Radiant Floor Expert	Hydronic Circulators
Solar Expert	Expansion Tank Sizing
Residential Steam Systems	Air Separators
Hydronic Rules of Thumb	Determine Pump Flow
Automatic Flow Limiting Valves	Making Face Time For Engineers
Test Your Hydronics IQ	Integrated Residential Heating Controls

Radiant Floor Expert

With the current frenzy over "green" products lately, I thought I would give some well deserved credit to a product that really stands out in the "green" market. That product is nothing more than hydronic radiant floors. That’s right, no cutting edge technology, no sexy gimmick, just a well designed and installed hydronic radiant floor. In this article I want to talk about what it means to be a “green” product, at least in my eyes, and also explain why hydronic radiant is quite possibly one of the greenest products available.

When we think of HVAC systems and the "green," eco-friendly options we have to choose from, we quite often think of geothermal systems, solar heating, condensing boilers, VFD controlled pumps and fans and many other highly efficient products. But what is truly important to me is not the device itself, but rather the way you apply it to an actual system. For example, if you run a condensing boiler in a system with a return above 130 F, you will not benefit from the efficiency capabilities. What needs to be looked at when thinking "green," is not just a single device, but the system as a whole. Hydronic radiant floor systems have many aspects that can contribute to the overall system efficiency. These aspects are what allow the so-called “green” products shine. It is not surprising then, to see why Frank Lloyd Wright, known for his "Organic Architecture," helped to popularize radiant floor heating in the 1940’s.

A radiant system works by sending hot water through tubing in the floor, which heats the floor surface to 72-85 F. Forced air systems heat air to around 120 – 140 F and circulate it through duct work. The hot air then enters the space and keeps the air temperature around 72 F. A common misconception is that heat rises, which is incorrect because heat goes from hot to cold, in any direction. What is important here is that hot air rises, not just heat. So, when you heat air, like in a forced air system, the hot air will rise to the top of the building, away from the occupants. Radiant floors do not work in this way. Radiant floors transfer heat to the objects and people in the space. This allows for a lower design indoor air temperature, usually 68 F. When compared to a forced air system, a typical residential system will be about 10-30% more efficient, while a commercial hanger or warehouse can see savings up to 60%.

The next aspect we need to look at is supply water temperature. A typical in-slab or sandwich style radiant installation will require about 120 F supply water temperature, on a design day. This is worth mentioning because the low water temperature is what allows a condensing boiler to get its high efficiency. Even a non-condensing boiler will produce better overall system efficiencies if properly designed with a mixing control. Geothermal systems that have a limit of 130 F supply water temperature can be utilized 100% of the time on a low temperature system. The key here is that the radiant floor system is what allowed the heat sources to be highly efficient, not the other way around.

Another great quality of radiant floors is the ease in which they are zoned, much easier than with forced air systems. Each room in a house or building can easily be separated in a radiant floor system. This allows for different temperature settings and the ability to turn down spaces that are not commonly occupied. When you can more easily control your system and send the heat to where you need it, you can save more on your operating costs.

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Solar Expert

Let the Sun Shine In

Four major things motivated my topic this month:

1. The rising costs of fossil fuels;
2. My personal interest in conserving the environment;
3. Tax time; and
4. Spring.

All of our budgets are being stretched by the rising costs of fossil fuels. There are many reasons for this, including geopolitical events like the nationalization of fossil fuel companies in Russia, Venezuela and Bolivia, and conflicts in the Middle East. Earth has a limited supply of easily (inexpensively) extracted fossil fuels, and increasing worldwide demand. In particular, we are no longer the only big customer on the world market. Even at our current, historically high consumption levels, both India and China are challenging the U.S. as having the biggest demand and market for fuel. Alternative energy sources, like solar power can help reduce our dependence on foreign oil.

As easily extracted fossil fuels become less abundant, we have to find "new" reserves. Those new sources are often in ecologically sensitive areas, like the Alaskan wilderness, and offshore. The risk of environmental accidents like those causes by the Exxon Valdez could have an impact on parts of the world that can never recover. Consumption is just half of the issue: what you don't burn, you don't pollute the atmosphere with. More and more experts are agreeing that global warming is caused by human impact on the earth, including emission gasses. Solar energy panels emit no harmful byproducts to the environment.

When we were kids, April was known as the month with showers. As adults, it is known as the month we give a substantial part of the money we have earned back to the government. The good news is that alternative energy sources are supported by Federal and local incentives in the form of tax rebates. Residential projects currently offer 25% of the project cost as a rebate. Commercial projects can offer as high as 30% of the installation, unlimited! These incentives significantly shorten the payback schedule for your solar installations.

Spring, glorious Spring, when we see the sun again in Chicago. Our long winter is coming to an end, and we are reminded of why anyone would want to live here. The sun is a resource that we appreciate because it provides light, lifts our spirits, make us warm, and makes our plants grow. It can also help reduce our energy bills.

Using the energy from the sun is not a new concept, but many things have changed since the 70's when the first energy crunch hit. Solar collectors have improved, controls have improved, and our manufacturers and installers have had years to refine and perfect their installations.

How much energy is available from the sun? There is something called the solar constant, which refers to the approximately 440 BTU/hr/sq. ft. of energy generated by the sun that could potentially reach the earth. Of that potential energy, 30 to 60% is lost in the journey, and 170 to 315 BTU/hr/sq. ft. eventually reaches the surface. Here in Illinois, we receive 1260 to 1575 BTU/sq. ft./Day of energy from the sun. For optimum output, panels should be installed at a 45 degree angle and face South. Optimum output from a panel is roughly 220 BTU/hr/sq. ft. To absorb or collect this energy, there are several different panel or collector styles available. They range in design from photovoltaic, to tubes painted black with parabolic mirrors focusing on them, to flat panels, to vacuum tube collectors. All of these styles of collectors have different outputs per sq. ft. and different limitations to their installation details. The more efficient the panel, the more energy it absorbs, and the less it reflects. In addition, different panels may operate better for example, on a cloudy day, than others.

