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
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.
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
We have made it to the new year, a new decade. And with the turn of every calendar comes the rush of industry trade shows. Next week we will be traveling to Las Vegas for the IBS/KBIS Show or the Builder’s/Kitchen & bath Show. Following that, we will be in Orlando for the AHR Show Read more
We have made it to the new year, a new decade. And with the turn of every calendar comes the rush of industry trade shows. Next week we will be traveling to Las Vegas for the IBS/KBIS Show or the Builder’s/Kitchen & bath Show. Following that, we will be in Orlando for the AHR Show, North America’s largest HVAC show. Oh yeah, let’s not forget about World of Concrete, back in Vegas. The goal is to see, feel and test new products, learn and network with fellow attendees.
When attending these trade shows, it is best to have a plan. Having attended dozens of these show in the past, I have come up with some tips and strategies for a better trade show experience.
- Map Out Your Plan — All of these shows have corresponding websites with maps, and a list of exhibitors and events. I can’t stress enough to map out your day so you are the most efficient with your time, energy and steps on the trade show floor. (ahrexpo.com & www.buildersshow.com & www.worldofconcrete.com) Downloading the appropriate trade show apps is a must.
- Wear Comfortable Shoes & Clothing — We all want to look good, and professional, but gone are the days of stuffy apparel. I’d rather feel comfortable and fresh at the end of the day than out of sorts, sweaty and dogs a barking.
- Give Yourself Enough Time — The stress of a trade show can be daunting in and of itself. Take as much time as you need to take a deep breath and move freely on the show floor. It’s always a good idea to come in the day or night before a show to make sure all is in order and registration for the show is set. If you are planning a night out, make sure you make any necessary reservations ahead of time.
- Afterparty Over-Indulging — We all love to go out and enjoy ourselves, especially after a long day at a show. There are numerous manufacturer parties, dinners, soirees, etc. where one can relax and wind down. But staying out all night—and drinking—can be fun, and up to your discretion, but it isn’t advisable, especially if you intend to be at the show the following day. Nobody is impressed with the over-perspired, alcohol lingering on breath, bags under the eyes, headache pounding visit from on overserved attendee. Pro Tip: Keep hydrated and carry a protein bar just in case you get the munchies. The IAQ in these large buildings is usually very poor and the air can get dry.
- Plan Accordingly for Transportation — Most of the time at busy trade shows, transportation can, well, be a bitch, especially after a show. Keep this in mind as long taxi lines will form to and from the shows. Download your favorite rideshare app so you are locked and loaded.
- Travel in Packs — If traveling in groups, try to stay in one place or area. It alleviates costs on transportation and makes meetings much more amenable.
- Be Prepared to Exchange Contact Info — Make sure you have business cards on hand and be prepared to exchange info digitally, so make sure your phone is charged or bring extra chargers! Also, make sure you have proper badges for the show. For example, attendee, exhibitor and press badges all provide different access and different access times. Make sure you understand the limitations of your particular given badge.
- Follow-up with Contacts — Once the show is over, what it your end game? What better way to measure the results of a show personally than to document leads, follow up with new contacts, and were you satisfied with your expectations of information, contacts and overall impressions?
- Cellular/WiFi Service — Most shows do not offer WiFi on the show floor, or if they do, it usually sucks. There are certain spots at different venues you may be able to sneak a signal, maybe. Make sure your service is covered in the areas where you are, or be prepared to go without in the dark recesses of a concrete building.
- If Unable to Attend … — Be sure to follow your favorite social media outlets that are attending (Search Mechanical Hub on Facebook, Twitter & Instagram) and keep up to date on what’s going on from the show floor. First of the year trade show events are when companies have big product announcements, launches and press briefings.
Good luck, and have a great trade show experience!
