January 2018 Blog

Hays Fluid Controls is proud to announce the details of our attendance at the 2018 AHR Expo (Booth # 1821). This year the AHR Expo will be located in Chicago, Illinois from January 22-24th.

Hays Fluid Controls has been going to the AHR Expo for 20 years and every year we look forward to all it has to offer. The 2018 AHR Expo has announced that this year’s show will account for over 2,000 exhibitors and over 65,000 professionals.

Ultimately, the most exciting part for Hays Fluid Controls is the chance to connect face-to-face and shake hands with new and existing customers. We look forward to showing off our latest equipment, connecting with all prospective customers and educating the public about how we provide superior fluid control solutions.

Hays Fluid Control offers:

  • Automatic Balancing Valves
  • Manual Balancing Valves
  • Mesurflo Characterized Control Valves (MesurfloCCV)
  • WSHP Hose Kits
  • Fan Coil Packages
  • Valve Components and Other HVAC Accessories
  • Low Temperature automatic balancing valves (+15° F to +40° F).
  • Stainless Steel & Bronze automatic balancing valves for marine and process applicationsDon’t miss out on our live demonstrations of our new and outstandingly timeless solutions. Come see us at booth #1821 to learn about the energy savings and comfort that our Mesurflo Balancing Valves can provide building owners. We can’t wait to meet you
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November 2017 Blog

Important considerations for HVAC Load Calculations

In the HVAC industry calculating the Heating/Cooling loads of a building are critical to the overall design of the building. There are many variables that need to be examined to appropriately size the HVAC system. In the past, all variables either could not be measured or were not taken into consideration, and safety factors were applied to compensate for the unknow heating/cooling load. This can cause the system to be over sized, and can cost the building owner additional money in installation and operating costs.   Properly sizing HVAC systems can maintain comfort, humidity levels, and increase energy savings. A better understanding of the principles behind how buildings lose and gain heat can help with discussions between building contractors, and HVAC engineers.

Location of the building is a critical design consideration for Heating/Cooling Loads. For example, the cooling load will be much less for a building in New York City vs. a building in Miami, and vice-versa for the Heating Load. Usually there are two temperatures to design around, the Warm Season Temperature, and Cold Season Temperature. These temperatures represent the coldest winter day and the warmest summer day respectively. Temperature data is collected and shared by ASHRAE for cities around the world, and can be found in ASHRAE Fundamentals Handbook. The Warm and Cold Season Temperatures are a starting point in understanding how much heat is gained or lost by the building due to the outdoor ambient temperature.

Another aspect to look at is how well the building is insulated. A well-insulated building will be able to maintain comfortable temperatures without increasing energy usage. The measurement of how well heat travels through a given material is known at the “U-factor”. The U-factor is the amount of energy that travels through the material per area of material within an hour for every degree difference across that material. The metric system uses the units kWh/m2-C-hr, and the imperial units are Btu/ft2-F-hr, to define the U-factor. Building materials with relatively low U-factors are good insulators, and keep heat from transferring quickly.

The temperature difference used in the U-factor equation is the difference between the indoor design temperature and the outdoor temperature. The outdoor temperature used is one of the seasonal temperatures that was discussed above. The indoor design temperature is set depending on the activities in the building, typically this temperature is 70oF. To find the buildings Cooling Load the Warm Season Temperature is used for the outdoor temperature, while the Heating Load uses the Cold Season Temperature. To find the heat loss through a building wall, ceiling, or floor, the equation     is used. Looking at that equation Heat Loss (Q) is equal to the walls area (A) times the materials (U-Factor) times the change in temperature across that wall.

You can see that heat loss calculations can become complicated quickly because building walls, ceilings, and floors are not usually the same material throughout.  The percentages of materials used can simplify the calculations.  For example, if a wall is 10 feet high by 50 feet long with five, 4’ x 2’ windows, we can assume that 8% of the area for heat loss is the windows and the rest is the normal wall. The same assumption can be made with the make-up of the wall, like if it is 80% insulation and 20% lumber.

Infiltration and exfiltration need to be taken in consideration when calculation heating/cooling loads. This is when air leaves the building through cracks, or forced out via ventilation for air quality purposes.  There are tables found in the ASHRAE Fundamentals Handbook – Chapter 17 that tabulate the building material, whether it’s a widow, door, or even an elevator shaft, and give it an air leakage coefficient. These calculations are usually very complicated and use system software in conjunction with the blower-door test to calculate heat loss rates.

Occupation, activity, and equipment within the building is another variable that need to be taken into consideration. Internal loads can range from computer equipment that needs to be cooled, to people moving in a factory.  These values of heat gain can be found in Chapter 18 of ASHRAE Fundamentals Handbook.

When all the variables for a building are taken into account the Heating/Cooling load for a properly sized HVAC system can be installed. This will keep the building occupants comfortable, while keeping cost and energy usage to a minimum.