In the hydronic heating and plumbing industry, we can easily use panels that are hydronic in nature. We circulate a glycol solution through the panel, and the fluid absorbs the energy from the solar collector in the form of temperature, and the system pump then carries the energy to where it can do some work. Typical applications for hydronic based solar systems include supplement to comfort heating, domestic hot water production and pool heating. Comfort heating may initially seem the most intuitive application, but winter has the highest energy consumption, and the most adverse solar conditions. For Domestic water applications the panels are typically sized for 60% of the total load to insure that there is always a heat sink for the energy. Of all the applications, pool heating may make the most sense of all since we use our pools in the summer when the solar conditions are optimum. A rule of thumb for sizing pool systems is that you use enough solar panels to cover ½ of the surface of the pool.

This is just the tip of the iceberg, so to speak. Look for upcoming solar seminars from Bornquist, and from our local distributors. Learn about solar energy, how we can reduce our impact on the environment, reduce our energy bills and reduce our dependence on foreign oil. Solar systems, like those from Viessmann, represent practical alternative energy technology that is available today.

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Residential Steam Systems

Not all hydronic heating systems are water or glycol based. In this area, and on the East Coast, there are still a fair number of steam systems. Many of these systems are residential, and while they are not being designed and installed for new construction, they still represent an important niche in the hydronic market. Just because steam is thought of as an old technology doesn't mean steam systems can't operate efficiently.

Steam systems are generally not installed in new residential construction because they require more maintenance than water systems, and have a reputation for being more difficult to control than water based systems. While it is true that steam systems require regular maintenance, and are generally less efficient on the gas side than water systems, they also use significantly less electricity than water systems because they require no distribution pump(s), and gravity systems have no electrical requirement except for the burner and boiler controls. Properly maintained and controlled steam heating systems can be made to operate near the overall system efficiency of high temperature, set-point controlled water based systems.

Steam systems operate by boiling water, and when the water turns from liquid to vapor, it wants to expand. One pound of steam occupies roughly 1,787 times the volume of one pound of water at 0 PSI. The piping in the system contains this expansion and pressure is created. Like water, steam goes from high pressure to low pressure, and this differential pressure between the boiler and atmosphere (or vacuum pump) drives the "circulation", or distribution of steam through the system. Steam cannot move anywhere unless the air that was there is removed from the system! Venting is therefore responsible for the rate and path of steam distribution. Vents must be chosen for capacity, application and working pressure. Adjustable vents can be used to "balance" steam systems and ensure even distribution so a system isn't satisfied in one area and starved in another. Thermostatic vents mounted on zone valves, like those for Danfoss can be used to zone steam systems and control overheating in one-pipe steam systems.

The energy in steam comes from two components: sensible, and latent heat. Sensible heat is energy that relates to a change in temperature, and it takes 1 BTU to heat 1 lb. of water 1 degree F. Latent heat is the energy that changes the state of the fluid from liquid (water) to vapor (steam). Steam tables tell us information like the ratio of latent heat to sensible heat for steam at any given pressure. For example, one pound of 2 PSI Steam contains 187 BTU sensible heat, and 966 BTU of latent heat, with a temperature of 222 F. The lower the steam pressure, the greater it's ratio of latent heat to sensible heat. Steam does work in heating a system when it condenses, and gives off latent heat. After it has condensed, it is still the same temperature as it was at the pressure of the steam at that point. If steam is not contained without condensing first, the latent heat is wasted up the stack. It is the job of the steam trap to distinguish steam from air (by temperature), and steam from condensate (by state) and keep it in the heat transfer device (radiator or heat exchanger) until it has done it’s work and condensed. Companies like Hoffman manufacture several different styles of traps (thermostatic, float & thermostatic, thermo-disc, bucket and other specialty styles), and it is important that traps are selected properly, not only for load and working pressure, but also for application.

When steam condenses, it "shrinks" in size (also roughly 1,787 times) and a vacuum could be pulled if it weren’t for a device called a vacuum breaker. The vacuum breaker prevents the condensate from “hanging up” in the terminal unit. If condensate is left in the terminal unit, noise often results from water hammer, and flashing.

In order to enhance efficiency, water based system can operate on "outdoor reset" when the water temperature of the system varies in relation to the outdoor air temperature. Steam boilers can also operate using the principal of outdoor reset, but rather than varying temperature, controls from manufacturers like tekmar vary the timing of the firing cycle in relation to outdoor air temperature. Steam reset controls enhance heating system efficiency by preventing "short-cycling" of the boiler, and reducing the tendency of steam systems to overheat under light-load conditions.

Most steam systems bear the signature of those that have designed and worked on them. Unfortunately, much of the knowledge that goes into the design of steam systems is being lost to time. Luckily, there places like Bell & Gossett’s Little Red Schoolhouse that offer you the opportunity to learn about steam applications, design variations, and maintenance. Call Bornquist and your local stocking wholesaler for the steam specialty equipment and knowledge that can maximize the efficiency and operation of your steam heating application.

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Hydronic Rules of Thumb

Do you know enough to be dangerous?

True or False: Hydronic heating systems offer the maximum amount of comfort and efficiency possible to their owners. The answer, of course, is False! What is True, is that properly designed and installed hydronic systems offer the maximum amount of comfort and efficiency. Hydronic or otherwise, improperly designed systems have the same problems: hot and cold areas, large temperature swings, and inefficient operation. For over the fifty years, the ultimate resource for hydronic design and equipment has been Bell & Gossett. With over 60,000 graduates, The Little Red School House, at the B&G factory in Morton Grove, has literally educated our industry, and all at no charge!