Hydronic systems outperform VRF, study finds In a study commissioned by Xylem Inc. that evaluated HVAC systems in a number of South Carolina school buildings, hydronic systems outperformed all other systems, including VRF, in terms of lower energy use, cost and life expectancy, by as much as 24%. “With HVAC systems dictating a substantial amount Read more
Hydronic systems outperform VRF, study finds
In a study commissioned by Xylem Inc. that evaluated HVAC systems in a number of South Carolina school buildings, hydronic systems outperformed all other systems, including VRF, in terms of lower energy use, cost and life expectancy, by as much as 24%.
“With HVAC systems dictating a substantial amount of the overall energy use of commercial buildings, the results shed light on the importance of evaluating varying system-to-system costs before installation,” said Kyle DelPiano, Business Development Director, CBS Market, Xylem. “More than ever, energy-efficient practices are driving the construction industry toward more sustainable solutions, and this study proves long-term cost savings that can’t be overlooked when making the choice between hydronic and VRF systems.”
To compare and contrast HVAC systems according to their 30-year life-cycle cost analysis (LCCA), the Xylem study analyzed seven elementary and middle schools located in South Carolina Climate Zone 3A, a humid, warm climate. The cost analysis included upfront installed cost, replacement cost allocations and ongoing energy and maintenance cost of the following system types:
- Variable refrigerant flow heat pumps (VRF)
- Water source heat pumps (WSHP)
- Ground source heat pumps (GSHP)
- Direct expansion rooftop units (DX RTU)
- Water cooled chillers (WCC)
- Air-Cooled Chillers (ACC)
The findings of the study revealed that the schools with WSHP, GSHP and WCC systems displayed energy use levels that were 30%, 41% and 25% better than the national median for elementary and middle schools, respectively. The replacement cost allocation also acknowledged that the tested hydronic systems operate effectively for approximately 25 years, as opposed to the 15-year replacement estimation for VRF systems.
The tested VRF systems required replacement a decade earlier because of their tendency to work harder during heating cycles, bringing proof of long-term cost savings to the forefront of the conversation surrounding sustainability and hydronic HVAC system efficiency.
Replacement allocations had an impact on the life-cycle cost analysis (see yellow bars) and drastically reduced the cost effectiveness of equipment with 15-year life expectancies.
Considerable benefits of the hydronic HVAC systems included lower energy usage intensity and cost, wider range of maintenance flexibility and longer life expectancy.
Finding and installing Heating, Ventilation, Air Conditioning & Refrigeration (HVAC&R) applications for high-pressure systems has become more difficult as international regulations have eliminated some common refrigerants. R22, for example, is set to become illegal on January 1, 2020, due to its high global warming potential (GWP). With this in mind, the industry has begun developing Read more
Finding and installing Heating, Ventilation, Air Conditioning & Refrigeration (HVAC&R) applications for high-pressure systems has become more difficult as international regulations have eliminated some common refrigerants. R22, for example, is set to become illegal on January 1, 2020, due to its high global warming potential (GWP). With this in mind, the industry has begun developing sustainable, durable tubing materials.
Some copper tubing designated for HVAC&R applications does not provide the wall thicknesses necessary to handle the temperatures and pressures of carbon dioxide systems. However, copper-iron (C19400) material offers high strength, good thermal conductivity, and great workability, making it an exceptional, sustainable tubing option for HVAC&R applications. The C19400 alloy is rated for pressures in the range of 90 bar (1,305 psi) to 130 Bar (1,885 psi) and above at operating temperatures up to 300°F, compatible with the operating ranges of CO2 refrigeration systems.
Brazing techniques for copper-iron alloy are the same as those for brazed joints in standard copper and copper alloy systems for plumbing, HVACR, medical gas and other systems that require strong, leak-free, fatigue-resistant joints.
- First, measure the copper iron alloy tube accurately and precisely, so it will completely fill the socket when inserted into the fitting.
- Cut the tube square to the desired length.
- Deburr the inside edge of the tube and chamfer the outside edge.
