TROUBLESHOOTING Go with the flow when resolving heat complaints

Go with the flow

when resolving heat complaints

When we use hydronic systems to move energy around, flow is one of the drivers. Think of hydronics as a fluid-based energy transfer system. As such, hydronics is used to heat, cool, provide DHW, and many processes in commercial applications. In many cases, a circulator pump is the “motor” that moves the fluid around the loop or circuits. As a troubleshooter, a common call is for a lack of heat or hot water in a home or building. My modus operandi was to start thinking of possible causes as I drove to the call. If it was a job I had installed, or had been to before, I would start running through the layout in my mind. To move or transfer heat energy we need both flow and a temperature difference (note, there are still some gravity powered systems out there, however, this article will focus on pumped systems). We do not always have the luxury of a system design or mechanical schedule indicating the equipment that is supposed to be installed. I would venture to guess most residential systems do not have adequate, if any documentation. So, we must make some assumptions based on practical experience and an overview of the system. It does not take a lot of effort to determine a lack of flow condition. It could be as simple as laying hands on the piping to determine if fluid is moving. Most volt ohm meters (VOM) have temperature differential heads for taking temperature readings. Contact thermometers are helpful and if you have one, an infrared camera is an ideal troubleshooting tool. If in fact you are using a circulator to move flow, it needs to be sized to the job at hand. Learn the steps to properly size the circulator. There is plenty of online training to help you acquire appropriate sizing skills. Being old fashioned, I still use the Bell & Gossett System Syzer tool. B&G also offers version 4 of its System Syzer program for PCs.

Properly-sized circulator, so what’s next?

Assuming the circulator has been sized properly, next up is a review of the installation. There are arrows cast into most every circulator. Many circulators have checks installed or in the box and those too are directional. Make sure these components have been installed properly; if that is not the case make it so as you update the system. You’ll appreciate it if the installer (maybe you) included isolation valves in the original installation. Note the “what not to do” graphic − these are best practice recommendations. You and I have seen these suggestions ignored and surprisingly the system may still work. It just may not work as well as it should and you might be able to improve it. You could pipe in a workable purge arrangement. There are pump iso-valves with purge ports built in. It is well worth the money to have a quick, easy and defined way to purge a loop. Many no- or low-flow conditions can be traced to inadequate purging.

WHERE TO START ON A SUSPECTED NO- OR LOW-FLOW CONDITION

Partially filled pipe will cause foaming in circulator

Suppose you’ve confirmed as much as you are able that the pump, pipe and components are sized correctly. Some of the common suspects are: a valve that is partially closed, a plugged Y strainer, or an air pocket. A good troubleshooter then asks a few important questions of the system owner or caretaker: Has anything changed in the system? Have there been any recent modifications? Have any valves been turned off? Was the circulator pump replaced? It is time to pull out a few tools. Is the circulator powered and is it actually spinning? If it is smoking hot, it could be stuck or jammed. Occasionally shafts break. A voltmeter or even a spinner tool will not tell you that. You may need to pull the motor from the volute to confirm the shaft and impeller are functional. A dual temperature gauge allows you to read the differential across the circulator. A flowmeter is ideal in every pumped circuit. There are various quick read versions available from ½ in. to 4 in. These have a pin or handle you turn to get an instant reading without needing to connect a pressure differential gauge. Flowmeters can also serve as an isolation device.

Low head circulator may not be able to “lift” fluid over a tall air pocket. This blocks all system flow

Sloping pipe can create intermediate high points in system

GET THE AIR OUT

If you hear air in the system, there If is a good chance you have some is flow. Find a way to purge the air out, flow until it is silent. Even if the air does not stop the flow completely, it certainly can hamper heat exchange. For a large piping system purge, you may need more flow than what a fill valve can provide. A ½-in. fill line might get you in fast fill mode. It can provide around a 5-gpm fill rate, depending on the available inlet pressure. Fast fill features on ¾-in. fill valves deliver 5 to 9 gpm.