Visit your local stocking B&G Wholesaler and learn to properly design hydronic heating systems. Learn about Primary–Secondary pumping, Zoning Made Easy, Flow and Head Loss Calculations, Air Control, and Point of No Pressure Change to name a few. Learn to design and install the most comfortable, most efficient heating system available.

Before you get the chance to attend a class, here are ten simple rules of thumb for designing hydronic systems:

1. PSI x 2.31 = feet of head (TDH)
2. GPM x Delta T x 500 = BTU/hour
3. Pressure Drop for piping system = Linear Feet of Longest Circuit x .06
4. Proper flow for boiler in GPM = Output BTU/hr. divided by 10,000
5. Static Height in feet / 2.31 + 4 PSI = Proper fill pressure
6. Maximum Capacity
   • 1/2" Pipe = 1.3 GPM = 13,000 BTU/hr.
   • 3/4" Pipe = 3.5 GPM = 35,000 BTU/hr.
   • 1" Pipe = 7.5 GPM = 75,000 BTU/hr.
   • 1-1/4" Pipe = 12 GPM = 120,000 BTU/hr.
   • 1-1/2" Pipe = 20 GPM = 200,000 BTU/hr.
   • 2" Pipe = 45 GPM = 450,000 BTU/hr.
7. Maximum output radiant floor = 35 BTU / square foot
8. Typical output snowmelt system = 125 BTU / square foot
9. Estimate for heat loss of New Building = 35 BTU / square foot
10. Estimate for heat loss of Old Building = 50 BTU / square foot

Visit your local B&G Stocking Wholesaler to be enrolled in a Little Red Schoolhouse class, for design or maintenance.

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Hydronic Circulators

Don't Just "Go with the Flow"

Most modern hydronic heating systems use circulating pumps to move water through the piping system, to distribute the energy in the water to the radiation that heats the space. In previous articles, we have discussed one of the formulas we use most often when evaluating and designing hydronic heating systems: BTU/hr = GPM x Delta T x 500. This formula gives us a way of calculating the proper flow to deliver heat to a system. We have also discussed head loss calculations and means of estimating head losses. What we haven’t discussed is why it is important to have the correct flow?

Unfortunately, pumps don't know how much they are supposed to pump. They provide as much flow as the system will accept, until friction losses limit their capacity. With constant speed pumps, that can be anywhere along the pump curve.

To understand the importance of proper flow, it is important to understand a little about how the emitters work. After a designer has done a heat loss calculation, they must selects radiation, and they should specify three pieces of information: Output (BTU/hr.), Supply Temperature, and Differential Temperature. Then, using the formula above, design flow is determined. What happens then if the flow is wrong?

If the flow is too low, the differential temperature across the emitter is too large, and the average temperature of the emitter can be too low to provide enough heat for the space. Worse-case, the flow could be so low that it would be “laminar”, or without turbulence and be unable to give off much heat.

There are also problems associated with flow being too high. If the fluid velocity is above 8 ft./sec. or so, noise and erosion can be an issue. If the delta T across the system is too short, the average temperature of the radiation will be above what the designer expected, and the space could overheat, and/or cycle excessively. When a pump is providing too much flow, it is using more energy than it needs to.

The inefficiencies created by incorrect flow can go back to the boiler plant where, as we have discussed in earlier articles, boiler efficiency is tied to return water temperature, and combustion efficiency is affected by firing cycle time. Flow sensitive boilers can be harmed, or be unable to sustain firing without adequate flow. The “packaged” pump that comes with many boilers may, or may not be correctly sized for the actual piping arrangement on the job.

Residential circulators are often arbitrarily selected, and “one size fits all” in nature. It is important to properly select your circulators, and if possible, verify that the flow is correct. Some pump manufacturers are able to provide multi-speed, and variable speed pumps that can be hard-set for a discrete speed, or controlled to a process variable to maintain proper flow. Variable speed pumps can even be used for injection mixing to provide for setpoint control, and outdoor reset.

Historically, one of the appeals of hydronic heating systems is their forgiving nature. That is partly because if people got enough heat, they were happy. This forgiving nature often leads to heating systems with oversized components and inefficient operation. Now, with rising heating costs, systems are designed to maximize both comfort and efficiency. Properly sized and controlled circulators which are individually selected for their application and location in the system play a key role in attaining these goals.

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Expansion Tank Sizing

Losing your marbles? Are air problems getting you down? The details surrounding expansion tank sizing and location, air separation sizing and location, and fill pressure result in more problems and seem to be shrouded in more mystery than all others I have run into combined. Here are the guidelines you need to do them properly:

Expansion Tank Sizing: Expansion tanks are placed in hydronic heating systems to absorb the increase in water volume as the water in the system is heated. The tank must be big enough to allow the water to expand without increasing the system pressure beyond the relief valve setting. Actually, it is wise to allow for ten percent below the relief valve setting, because many valves will begin to relieve at ten percent below their rated pressure. So, a 30 PSI valve may actually begin to lift at 27 PSI. You need five pieces of information to size the tank: 1.) System Volume, 2.) Fill Pressure, 3.) Relief Valve setting, 4.) Fill Temperature, and 5.) Design Temperature.

