n Tools & Instruments

Cordless threading

Milwaukee Tool, Milwaukee, Wisconsin, introduces its all-new cordless threading machine. The pipe threading machine is ideal for use with Milwaukee’s new line of universal pipe threading dies and is compatible with other universal style dies. It features a collapsible cart and is built with gas springs to assist the tool up to working height. When moving the machine, the self-contained oil reservoir keeps oil within the basin and eliminates the need to drain the oil. For jobs requiring threading and grooving, the machine’s rear hammer chuck enables a quick transition and connection of roll grooving attachments without teardown or use of additional adapters. It can thread up to two-inch black iron pipe, stainless steel, rigid metal conduit, and more.

Milwaukee Tool www.milwaukeetool.com

Video inspection solution

Teledyne Flir, Wilsonville, Oregon, launches its newest videoscope series, the Extech HDV700. The videoscope is ideal for automotive, building inspection, plumbing, manufacturing, and HVAC technicians. With a selection of eight maneuverable probes, professionals can inspect difficult to reach areas with the use of one hand. Each kit is complete with an HDV700 videoscope screen, camera probe (model dependent on kit ordered), 32 GB micro-SD card, USB-A to USB-C cable, HDMI type A to type D cable, li-ion rechargeable battery, and universal adapter.

Teledyne Flir www.flir.com

Vacuum pump

Navac, Lyndhurst, New Jersey, introduces the NP7DP — a dual voltage vacuum pump with expanded applications. Its features a twocylinder design and can vacuum down to 15 microns. Integrated cylinder structures coupled with forced oil circulation, assures performance. The built-in hook makes it easy to carry to a high workplace. It features a dual-stage, AC motor and weighs 26 lbs. The NP7DP vacuum pump comes with a one-year warranty.

Navac www.navacglobal.com

Drain cleaning

All-new compact press tool

DeWalt, Mississauga, Ont, introduces its new 20V Max compact press tool and several new jaw and ring press attachments for plumbers, pipefitters, and HVAC/R technicians. The new press tool provides press versatility in a compact design that allows for trouble-free pressing in small spaces. In addition to the compact press tool itself, new attachments allow for pressing pipes larger than 1-1/4 inch. The press tool is ideal for work in overhead and one-handed press applications. Onboard design features include a 180-degree rotating head, an LED light, Crimp Connect software to generate data from successful press cycles, as well as Tool Connect software.

DeWalt www.dewalt.com

Ridgid, Elyria, Ohio, announces its new FlexShaft drain cleaning machine. The Ridgid K9-12 features a fully enclosed housing, which contains 30-ft. of FlexShaft cable, encapsulated in nylon sheath. It is ideal for pipes that are 1-1/4inch to two-inches in diameter. The FlexShaft cable is spun by attaching a cordless drill to the input shaft on the housing. As the cable spins, the chain knocker attached will expand to provide wall-to-wall pipe cleaning. It can clean soft blockages, build-ups, and grease in sinks, tubs, showers, urinals, and floor drains.

Ridgid www.ridgid.com

Math doesn’t have to be difficult unless we make it so. If we struggle to understand or grasp a particular topic, it often reflects more on the instructor than the subject itself. Personally, I had a strong dislike for math during my school days. I vividly recall my math teacher asserting that I would never amount to much without his calculus class. Needless to say, I proved him wrong.

While I may not be on the same level as some of my peers, I am far from sitting on the sidelines. As Martin Luymes, vice president of government relations at the Heating, Refrigeration, and Air Conditioning Institute of Canada (HRAI), rightly points out — math would be more enjoyable if it

By Michael Ridler

were made more relevant to real-world applications.

Instead of focusing solely on abstract concepts like solving Pi, why not prioritize teaching practical skills such as calculating GPM and flow velocities? With that in mind, as someone heavily involved in hydronic design work, I believe it’s crucial to discuss some essential formulas and share simple “hacks” that make field calculations easier.

It’s important never to shy away from math and, more importantly, not to ignore it. Just because a designer has performed the calculations doesn’t mean they are always correct. Those of us involved in design work greatly appreciate installers who double-check and validate our designs. It’s a collaborative effort, and even though your training may be less formal, your years of experience hold as much, if not more, weight than that of the designer (speaking from personal experience in both installation and design work).

For this session on hydronic math, let’s consider a 2,000 sq. ft. house with a total load of 54,000 btu/h. Our goal is to heat this house using a boiler and a radiant floor heating system. Let’s dive into the math and demonstrate how quickly we can transform this information into a comprehensive hydronic package using nothing more than a notepad.

Turning loads into flow

We know that our home has a total load of 54,000 btu/h. The simplified formula for turning your btu/h into a flow is as follows:

That 10,000 represents a 20-degree Delta T across a radiant floor heating system, which is a common Delta T we see in residential system design. When you look at any heat loss and want to get a rough idea of your flow rates for a radiant floor heating system, the easy math is to divide the total load by 10,000. So in our case, our house load of 54,000 get divides by 10,000, which is 5.4.

Let’s look at that formula and get into the details for a second. Let’s start with the somewhat complete formula and work our way to the simplified formula.

