlimFit™ boilers, include this convenient setup feature in the Unity™Controller (70-3000 MBH).
High efficiency is key when selecting boilers. Weil-McLain’s SVF Stainless Steel Vertical Firetube™ (SVF) boiler can be found listed with AHRI with industry leading thermal efficiencies up to 97.1%.
Multiple pre-set systems are another popular boiler control feature. These units feature pre-set heating systems for typical operating conditions built into the controller so installers don’t have to enter specific supply or return temperatures during installation, but rather a specific application which reduces installation costs and time while increasing reliability.
Usability
Simple, user-friendly controls also are essential for efficient boiler operation long after setup is complete. Whether managing a single boiler or a system of boilers, contractors must understand how to leverage system features to optimize performance.
In a multiple boiler system, user controls will manage multiple units to deliver the desired heat and adapt accordingly as the environment changes. For variable primary flow and hybrid boiler system applications, specifically, it is important for user controls to offer configurability between different products and technology. If one boiler in a system goes down, the unified controls will communicate across the units and vary output to adjust for the loss.
Boiler room floor space is always at a premium so zero clearance boiler designs where boilers can be placed side-by-side with minimal clearance is also desired.
With a straightforward interface and simple navigation, contractors should seek controls that provide at-a-glance boiler status, diagnostics, troubleshooting and integration with building automation systems. The right control system will fluidly connect different boilers to work synchronously and ensure the highest level of performance and efficiency.
Similarly, when expanding a boiler system, controls that maximize energy across all boilers on a system reduces energy costs. Weil-McLain’s SmartSequencing™, for example, controls an algorithm that runs as many boilers as possible at the minimum input, therefore maximizing efficiency. With this advanced control feature, boilers maintain optimal efficiency through lead-lag rotation and balanced heat loading.
Maintenance & Serviceability
Boilers must be well-maintained for their benefits to be fully optimized, and the design of a boiler can have a significant impact on its serviceability over time. Proper inspection and regular native maintenance are vital to ensure uninterrupted, reliable and safe boiler operation. Therefore, contractors will appreciate boilers designed to make annual servicing easier.
Tasks such as cleaning heat exchangers, replacing worn out components, adjusting air fuel mixture, adjusting combustion controls, and maintaining water PH balance will improve boiler efficiency and reduce costly failures, while extending the lifecycle of the unit. Easy access to boiler components will make it easier for contractors to complete these and other critical maintenance activities that support a high-performing unit.
Featuring a proprietary clover-shaped, firetube design, the Weil-McLain SVF heat exchanger provides greater surface area for maximum heat transfer.
Something as simple as selecting a boiler with a hinged cover plate can make the inspection and regular wash down process easier. In these designs, the hinged cover plate can be safely propped open like the hood of a car, granting quick access to the center of the boiler, including the burner and firetubes, for inspection or cleaning. This is especially useful in more compact boiler locations where overhead space is limited.
In addition, consider a design with a serviceable condensate tray that collects condensation during combustion. A boiler designed with a replaceable condensate tray allows for a vulnerable part of the unit to be swapped out quickly and efficiently before an expensive impact to the entire heat exchanger occurs. This improves the longevity of the boiler and reduces maintenance costs considerably.
Efficiency
Commercial-sized boilers are rated according to thermal efficiency, which is the measurement of output heat from the boiler that is transferred into the overall heating system. Higher efficiency boilers offer the most by reducing annual fuel consumption and capturing energy cost savings. Reputable boiler manufacturers are rated and listed by AHRI (Air Conditioning, Heating & Refrigeration Institute), which is a North American trade association of manufacturers of air conditioning, heating, and commercial refrigeration equipment. For example, the SVF Stainless Steel Vertical Firetube™ family can be found listed with AHRI with industry leading thermal efficiencies up to 97.1%.
Opting for a higher-efficiency boiler will result in significant fuel savings for customers, particularly when replacing an older system with a much lower efficiency rating – such as upgrading from 80% thermal efficiency design to 95% or higher. Boilers can account for about 55 percent of annual energy bills, and building owners with high-efficiency boiler systems often report energy cost savings up to 25 percent or more on their heating expenses. In addition, many regions offer efficiency rebates for installing high efficiency boiler systems.
With more boilers on the market offering similar functionality and performance metrics, it can be difficult to differentiate which design is the best for each application. All the particulars that impact a boiler’s installation including usability, serviceability and efficiency can set the superior unit apart from the rest of the field, showcasing a design developed specifically with contractors’ needs in mind. The smallest design details may have the greatest impact on a boiler’s value and performance over time, so choose wisely.
John Miller is the commercial boiler senior product manager with Weil-McLain, a leading North American designer and manufacturer of hydronic comfort heating systems for residential, commercial and institutional buildings.