1. System volume refers to the amount of water in the system. The expansion volume is directly related to the system volume. In an existing system, volume can be established by draining it and measuring what comes out. The volume of a new system is calculated by an Engineer using the lengths of pipe, their lengths, and the volume of the boiler, and ½ of the tank volume. Below, for your reference, is a list of the linear volume of typical pipe sizes: ½” = .1 gal, ¾” = .2 gal, 1” = .3 gal, 1-1/4” = .4 gal, 1-1/2” = .5 gal, 2” = .6 gal. Consult the boiler manufacturer for the volume of the boiler in the system.
2. Fill pressure into a hydronic heating and/or cooling system should be set so the cold pressure at the top of the system should be a minimum of 4 PSI. Most of the time, make-up is at the bottom, so your PRV should be set for the height of the system, converted to PSI plus four. The conversion feet to PSI is to divide the height of the system in feet by 2.31, then add four. That is the cold fill setting for the PRV. If your building is 30 feet tall, divide that by 2.31, and then add four. 13 + 4 = 71 PSI. If the PRV is left at the factory-set 12 PSI you will have problems! The primary reason to have a minimum of 4 PSI at the top of the system is so the air can be properly vented.
3. Relief valve capacity is determined by the boiler manufacturer. A relief valve is typically provided with the boiler, and is sized with the proper pressure and BTU ratings. Many boilers are available with more than one option for relief valves. A replacement valve would be sized for the same pressure setting, and the same or greater BTU rating.
4. Fill temperature in the Chicagoland area is often assumed to be 40F because that is the coldest the water is coming from the city.
5. Design temperature is the maximum temperature of the water in the system. For the purposes of tank sizing, that temperature should be the same as the high-limit setting of the boiler.

The expansion tank should be located, or joined to the system close to the suction side of the pump. This is because the tank is “the point of no pressure change” in the system. That is often misinterpreted as the point at which there is no pressure change at all, but that is incorrect. There should be no pressure change relative to whether the pump is on or not. The pressure should change as a result of the increase in temperature in the system. The properly located tank will assure proper pump operation.

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Air Separators

Hydronic systems, by their very definition, heat or cool using water, or some other heat transfer fluid like glycol. Many of the potential problems in these systems occur when something other than fluids are in the system. One of the most common contaminates is air. This is particularly because water contains air when it comes from the city for fill. The air can be in the form of bubbles, which we can see, and/or entrained air, which cannot always be seen. Another source of air in a system are pockets of air that can’t removed from the system when it is filled. Not using an air separator can cause big problems. They include, but are not limited to: noise, corrosion, "air lock", and even fluctuating pressure changes caused by having more than one "point of no pressure change".

Bell & Gossett and other manufacturers make specialized equipment that is designed to remove both visible and entrained air from the heat transfer fluid. These devices perform with varying degrees of effectiveness, depending upon their design and system conditions, to collect the air then, in combination with various vents and tanks, expel the air from the system or use it as a cushion for the expansion forces in the system.

The first air separators, like the Bell & Gossett IAS (Inline Air Scoop) were little more than "bumps in the pipe". The larger diameter of the fitting slows down the water enough that the air comes out of entrainment and bubbles to the top of the fitting, where it would either leave through an automatic air vent, or enter the compression tank. Those of you who regularly read this column know what style of tank to use depending upon whether the air is vented, or collected. With this style of separator, it is imperative the the “bump” in the fitting is installed on the top! I have seen several instances in the field when the fitting was installed upside down and the effectiveness of the device was severely compromised. Since these devices work based on their ability to slow the water down, it is important that they are not over-pumped. If the flow is too high, the air will simply be carried through the device as if the separator wasn't there.

Since then, the major innovation in residential air separators has been the addition some type of coalescing element in the fluid stream reduction in size, and integration of features. The coalescing element (which often looks like a brush) acts to improve the efficiency of the device in two ways: 1.) the filaments of the brush give the “micro-bubbles” something to cling to until enough of then glob together to form a big enough bubble to release and be removed; and 2.) they create a more uniform velocity across the entire cross-section of the fitting, which allows the separator to be smaller than before. A further refinement is the integration of the automatic air vent into the separator. This last one, however, makes the vent more difficult to be replaced if it fails, and it is the most common component to fail.

Large, commercial air separators work on the same premise as their smaller residential bretheren, and devices like Bell & Gossett’s “Rolairtrol” have tangential connections which swirl the water through them, creating a low pressure area in the center, where the air bubbles separate more readily. Commercial air separators also offer options like removable strainer screens, lifting lug attachments, legs for floor mounting, and internal modifications that use the swirling action to centrifugally separate heavier than water contaminates like sand and collect them in the bowl at the bottom of the vessel where it can easily be blown-down and removed.

In addition to being more readily removable at low velocities and pressures, air is also driven out of entrainment when the water is warmer. Therefore, an air separator located just downstream of the boiler will be more efficient than one located on the cooler return. Used with philosophy of air control, when the separated air is sent to the compression tank, the air separator should be on the suction side of the pump. When used with the philosophy of air removal, the air separator location is not tied to the location of the expansion tank, and it can be located wherever convenient.

There is an air separator in the size and configuration fro your system. Air separators are low maintenance items with no wearing parts unless the vent is integrated. Bell & Gossett design schools at “The Little Red Schoolhouse” discuss the proper application of air separators and other hydronic specialties. Feel free to sign-up for classes at Bornquist, or our stocking wholesalers.

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Automatic Flow Limiting Valve?

What is an Automatic Flow Limiting Valve?

In a hydronic heating system, overflow can cause overheating, since the additional flow will cause additional heat transfer at the coil. The control valve should sense this based on leaving airside temperature of the coil, and modulate to keep the flow rate in line with the required heat transfer rate. This is good, because the valve is doing its job of controlling heat transfer. If flow is less than design, there will usually be sufficient heat transfer in a heating application, due to the large temperature difference between the mean water and mean air temperatures.

While a heating system is quite forgiving, in a chilled water system, flow rates are more critical. Overflowing a coil by 30% does not provide 30% more heat transfer. Since the mean water and mean air temperatures are much closer, the additional flow simply lowers the return water temperature to the chiller. Short differential temperature limit both a chillers efficiency, and output. For this reason, a flow limiting valve may is used to keep the control valve from allowing too much flow to the circuit. As in a heating application, the valve responds to the conditions on the leaving air side of the coil. As the circuit approaches design conditions, the valve may be fully open. Should the water flow increase beyond the design flow, the valve will not react, since it will remain open in order to satisfy the load. The additional flow will not create a significant increase in the rate of heat transfer, and the circuit will be running at flow rates in excess of its needs.