boiler

secondary circuits

STEP 1: Purge primary loop

VENT boiler circulator

dirt separator combination purge valve on each secondary circuit closely spaced tees

series primary loop

primary circulator

STEPS 2,3,... Purge secondary circuits, one at a time (including boiler circuit) A transfer pump or purge cart can speed up the purge process. A ½ hp fill pump should get you up around 10 gpm. Flow drops as pressure increases, so try and purge just below the relief valve setting − about 28 psi. If you work on larger piping, you may need more hp to get a good purge; ¾ hp and larger purge carts are available or you could build your own. There are specialty purge companies that can purge up to 24-in. diameter systems. There is no “one size fits all” when it comes to purging a system to assure flow. The piping layout, size of pipes and connection points all need to be taken into account. In some cases, you may need to add some valves to isolate and purge the system, and break it into smaller subsections. A fill valve and auto air vent may not cut it for a large complex system. Remote air vents, both manual and automatic, may need to be located at high points. On a job with a chronic air problem, you may boost the fill pressure a few GETTING psi. This may be enough to squeeze out some of those air bubbles so the flow can carry them back to a vent. You will need to check and adjust the expansion tank pre-charge if you increase the fill pressure. It is not a bad idea to check the tank pre-charge occasionally. Invest in quality microbubble type air purgers. They work faster and handle the tiny bubbles best. I feel confident that most qualified, experienced hydronics installers or designers can plan and pipe a system so that a limited number of purge points would provide a system free from any noise issues. The components are available and many schematics exist to show piping options. Talk to your manufacturer’s reps, check out the installation sheets, and search on YouTube for examples.

Bob “Hot Rod” Rohr has been a plumbing, radiant heat and solar contractor and installer for 30 years. A long-time columnist and trainer, he is manager of training and education with Caleffi North America. You can reach Hot Rod at bob.rohr@caleffi.com.

By Kolyn Marshall and Mike Breault

Kolyn Marshall is the systems engineering manager for Watts Radiant. Mike Breault is technical support specialist at tekmar. Prior to that, he held the position of senior instructional designer/trainer focusing on HVAC, drainage and thermostatics, for Watts.

Beyond the dollars, Beyond the dollars, it just makes sense it just makes sense

WALK LIKE A PENGUIN? HELL NO, INSTALL A WALK LIKE A PENGUIN? HELL NO, INSTALL A SNOW AND ICE MELT SYSTEM – IT’S FAR MORE SNOW AND ICE MELT SYSTEM – IT’S FAR MORE EFFECTIVE AND FAR LESS EMBARRASSING EFFECTIVE AND FAR LESS EMBARRASSING

It happens every year. We slip so easily from summer’s warm embrace into winter’s cold grip. By the time we realize what’s happening it is usually too late: the snow’s flying as driveways and walkways ice up. At that point, we’re helpless but to admit Old Man Winter’s got us, again, in his cold, icy grasp. Sleet, snow, ice and freezing rain dictate the boundaries for safe movement outside. It is during these moments when most of us truly see the value of snowmelt systems. Why aren’t there more of these brilliant, oh-so-practical mechanical systems installed during those lazy summer days? What are the influences that push building owners or facility managers so quickly past this option on the annual to-do list? The first issue is simply timing. Most construction projects take place during the summer months. Who is thinking about snowmelting during the summer, anyway? I should say: who, other than us? There are challenges to considering the impact 20 cm. of snow has on daily operations when it’s 85°F outside. When an interior or exterior project is being considered, take a few moments to simply ask the building maintenance person what they think. This team is the first line of defence when something goes wrong, or when it’s necessary to take additional steps to keep a facility operational. When asked, snowmelt is generally toward the top of the wished-for add-ons at facilities where winter conditions must be dealt with. For the bloke having to don winter gear and brave the elements, it’s a no-brainer. Who wouldn’t want simply to watch 10,000 sq. ft. of parking lot clear all by itself? Whether you’re seeing an occasional need to eliminate snow in Halifax, NS, or warming an emergency room entrance in Calgary, AB, a snowmelt system, properly installed, will readily answer the call.

Follow the money

There are several factors to consider when evaluating any major project. One of these is cost, which is broken down into three main categories: initial, operational, and ROI (or Return on Investment – allowing us to follow the money), and finally, another key facet of the ROI – safety. The first factor, initial cost, is an easy one. How much will this hit the wallet? Almost every project has a budget. The bigger the project the bigger the budget, but also the more complicated it is to figure out where those funds should be used. Project designers weigh the purpose of a project with the budget and do the best they can to deliver the most cost-effective solution possible. It’s generally this phase where snowmelt systems are considered and too often rejected. No one is going to deny the simple fact snowmelt systems can impact project cost. Any “add” will have to be vetted by the designer, then the owner, or board. Initial cost has to be balanced by the return. So, how do they do that? How does one justify a substantial added cost such as a snowmelt system? To do this requires looking at the next factor of cost. With operation and ROI, there are a few hard cost factors associated with snow removal. There’s the material to remove snow. This can include simple items such as ice melt and shovels, to more complicated items such as snowblowers, tractors with blades, and trucks to haul the stuff away. Anything mechanical adds initial and maintenance costs.