The choice of Delta T can vary, but my personal preference is always a Delta T of 20 degrees or less. Some may opt for a 10-degree Delta T (such as applications where you have a lightweight overpour with ceramic tile to minimize temperature fluctuations), which is acceptable. However, it is crucial to avoid using a super wide Delta T in your hydronic design for a building as it can lead to uneven heating and discomfort in the space.

The value of 500 is a simplified approximation used in the sensible heat rate equation for water. It should be noted that this value is not applicable to systems that incorporate glycol, and it also changes with variations in water temperature and density. Nevertheless, for our purposes, it is more than accurate enough. Now, let’s substitute the Delta T with the previously mentioned 20-degrees and observe how our formula is transformed.

Calculating the amount of radiant tubing

When it comes to hydronic design, determining the required amount of radiant floor tubing is a crucial step. One important consideration is that the piping component is often the least expensive part of the project. By installing more tubing, you can futureproof your design as the industry transitions from boilers to heat pumps. You can even use a simple calculation to demonstrate this point by multiplying your total square footage by the value in my table for the tube spacing you have selected.

For instance, let’s take a 2,000 sq. ft. home where I want to maintain an even temperature at a low water temperature. In this case, I’ll opt for a nine-inch spacing between the tubing. Using the formula, I calculate the required tubing length as follows — 2,000 sq. ft. multiplied by 1.33, which equals 2,660 ft. of pipe.

Some installers and designers still use 12-inch spacing or even 18-inch spacing.

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However, with an 18-inch spacing residential tubing job, the solution often involves increasing the boiler temperature, leading to higher monthly operating costs.

Caution is essential as we approach the era of hydronic heat pumps. Adjusting water temperatures arbitrarily on equipment can result in increased maintenance or even catastrophic failures. Additionally, in other webinars, I’ve demonstrated how choosing to save $500 on tubing can add hundreds of dollars to monthly operating costs. Let’s consider our 2,000 sq. ft. home again. If we calculate it with 12-inch tubing, the result is 2,000 multiplied by 1, which equals 2,000. Assuming a cost of 50 cents per foot for PEX pipe, the project with 9-inch spacing costs $1,330, whereas the house with 12-inch spacing amounts to approximately $1,000.

Calculating manifolds

Now that we have determined our total home load to be 54,000 btu/h and the required flow rate of 5.4 GPM, let’s move on to calculating the number of manifolds needed for our system. Additionally, since we are using 9-inch spacing, we know that we will require 2,660 ft. of tubing.

Determining the required number of manifolds is a straightforward process. Assuming we are using half-inch tubing, which is commonly used in 90 per cent of residential hydronic systems, we can simply divide the total tubing length by 300. This value of 300 represents the maximum length specified by the CSA B214 standard for halfinch PEX tubing.

You might wonder why we are suggesting the maximum length of 300 right away. The reason is that the CSA B214 standard allows for a buffer of +10 per cent, meaning the actual maximum length per half-inch circuit is 330 feet. In our case, we will divide the total tubing length of 2,660 ft. by 300, resulting in approximately 8.86 manifolds. Of course, it’s not practical to have fractional manifolds, so this means we will have 8 circuits that are 300 feet long and one circuit that is shorter. Consequently, we will need a total of 9 manifolds for our system.

Calculating header pipe sizing

velocity for water in a copper tube system is five to eight ft. per second (FPS) for cold water systems, four to five FPS for hot water systems below 140 F, and two to three FPS for hot water systems with a temperature exceeding 140 F. Therefore, we design our heating systems around a flow rate of two to three FPS.

The minimum flow is based on two-ft. per second, while the maximum flow is based on four ft. per second. For a flow rate of 5.4 GPM, you can select either a threequarter-inch copper pipe, which will be on the higher end of the velocity range or opt for a one-inch pipe, if you prefer to be on the lower end.

However, it’s important not to oversize the piping. Choosing excessively large pipes can introduce potential issues and unnecessary coststhatyourcompetitors,whoproperlysize their systems, may avoid.

With all this information, we now have a comprehensive understanding to complete our design. We know that the load is 54,000 btu/h, the flow rate is 5.4 GPM, and we will be using 2,660 feet of half-inch PEX tubing with a nine-circuit manifold, all fed by threequarter-inch piping.

Sizing the circulator

Now that we have determined the total load, required GPM, amount of PEX tubing, and the number of manifolds, the next step is to size the header piping that feeds the radiant manifold. In this article, we will assume that the manifold is in the mechanical room and copper piping is used for the supply.

When sizing copper piping, it is crucial to consider flow velocities. Maintaining the recommended maximum velocity is important to prevent noise and potential long-term system issues.

As per the Copper Development Association, the suggested maximum

The next step in our process is sizing the circulator,whichrequiresknowingthesystem pressure drop. I learned a simple trick from my close friend Dave Holdorf at Taco, which provides a reliable estimation of head loss in most cases. If you’ve completed the previous step of properly sizing your header pipes, you’ll be amazed at how accurate this basic formula can be compared to a long-form calculation.

In our scenario, where the manifold is in the mechanical room and we have a short 20-ft. of three-quarter-inch copper pipe

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