The Automatic Flow Limiting Valve is a device that balances a spring force to the force created by water flow across a designed surface geometry. In other words, the flow enters the valve, moves across a fixed orifice, then moves through openings in a cartridge before leaving the valve. The cartridge is counterbalanced by a spring, which maintains a resistance to flow. As flow increases, the cartridge restricts further.

The valve must be within its operating range. If the pressure differential across the Flow Limiting valve exceeds the spring rating, the valve will no longer modulate, but will “peg” itself in a fully open position until the differential decrease enough to allow the valve to modulate. If the pressure differential across the valve is less than the spring rating, the valve will no longer modulate, but will be “full open” and less than the rated flow can pass through it. There are different spring ranges available for each valve.

Ideally, the control valves should be controlling flow by modulation, and the balance valves should be fully open to flow. Unfortunately, we don’t live in an ideal world. Control valves may not be properly sized for the flow and pressure differential of the coil/circuit. Pumps may be oversized and creating pressure differentials that force the valves open. Coils may become fouled, with significant reductions in heat transfer. Piping the circuits in a direct return manner may force those valves located close to the main pumps to open.

Automatic Flow Limiting Valves are an easy way to keep circuits from overflowing, thus starving other circuits.

Ask your Bornquist salesman if the system you are working on is right for Automatic Flow Limiting Valves. Many systems are better served with manual valve, like the B&G Circuit Setter.

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Determine Pump Flow

How to Determine Pump Flow

All Bell & Gossett Pumps have tappings in the suction and discharge of the pump volutes. These tappings are used for a number of purposes, not the least of which is to help determine how much water is flowing in the system.

The best way to determine flow rate in a centrifugal pump is to use a single pressure gauge connected to both the suction and discharge tappings on the volute. A needle valve or gauge cock must be installed between the gauge and each of the tappings. This will allow the operator to close the discharge needle valve and read the suction pressure of the pump, then close the suction side needle valve and open the discharge side valve to determine the discharge pressure.

Why one gauge? If two pressure gauges are used, one gauge may tend to read pressures on the low side of its tolerances. Another gauge may tend to read on the high side of its tolerances. The combined error between these two gauges may be sufficient to provide a completely erroneous reading of pressure differential. If we use only one gauge however, the error would be consistent in both the suction and discharge reading. Since we are interested in differential, one gauge is better than two.

So how do you determine flow rate from all of the above? With the pump running, open the suction gauge cock and take the pressure reading. Close the gauge cock and open the discharge side gauge cock.. Take the reading from the discharge side. Subtract the suction reading from the discharge reading to find the pressure differential in PSI. Multiply this number by 2.31 and you now know the pressure differential for that pump in feet, TDH, which is what the pump manufacturer uses to publish pump curves.

Take a look at the pump curve for this pump (call Bornquist if you don’t have one). From the nameplate, determine the impeller diameter. Follow the impeller curve until it reaches the pressure differential (in feet) that you have measured. Draw a vertical line straight down to read the GPM.

Naturally, if you have any questions or concerns, give us a call. We’ll be happy to help.

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Test Your Hydronics IQ

I hope that people come to this site every month to pick-up some useful tips and design ideas.  This month I thought it might be fun to test our “Hydronics I.Q.”.  Of course, this is just for fun and there are a variety of styles of questions for your consideration.  Also, I have addressed all of these issues in past articles so regular readers should have an advantage…

 

True or Falsee:

1.) High efficiency boilers are always more efficient than conventional equipment. 

2.) Only manual air vents should be used with standard steel compression tanks.

3.) Pumps in heating systems should be sized to overcome the height of the building. 

4.) A heating system should be drained and the water replaced prior to every heating season. 

5.) The HV in the B&G HV Booster Pump stands for “high velocity”. 

6.) The water in aluminum heat exchanger condensing boilers must be carefully controlled for proper pH levels. 

 

Multiple Choice: 

1.) When sizing solar systems, the solar fraction is defined by;

a.) the amount of time the sun is “out” each day;

b.) The amount of radiant energy that gets to the earths surface where we can use it;

c.) The percentage of load we design the solar array for;

d.) None of the above. 

2.) The pressure fill valve setting on a hydronic system should be calculated as follows;

a.) the set-point on the box;

b.) The static height of the building in feet divided by 2.31, plus 4;

c.) enough so water comes out of the top;

d.) GPM x TDH / 3960 x pump efficiency. 

3.) Properly controlled snowmelt systems cost approximately $ ?.00 / sq. ft. per season to operate;

a.) $8.00;

b.) $.10;

c.) $.85;

d.) Whatever it costs is less than a lawsuit;

e.) Both C and E.  

4.) Properly applying outdoor reset control strategies to conventional boilers saves, on average, what percent of your heating bill?

a.) 5%;

b.) 20%;

c.) 30%;

d.) 50%

e.) 70%. 

5.) When PVC is rated for venting on a boiler, its temperature rating is?

a.) PVC is not rated as a boiler vent material, just for plumbing;

b.) 148 F;

c.) 300 F;

d.) 190 F;

e.) As long as it’s the cheapest way I don’t care;

f.) Both A and B. 

6.)  The proper way to control a radiant floor heating zone is to measure ?

a.) room air temperature;

b.) room floor temperature;

c.) outdoor air temperature;

d.) all of the above;

e.) none of the above, all you need is a hard-set ball valve. 

 

Extra Credit Essay:

1.) In 100 words or less, how does “primary secondary pumping” work and what can you do with it?

 

 Hopefully you had fun answering these questions.  Visit your local stocking distributors and look for one of several factory schools, as well as one of our many local Bornquist sponsored education opportunities.