Don’t forget the soft stuff

The cost to the building itself is a soft cost, which is generally overlooked. Take a hotel entry for instance. Maintenance personnel blade the walk and then spread de-icer. This helps melt the walk but leaves behind a residue, or in some case, undissolved pellets.

When people walk along the sidewalk, their shoes pick up the pellets and and get ground into the carpet. In some cases, they sit on top of tile where the pellets act like a low-level acid. Over time this solution causes the tile to etch and fade, and mortar gradually deteriorates. All of this causes damage to the interior, which drives up operational costs and reduces customer satisfaction.

Another important “soft cost,” is impact to the environment. We rarely consider de-icing chemicals, tossed so blithely on the sidewalk and entryway. Eventually these chemicals get washed into the sewer or into local creeks and lakes; some make it all the way to major waterways and bays.

Despite the strong case for snowmelt solutions: the convenience, eco to traditional snow removal methods, at the end of the day, things almost always come down to hard costs.

It is important to make the case that soft savings noted above, but also hard costs related to operation. Snowmelt systems provide a unique ability to use resources normally overlooked.

Offset project costs

Commercial equipment generates heat as a by-product of operation. Cooling towers, by design, generate waste heat, which is usually simply vented to the atmosphere. Large refrigeration or cold storage units usually vent heat extracted from the enclosure.

Instead of letting these BTUs literally evaporate into thin air, why not put them to use? After all, snowmelt systems can reclaim those rogue BTUs, turning them into hard labour with no complaints from the “work crew!”

While these options help offset project dollars, the one factor rarely given the level of importance it should have is operational safety.

Consider the cost of a single – or worse – multiple slip-and-fall occurrences by customers. What’s the potential cost of a bad accident to the company whose property this happens on? If an employee falls how much do lost man-hours impact future revenue?

Falls on ice are the number one cause of winter injuries in Canada. According to the Canadian Institute for Health Information there were nearly 9,000 hospitalizations nationally in 2016-2017 that were attributed to ice and/or snow hazards.

The costs of injuries related to accidental falls due to ice are significant. In Alberta the Injury Prevention Centre estimates that falls cost the province $1.2 billion annually. In terms of liability, Robinson LLP reports that most slip and fall claims in Alberta are related to snow and ice. Property owners and homeowners are particularly vulnerable to litigation, where it is only necessary to prove negligence. In the case of cities and municipalities gross negligence must be proven.

For a business owner, each slip and fall incident may mean instant costs out of pocket as well as the potential for increased insurance fees over time.

Overall, snowmelt systems are one of the few project-adders that can quickly enhance savings over the life of the project.

Table 1 Hospitalizations related to falls on ice, Canada, 2016–2017

Credit: Table 1 courtesy CIHI

Credit: Data courtesy CIHI

Common snowmelt applications

Sidewalks. Convenient and more inviting to passerby, sidewalk snowmelts can increase business and decrease liability. Customers are more likely to shop stores with clear sidewalks, free from ice and snow and chemicals.

Car washes. Water is always present in car washes. Using snowmelt, property owners can keep car washes open and ice-free. The control strategy for car washes is simple. Either air temperature or slab temperature is monitored. If the temperature of the slab or the air drops below 35°F, the system is activated. When temperatures exceed 35°F, the system is disabled.

Helipads. Hospital helipads are excellent examples of what snowmelt can do. With space becoming more precious, many hospitals are forced to install helipads on building roofs. These rooftop helipads can become extremely dangerous when coated with ice and snow. Snowmelt systems keep them care, not causing it.

Parking garage ramps. Snowmelt systems ensure parking garage ramps. One note of caution: be sure to place sensors for these controls where they can detect snowfall, or precipitation and temperature.

Loading docks. Moving goods is important work, even during winter months. Large area “hot pads.” Instead of melting an entire area, which can be too large and cost prohibitive, smaller areas are melted where snow can be deposited. This technique is often used for airport runways and large parking lots. Typically, tubing for hot pad slabs is spaced at 4- to 6-in. OC to accommodate a large amount of snow. Remember, snow from a runway or parking lot will be collected and deposited on the pad. It’s not uncommon to have a hot pad of perhaps 30 ft. by 30 ft. with snow piled 4- to 6-ft. high. Hot pads are usually operated manually and activated whenever the need arises.