- Clean the outside of the tube and inside of the fitting cup(s) to ensure the surfaces to be brazed are free from dirt, oxides or other contaminants that can impede the flow of filler metal into the joint.
- Assemble the joint by inserting the tube into the socket hard against the stop. The assembly should be firmly supported so that it will remain in alignment during the brazing operation.
- To conduct heat into the joint space, first preheat the tube. For a horizontal joint, begin preheating the bottom 2/3 of tube for a distance approximately equal to the depth of the fitting cup. When the tube begins to darken, begin heating both the tube and the fitting cup, focusing on the bottom 2/3 of the joint.
- Heat until the fitting cup reaches the proper brazing temperature; temperatures vary by tube size and type and can be found in section 14.4a of the Copper Tube Handbook.
- Apply heat to the parts to be joined, preferably with an oxy-fuel torch with a neutral flame. Heat the tube first, beginning about one inch from the edge of the fitting, sweeping the flame around the tube in short strokes at right angles to the axis of the tube (Figure 7.18, Position 1 [see below]). It is very important that the flame be in motion and not remain on any one point long enough to damage the tube.
- Switch the flame to the fitting at the base of the cup (Figure 7.18, position 2 [see above]) and heat the fitting cup around the bottom 2/3rds of the joint.
- As the fitting cup rises to brazing temperatures, begin to heat both the tube and the fitting by sweeping the flame (Figure 7.18, position 3) [see above] from the fitting to the tube until both the tube and the fitting reach the temperature at which the brazing metal begins to melt when applied to the copper-iron surface. Avoid excessive heating of cast fittings, due to the possibility of cracking.
- For 1-inch tube and larger, it may be difficult to bring the whole joint up to temperature at one time. It frequently will be found desirable to use an oxy-fuel, multiple-orifice heating tip to maintain a more uniform temperature over large areas. A mild preheating of the entire fitting is recommended for larger sizes, and the use of a second torch to retain a uniform preheating of the entire fitting assembly may be necessary in larger diameters. Heating can then proceed as outlined in the steps above.
- Apply the brazing filler metal at a point where the tube enters the socket of the fitting, near the bottom portion of the assembly. When the proper temperature is reached, the filler metal will flow readily into the space between the tube and fitting socket, drawn in by the natural force of capillary action. Keep the flame away from the filler metal itself as it is fed into the joint. The temperature of the tube and fitting at the joint should be high enough to melt the filler metal.
- Keep both the fitting and tube heated by moving the flame back and forth from one to the other as the filler metal is drawn into the joint and move the flame and filler metal smoothly and continuously up one side of the joint assembly. Once you reach the top, move back to the bottom of the joint on the other side and repeat the process, overlapping filler metal addition at both the bottom and top of the joint.
- When the joint is properly made, filler metal will be drawn into the fitting socket by capillary action, and a continuous fillet of filler metal will be visible completely around the joint. To aid in the development of this fillet during brazing, the flame should be kept slightly ahead of the point of filler metal application. Inspect to make sure there is a complete fillet around the joint, if necessary you can reheat the face of the joint and add additional filler metal to complete the fillet.
- For vertical joints, the starting point (bottom of the horizontal joint) is irrelevant but the same heating and brazing process should be followed.
- Cleaning is not a requirement once the brazing process is completed. If flux was used, the residue should be removed. This can most easily be done with hot water and brushing.
- Your joint is now complete! For additional information related to brazing copper-iron alloys and copper piping in HVAC systems, check out CDA’s Copper Tube Handbook.
Copper-iron alloy’s effectiveness under high pressure distinguish it as a top material for HVAC&R applications. The development of copper-iron alloy is a huge step forward in creating piping applications that are fit for the future environment. For more information about proper installation techniques for copper-iron, check out the video: Copper-iron Piping for HVAC, Lightweight but Strong as Iron.