 

 

 Answers True or False:  1.) F, 2.) T, 3.) F, 4.) F, 5.) F, 6.) T

 Answers Multiple Choice: 1.) C, 2.) B, 3.) C, 4.) C, 5.) F, 6.) D

 

Essay – Primary secondary piping works because water follows the path of least resistance.  The other rule that governs this type of system is “the Law of the Tee”, which states the flow into the T must equal the flow out of the T.  If two piping systems share a short “common pipe” then they can be hydraulically isolated from one another and flow can exist in one independent of the other.  This flow independence allows us to do things like easily zone systems, place loads in series, blend temperatures with mixing valves and injection pumps, and protect boilers from low flow and low temperature returns. 

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Making Face Time For Engineers by Jim Camillo

"We've been located in this building since the mid-1960s, although we’ve expanded several times since then," Mike Hultgren, Bornquist Inc. president, says when asked about the company's history of residences. On the surface, this statement makes it clear that Bornquist has planted deep roots in the HVAC, plumbing and other industries it serves from its headquarters on Chicago's far northwest side. Further enhancing the firm's reputation are the countless plaques and awards on the office hallways.

And yet, after visiting with the Bornquist staff, one comes to realize the (unintentional) irony of the statement — due to the fact that Bornquist's priority is to have its key staff members away from the office and out meeting face-to-face with engineers (and other plumbing/HVAC industry clients) whenever possible.

"This is a people business, first and foremost. There’s no substitute for meeting face to face with the customer," Hultgren says matter-of-factly on multiple occasions during my visit. "At the end of the day, we’re all about our customers and creating more value for them."

Here To Learn and Serve

For many years, Bornquist has been known for its engineering excellence, which it offers as a way to generate more volume for its vendors. The company has a fourperson sales engineering staff, which helps contribute to the firm's success at selling specified and engineered products. These staff members make up part of Bornquist's outside sales department, which totals 20 people.

Hultgren says that the number of Bornquist salespeople that are graduate engineers continues to increase. Some also have professional engineering licenses, which the company encourages—not only because it's good for the company, but also because it's good for the individual.

In addition, several Bornquist employees are heavily involved with local trade associations, such as the American Society of Plumbing Engineers (ASPE), American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE), American Society of Sanitary Engineering (ASSE), Radiant Panel Association (RPA) and Refrigeration Service Engineers Society (RSES). "We have had our employees serve as local chapter officers in most of these organizations. We’re very proud of that," says Hultgren.

With the exception of Kaulas, all of the engineering sales staff in the Chicago office spent three months at The Little Red Schoolhouse (LRS) shortly after joining Bornquist. The schoolhouse is an intensive training school run by Bell & Gossett and located in Morton Grove, IL. While attending this school, students learn the ins and outs of pumping/piping systems, steam systems, heat transfer, controls and a number of other system-related subjects.

"During that three-month training, you develop relationships by living with others from various rep firms nationally and internationally," says Dave Everhart, who attended the LRS in 1988. He has spent 19 years with Bornquist and is HVAC sales manager. "You must practice developing relationships, just like you practice the technical knowledge aspects. The foundation of serving our customers comes from that."

After leaving the school, the Bornquist employee then learns the "nitty-gritty" of the plumbing/HVAC industries by working with the service personnel and take-off/ quotation department, traveling with salespeople and attending all training programs offered by other manufacturers Bornquist represents. Only then will the employee be allowed to answer the phones and address customer questions.

We have no problem sending our entire staff to training in order to keep them up to date. There’s quite a cost for this, but the results are worth it. After all, we need to be the experts at all levels of the company," Hultgren says. "A person spends several years as an inside sales person, getting to know the product, the applications, and the customers before we move them to outside sales, because we don’t want to put someone on the street who isn't an expert."

"All inside sales people are proficient in what they do, but they also know what they don't know and when they need to turn it over to the outside people."

"Employees are trained as system specialists in two ways. The first is having a complete system-wide view of a project. "We're never looking at a stand-alone product; everything leads to something else. This gives us the ability to help our clients with everything from boilers to pumps to fan coils to water heaters to variable speed operations, and so on. That’s helpful to engineers because we’re able to go in and say, 'this has an impact on that, and we can analyze what that impact will be.'"

The second aspect of system specialty is related to how Bornquist actually sells products. "It's a complex sales system, very specific to the local markets. Even though we've been doing it a long time, and we think we do it well, we're always looking to improve our value to the engineer, contractor, wholesaler and owner," notes Hultgren, who has been in the industry since 1978 and with Bornquist since 1983.

"The unique thing we bring is onesource responsibility—we sell systems," says John Berg, CEO. "Engineers prefer to look to one person to be that point of contact.

"We're unique in terms of our system knowledge—how we approach the problems engineers face," explains Vice President Eric Urbaniac, who has 37 year' experience in the plumbing industry, the last 23 as a Bornquist employee. "We know a little more about the systems that our products go into so that we’re able to advise the customer beyond the simple nuts and bolts of a pump, for example."

According to Hultgren, Bornquist understands the need for an engineer to design projects based on several key criteria — including how a system works both today and in the future, good cost-to-value relationship (to justify the design), system efficiencies, serviceability and cost/payback timeline.

"All of these items are important to an engineer when deciding on a design and specifying specific manufacturers' products," says Hultgren. "We try to conserve an engineer's time by selecting and sizing the proper equipment with the given set of conditions and by providing options. The product lines we represent have helped us take a big-picture look in order to provide the engineer with the best possible choices."

Because the Chicago staff has a smaller geographical territory than its East Moline, IL, counterpart, it can "layer" its sales coverage and focus on types of customers. For example, a separate salesperson might call on mechanical engineers and plumbing engineers in the same geographical area, but each effort supports the other efforts. “We never look at sales in any single area as a vacuum. Each and every sales call has an impact on the total market, not just one part of it," says Hultgren.

"There's a real partnership between the engineer and our engineering sales staff," says Dave Bernholdt, sales manager of the plumbing division. "Our engineers help them on the design-build side of the job, and we help everyone work together as a team at all levels of the project to provide the best product support in the marketplace."