Stairs. Of course, stairs can be dangerous. With snowmelt systems in place, pedestrians can use steps safely. The spacing of tubes for stairs varies according to application, but they’re usually installed with two lengths of tubing in the tread and one in the riser.

Hospital entrances. Because they are usually considered Class III systems, tube spacing for hospital entrance ramps are usually set closely at 6-in. OC. Further, these systems are idled, or operated at a reduced output, to decrease system lag time. When sensors detect precipitation, the system is then operated at full output.

Bob Rudman is commercial products manager with Milwaukee Valve.

Get the flow and location right

Depending on the application, check valves can n get a bad rap. Blame can include problems such ch as water hammer, vibration, reverse flow, leakage, p or component wear and damage – all of which are g harmful to downstream systems. However, the real harmful to downstream syst tem ms. How cause of these problems usually stems from poor sizing cause of these problems usually stem cause of these problems us zing and selecting of the check valve for the application. valve for thand selecting of the check . Most check valves are selected on line size and the desire for the largest Cv available. Swing checks require a minimum rate of flow for the valve to function. If the flow is not sufficient to hold the disc in a full open and stable position, the disc and associated internal parts will be in a constant state of motion (wobble). Insufficient flow results in premature wear, noisy operation, and vibration. The solution to this problem is selecting a line size that produces sufficient flow. A general rule of thumb for water systems is to maintain a minimum of 7.5 ft./sec. flow rate. If the system struggles to maintain that flow rate, it is sometimes recommended that the line size be reduced. In piping systems containing other types of fluids, the flow requirements vary with the specific gravity of the media. Formula 1 can be used to approximate the minimum flow rates.

Most check valve on e size and tline h l t Cv availabl rate of flow flow is no full open a associated in of motion (state wear, noisy premature

Th he e solution em is selectto this probl sufficientflowAgeneralru

Quick work makes for happy customers customers

All check valves should be installed All check valve All check val in a location that has smooth and n tin a locatio laminar flow conditions. The following w laminar flow general rules exist for check valve al rgener installations: talins

1) ) If installing downstream of I a reciprocating pump or other rea turbulence-inducing device rbtur (elbow, tee, etc.): bow(el

Swing Type: Swing Type: Locate the valve a minimum of ocaLo 10-12 diameters downstream of the device. 10-12 diameters dow 10-12 diameters do Silent Type: Locate the valve a minimum of 4-5 diameters downstream of the device.

2) If pipe fittings, elbows, reductions, etc. are downstream of the valve:

Swing Type: Locate the elbow a minimum of 5-7 diameters downstream of the valve.

Silent Type: Locate the elbow a minimum of 2-3 diameters downstream of the valve. the 3

Formula 1 Flowmin (ft./sec.) = 60 V

3/lb.)

Silent check valves have slightly different flow requirements. Sile Spring-loaded silent check valves are designed to provide a Sp cracking pressure of 0.5 psi and to fully open at a 4 ft./sec. cra flow velocity. flow

By Marty Silverman

HOW HOW NOT TO NOT TO BREAK BREAK YOUR YOUR STUFF STUFF

Let’s face it, drain cleaning is plenty hard enough without having to deal with equipment failures. When a drain cleaning machine breaks on the job it can be dangerous, expensive, and an enormous waste of your time.

During the 90 years that General has been in business, we’ve noticed that some contractors suffer far less equipment failures than others. So, what’s their secret?

It’s pretty simple really. Contractors who are patient and careful on the job, and who practice preventive maintenance after every job, tend to break their stuff less often. Funny how that happens. In addition, we find that investing in more durable equipment pays off in longevity. Common sense, right? And there’s more: contractors who break their stuff less tend to make better decisions and have better work habits on the job. Let’s talk about practical things you can do every day to prolong the life of the most common drain cleaning equipment being used in the field.

CARING AND FEEDING OF YOUR SNAKE

One of the most common drain cleaning tools is the drum style cable, or snake machine. We’ve met contractors who have used this style of machine every day for a decade and never broken a cable. What’s their secret? First, they don’t force the cable down the drain, they let the rotation of the cable do the work. They use it like a drill − not a battering ram. Also, after every job they drain the water out of the drum and then spray or pour lubricant into the drum and rotate it for a minute so the oil becomes evenly distributed on the cable. What kills cables fastest? Rust, acid and strong bases. Water is everywhere in a sewer and your customer probably poured Drano or some other corrosive substance down the pipes before you arrived. All of these products can weaken the molecular structure of your cables and make them more likely to kink or break. Always use a lubricant on your cable after a job to preserve and protect it.

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