Professionals in the commercial trades who have made the switch from copper or CPVC to PEX for plumbing or mechanical piping will tell you there are four main reasons why: speed, cost, reliability and safety. Because in today’s fast paced commercial building environment, change is rapid and inevitable, budgets and schedules are tight, competition is Read more
Professionals in the commercial trades who have made the switch from copper or CPVC to PEX for plumbing or mechanical piping will tell you there are four main reasons why: speed, cost, reliability and safety. Because in today’s fast paced commercial building environment, change is rapid and inevitable, budgets and schedules are tight, competition is fierce, and skilled labor is shrinking, so keeping valuable employees safe is paramount.
The commercial industry needs a piping solution that can meet all those very important needs, and PEX delivers on every front.
Because PEX pipe is flexible to bend with each change in direction and the connections are quick to learn and even faster and easier to make, it’s a great solution to meet the skilled-labor shortage challenge and also rapidly accommodate necessary changes in the field.
For example, a PEX piping system in an in-suite multifamily or hospitality project can reduce the number of required fittings by more than half compared to rigid copper or CPVC that require a connection with each change in direction. That can shave days or even weeks off the production schedule, depending on the project size.
Additionally, with today’s aging buildings, PEX is even more beneficial in re pipe applications where existing structures need minimal invasion for renovation (think: historical buildings).
When it comes to cost, every professional in the commercial world agrees — if the cost is attractive, but the product fails, it’s not worth it. PEX has proven to be both cost-effective and durable, a combination that makes it a win-win for engineers, building owners and installers alike.
Contractors are also finding it’s not just the material costs that are reasonable, it’s also the labor costs that PEX helps manage. Because the flexible pipe requires fewer connections (and those connections are faster and easier to make), it cuts down on labor costs in addition to the bill of material cost for the product.
With materials costing on average up to 30 percent lower than copper, and installs taking up to half the time compared to rigid systems like copper and CPVC, PEX is proving itself to be a smart solution that installers can rely on for consistent pricing, bidding and installations.
Every contractor has experienced a leak at one time or another, so a piping material that can help minimize leaks is a huge bonus. Take a look at all the ways PEX helps minimize potential leaks:
- Because the flexible pipe can bend with each change in direction, it reduces the number of fittings and connections and, in turn, the potential for leaks.
- With the PEX cold-expansion fitting system, it is impossible dry fit a connection. The expansion method requires the pipe to first be expanded before inserting a fitting. Then, as the pipe shrinks back down, it creates a strong connection onto the fitting. Eliminating the potential for dry fits means there’s never a concern if the connection is made.
- Flexible PEX is highly resistant to freeze damage because it can expand to accommodate frozen water in the system and then contract back down after the water thaws.
- PEX resists corrosion, pitting and scaling, so there is zero chance of leaks or performance issues due to any of these factors that can plague metallic piping systems.
With worker safety becoming a bigger issue — especially with the skilled-labor shortage — PEX offers benefits due to its lighter weight. For example, a 300-foot coil of ½-inch PEX weighs about 18 pounds, whereas the same amount of copper pipe weighs around 85 pounds.
Lighter weight means easier maneuvering around the jobsite, less strain on the body and a reduced need for cranes and heavy-lifting equipment.
Also, because all the PEX connection methods (cold expansion, crimp, clamp, compression or push-to-connect) do not need chemicals or open flame, it greatly reduces risk on the job site and also eliminates the need and cost for fire watch requirements.
One last word of advice
Stick with one PEX system brand. Mixing brands for the pipe, fittings, sleeves or rings can greatly reduce (or even void) the warranty. You’ll have more confidence knowing you have the backing of one company if you ever have a service or warranty issue.
If you’re interested in learning more about PEX pipe and fitting systems, visit the Plastics Pipe Institute website at plasticpipe.org or the Plastic Pipe and Fittings Association website at ppfahome.org.
Kim Bliss is the content development manager at Uponor. She can be reached at firstname.lastname@example.org.