Engineers need the information Bornquist provides to be accurate every time, Hultgren says. The firm also knows that engineers work with a lot of time constraints and that saving time means saving money.

"We can submit data electronically or by paper, whichever the customer prefers. But it can all be done very quickly," says Hultgren. "We're able to process submittals electronically and within two days get them back to our customer because we have two people who are dedicated entirely to doing that," adds Dave Everhart.

"We get them any support documentation, such as specs and CADD details, that they need for product selection," says Dan Watkins. "We also help with any designs outside of what they’d normally do. For example, some engineers are not familiar with radiant floors, so we'll walk them through a design and give them some rules of thumb on the typical things that go into a radiant system. It's a soft-sell process. The engineers know that they can come to us for support later on because we were involved in the design process, and we stand by what we do."

To further benefit their engineer clients, several years ago Bornquist took all of the specifications for all of the manufacturers' products they represent and put them in CSI Format and posted them on the Bornquist Web site. "Specifying engineers want this standardized type of format and they want it easily accessible," says Urbaniec. "Our Web site also has isometric drawings of the products and systems we represent, as well as specific password-entry pages for the engineer, contractor and wholesaler."

At the same time," notes Hultgren, "if the product is oversized, we call the engineer and tell them that the model they called for is beyond capacity for what is needed. They appreciate our follow-up."

Another way Bornquist helps engineers is by fabricating pumps and other equipment to ensure delivery of specified products to the installing contractor in a timely manner. Hultgren explains. "We can often get a stalled job moving forward very quickly, in just a few hours. This again helps the customer know that if they specify our products, they’re getting the backup they want."

As the project proceeds, Bornquist staff members are always there to provide recommendations. "We must be able to quickly determine what that building needs, and sometimes we haven't seen any drawings," says Everhart. "Or a client might send an incomplete set of drawings out to the field to our plan and spec department to do an estimate." Often, before the final version of the drawings are done, Everhart says, the engineer will ask Bornquist's staff to come in and look at the drawing, specifically seeking their opinion of details like the piping arrangement, sensor locations for variable speed applications, condensing vs. non-condensing boiler suggestions, air separator location, etc.

"Whenever a job isn’t running the way the engineer expected, he knows he can come to their salesman at Bornquist and be confident we'll look at the job, help figure out the problem and resolve it.

Everhart notes that they also get general and application questions about products Bornquist doesn't even represent. "In those cases, we'll either provide info or give the name of someone who can help them get their answer."

"In a nutshell, we provide key information. Engineers are always going to have questions and they look to us to provide answers," says Urbaniec. Hultgren points out that Bornquist is not one to overlook contractors when it comes to engineering design. "They do a lot of design work, and there are many cases where the contractor and engineers are working together."

As if all of the above wasn't enough, Bornquist also runs technical schools at various locations in its market areas for consulting engineers, chief engineers, contractors and wholesalers. "We do more technical schools, presentations and seminars than ever. We provide Lunch & Learn seminars at the engineers' offices, in-house seminars here, seminars for association meetings and seminars at places like the Metropolitan Club on the 67th floor of the Sears Tower. The L&Ls provide designbased education and focus on solutions to engineers' problems."

Current/Future Challenges/Opportunities

Currently, the HVAC division accounts for about 75% of sales, although Hultgren says that company growth is evenly matched between HVAC and plumbing. "Over the next two years, I expect the growth in plumbing to be significant," Hultgren states. "We have focused on new opportunities in the engineered plumbing-related markets, particularly highly engineered products."

"We’ve taken on products with solid potential in the territory," says Urbaniec. "We won’t take on a line unless we know we can do the right job for that manufacturer," Hultgren adds.

In the last few years, Bornquist has added to its product/application specialists as a way to ensure a product line's success. Hultgren says that, aside from inside to outside sales assignments (which are intentionally kept loose), Bornquist prefers to have teams that change players. "This lets our specialists move from job to job, regardless of who is the salesperson of record for the order. It keeps a company-wide teamwork attitude going."

The challenges Bornquist faces as a company also present important growth and service opportunities: changes in technology, industry consolidation and economics, and new products and design concepts (including Green Design).

"One of the great things about our investment into new technologies is our sales per employee measurement, which has grown significantly since 2001," Hultgren says. "We are a more efficient company, which helps us put new people in the right places and lets our salespeople connect electronically to the offices, leaving them more time to do the important thing—meet with customers."

Industry consolidation and/or manufacturer consolidation has impacted Bornquist, Hultgren admits, but says being a successful rep firm means being committed to always finely tuning its coverage to meet local needs. "Each market is unique, and if blanket rules are applied too often, you can miss your best opportunities. Local reps provide the finely tuned marketing needed to succeed in multiple territories."

Educating engineers about the changing economics of the industry is another growth opportunity, notes Kaulas. "Even though variable speed drives aren't new, the pricing is. Years ago you might not have used the drive because of the cost involved, but the new economies can let you use a drive on almost every application. Another example is brazed plate heat exchangers. The cost of that product has come down so dramatically we want engineers to know it’s costeffective to use them for particular applications."

Everhart says that many products associated with high-efficiency equipment are brand new to the market—and that the engineer may wish to rely on Bornquist’s expertise to properly achieve and apply that efficiency. "LEED (Leadership in Environmental and Energy Design) is primarily an architectural standard, but the mechanical systems are largely influenced by that standard. We help make sure that the job the engineer promised to deliver is a LEED-certified project that will meet the efficiency performance requirements."

Green design is really picking up a lot, according to Dan Watkins. "A lot of engineering firms that never did green before are calling up and saying, 'I have a LEED project but never did one before — can you help?'" To help his clients get up to speed on green design, Watkins is gearing up to take the LEED AP exam later this year.

When I ask the sales engineers to talk about specific LEED projects, Kaulas discusses some Chicago greywater projects he's worked on the past 12 months. "We had a couple jobs where we recycled the water from lavs and showers and reused that water to flush toilets. To my knowledge, that’s the first and only job like that in Chicago. Then we had a couple greywater-harvesting jobs, where we’re taking the rainwater off the roof and using it, in one case, for irrigation, and in another case, for flushing the toilets. And both those jobs were for specifically LEED credits."

Kaulas also pointed out that he never supplied a solar unit water heater for a job until two years ago. "Now we’ve done eight or 10 jobs since then. That aspect has really taken off, and it's going to grow rapidly over the next several years."

Besides presenting technical seminars on energy-efficient products such as solar, water heating, boilers and variable speed drives, Bornquist also focuses on other important LEED-related issues, such as payback time and helping engineer clients obtain points. "How long will it take for something to pay for itself? That's a common question from the engineer, so we help them decide which technology is most appropriate for their project," says Everhart.

"Usually, the engineers are aware of what they need to do to get LEED credits," notes Kaulas. "They’ll tell us what they need in order to achieve a certain number of points within the building. Our focus is to help them flesh out their ideas and work with them to help them achieve their goals."

One More Thing...

Bornquist sees itself as the face and voice of the manufacturers they represent, and Hultgren says the company always makes sure its employees understand this.

"A few years ago, the president of one of our key manufacturers was playing golf in Chicago. At a par-three hole, the group behind him caught up. In this group was a Chicago-area contractor. Seeing that manufacturers' logo hat, logo golf balls and logo towel, the contractor responded, 'Oh, I see you work for Bornquist.' We like that. It means that we're doing our job as the face and voice of the manufacturer in our territory."

Another way that Bornquist makes sure its employees always keep the customer’s needs in the forefront is through internal promotional sales themes.

"This year, it’s 'Think One.' The theme came from the idea that if we take one more step for the customer, great things can happen. One more sales call, one more introduction within a customer's office, one more product line presented. When you do the math, it leads to a big difference for us," says Hultgren.

"We're listening very hard to our customers and staying with them every step of the way to help them get where they want to go. Our future direction is based on where our customers are going."

Jim Camillo is editor of PM Engineer. He can be reached by phone at 630-694-4011 or email at

Integrated Residential Heating Controls

This article focuses specifically on how integrated controls make a hydronic HVAC system more efficient.

One of the most basic and common systems is a boiler outdoor air reset control. This type of control looks at the outside air temperature and adjusts, or “resets” the boiler water temperature accordingly. The idea here is that is the boiler needs 180°F water on a -10°F outside air day, the system could use a lower water temperature is the outside air is warmer than the -10°F the system was designed for. By running the boiler at a lower water temperature, there are less standby losses in the piping. Reducing the boiler supply water temperature will also help to keep the space from overheating due to getting much hotter water through the radiation device than needed. This type of control is set-up using a reset curve. The reset curve is the ratio of outside air temperature to boiler supply water temperature required.

An integrated control system actually goes one step further by also incorporating indoor feedback. Indoor feedback is looking at the indoor zone air temperatures and using these to automatically adjust the reset curve. What happens a lot of times when not using indoor feedback, we find that it becomes difficult to set-up a perfect reset curve based on outside air temperature alone. When indoor air temperatures are incorporated, the reset curve can automatically be adjusted. So for example, if the control is calculating a boiler supply temperature based on outside air, but the zones are becoming satisfied quicker than expected, the control system can adjust the reset curve down to supply a lower water temperature. This will help to enhance energy savings as well as comfort levels.

There is another aspect of integrated controls that will help to achieve better system efficiency; controlling the boiler cycling. When you have a complete control system that is looking at all of the individual zones, an integrated system can synchronize the zones. All of the zones will follow a common cycle schedule. Let’s say that the control has been set-up to have 20 minute cycles. At the beginning of a cycle, the control system will look at all of the connected zone thermostats and use their indoor feedback to determine the hottest reset water temperature required. The control will then fire the boiler in an attempt to get the system water up to the desired water temperature. Individual zones will open up to allow water to flow if they currently need heat. Zones will shut down at different times based on if they need more or less heat. It is also possible that a zone that does not currently need heat will allow a small amount of water to flow in an attempt to prevent the zone from dropping below set-point. Why not, the boiler is already running for the other zones. The key here is that once the boiler turns off during the cycle, it cannot be turned back on until the next cycle begins.

This may seem a bit odd, but preventing the boiler from short cycling every few minutes will help to improve the overall efficiency of the system. In a system without integrated controls, any thermostat can force the boiler on. So, one zone may have the turned on the boiler and as soon as it shuts off, another zone turns it back on. This would cause major short cycling of the boiler. The reason that short cycling of this nature is such a waste of energy is that every time the boiler turns on, there is a few seconds of running gas just to get the flame established. There is also time spent when the boiler turns off to purge hot flue gases from the venting system. These things combine to waste a lot of energy when boilers are turned on and off. It is much more advantageous to run a boiler for a longer time and then turn off for a longer time. Integrated controls help to do this by synchronizing zones cycles.

This concept of integrated controls can be even more powerful on a system that uses a condensing boiler. Since condensing boilers also typically modulate, they allow for much lower reset water temperatures. Using an integrated control system with a modulating condensing boiler means that you will be able to run the boiler almost constantly by modulating the water temperature to exactly match the heat required by the building. Since the boiler will not be turning on and off as often, just modulating the firing rate, it will be able to achieve a much higher overall efficiency. As you can see, using integrated house controls will allow for much better cycle efficiency of a boiler system. Since the controls are looking at outside air as well as indoor air feedback, the control system can much more accurately create the water temperature that the system needs. More importantly though, the system can synchronize the cycling of the indoor zones to prevent the boiler from excessive on and off cycling. All of these things combined will help to improve the efficiency of your hydronic system.

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