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June 2017 Blog

ATC Valves 101
Automatic Temperature Control (ATC) Valves are commonly used in the HVAC industry to maintain a set temperature through the coil of a heating or cooling system. There are three different types of ATC valves, On/Off, Floating, and Modulating, all having different levels of accuracy. All ATC valves have a sensor receiving a temperature signal that will regulate the amount of flow through the valve. The flow is typically controlled by an electric signal or mechanically with hydraulics. Electrically there are two types of devices that receive a signal, rotary actuators, or linear actuators. Rotary actuators typically control butterfly, ball, and plug type valves. Linear actuators typically control globe and diaphragm type valves. With hydraulics, a pressurized fluid determines the position of the valve, these are normally globe and diaphragm type valves. The type of system and control needed  typically determines the type of ATC valve selected.
On/Off ATC valves are typically controlled electronically. There are two set points the valve will operate under, fully open or fully closed. The sensor will detect a difference in the set temperature and the actual temperature and tell the actuator to open. When the set temperature is reached the valve receives a signal from the sensor telling the valve to close. To prevent the valve from constantly opening and closing there is usually a range the actual temperature can be at (above or below) before a signal will be sent to open or close the valve. On/Off ATC valves are often referred to as 2-position Normally Open (NO) or Normally Closed (NC) valves.
Floating ATC valves have more control compared to On/Off ATC valves. Floating ATC valves are controlled electronically but have the ability to open/close slowly, and stay at a point between open and closed. When there is a difference between the set temperature and the actual temperature, a signal from a sensor is sent to the valve controller. The signal received by the controller will determine the valve position. When the set temperature is reached the valve will hold that position. This provides the system with better control of temperature through the coil.
Modulating ATC valves have the most control of temperature through the coil. Modulating ATC valves can either be controlled electrically or mechanically. The temperature differential will be continuously monitored by the sensor. The sensor will give instant feedback to the valve controller to determine its position. Electric Modulating ATC valves typically use a high-resolution controller so the valve can move and be held at any position. For mechanical  Modulating ATC valves, a hydraulic fluid is calibrated to expand or contrast depending on temperature change. This type of controller is used where the system needs to control the flow precisely to regulate the change in temperature across the coil.
The other aspect to decide on Actuators is their mode of operation during the loss of power, Spring Return type versus Non-Spring return type. For protection for the pump and maintenance of the system, ATC valves have a mechanism to keep the valve either to fully open or closed when power is removed from the valve. These valves are referred to as Spring Return ATC valves. The spring will move the actuator fully open or fully closed when there is no power. Depending on the system this option can help keep the heating/cooling fluid from back flowing to the pump, and help ease of maintenance when working on the system. As opposed to the, Non-Spring Return type actuators would normally stay in their last position during power failure.

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May 2017 Blog

Why Perform Hydrostatic Leak Testing?

Hydrostatic Leak Testing is an industry standard for testing components in fluid systems. This test is performed to display defective materials that would not have been previously detected. ASME B31.3[1] requires this testing to ensure tightness, strength, and conformance to maximum allowable working pressure. To make sure Hays conforms to the latest industry standard each valve design is analyzed during and after Hydrostatic Leak Testing.

The Hydrostatic Leak Test can be performed on valves to ensure integrity is maintained throughout the life of the valve. During Hydrostatic Leak Testing, a valve is filled with highly pressurized water for a specific period. This pressure is significantly higher than the design pressure for an added factor of safety. If at any point the valve leaks this is considered a failure. Failures in valves mainly occur at connection points where a seat, seal or weld is located. Many of Hays valve bodies have multiple connections creating potential failure points during the test. It is critical to find failure points to determine if the valve design needs to change.

Hydrostatic testing of valves is generally performed to expose possible leaks during assembly and its capability to with stand the maximum design pressure. Hays follows the procedure outlined in ASME E1003-13[2] Standard Practice for Hydrostatic Leak Testing. The amount of time the pressure is held depends on the size of the valve. Test pressures are held for 1.5 minutes per inch of wall thickness, with a minimum time of 10 minutes and a maximum time of 2 hours. At Hays, for commercial valve bodies, we bring the pressure above the design working pressure called out in our specifications. Then the valve is visually inspected while the pressure is being applied, and after the pressure is released, to determine if any leaking has occurred.

Below is a simplified schematic of the test set up here at Hays (Figure 1). An air driven liquid pump is used to pressurize water inside the valve. Because water is nearly incompressible, there is little energy used by the pump to achieve desired testing pressure. When valve reaches test pressure it is inspected for leaks. After the appropriate amount of time has passed, the pump is turned off and the valve is removed. The water drains back into the supply tank and another valve can be tested.

[1]ASME B31.3 – Process Piping – A Code for Pressure Piping is a conformance standard for piping systems and components in piping systems.

[2]ASME E1003-13 – Standard Practice for Hydrostatic Leak Testing outlines the procedure for pressure testing components in piping systems.

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April 2017 Blog:


Pipe size is a critical aspect in designing a hydronic system for cost, longevity, and noise reduction. The inside pipe diameter should be determined after the optimal flow rate is calculated. The pipe diameter is calculated with a maximum velocity limit. This velocity limit is critical to prevent damages from occurring. For HVAC applications, Hays recommends using maximum velocity of 7 fps for design. Fluid velocity (V) is directly proportional to the fluid flow (Q) by equation 1 (ASHRAE, 2013).

Q =VA                                                                                  (eq. 1)

where                                                                                                                                            Q=Flow, ft3/sec                                                                                                                                         V= Velocity, ft/sec                                                                                                                              A=Area, ft2

Problems can occur when a maximum velocity is not taken in consideration. From the flow equation above, as the flow increases if the pipe area does not increase this will create a higher fluid velocity. Flows at higher velocities can create undesirable noise levels, high erosion levels, and even higher pumping costs.

Noise in piping systems are a result from turbulence, cavitation, release of entrained air, and water hammer (ASHRAE, 2013). The Reynolds Number (Re) is a key indicator when looking at turbulent or laminar flow. Any value when calculating the Reynolds number over 10,000 is considered fully turbulent in that system. The Reynolds number is a dimensionless number found using equation 2 (ASHRAE, 2013). From this equation, the Reynolds Number is directly proportional to the fluid velocity. Any increase in velocity and turbulence increases with it creating unwanted noise.

Re=(DVρ)⁄μ                                                                                (eq.2)

where                                                                                                                                         Re=Reynolds Number, dimensionless                                                                                             D= inside diameter of pipe, ft                                                                                                      ρ=fluid density, ft2                                                                                                                                                                                                                                                      μ= dynamic viscosity, lbm/ft-s

Erosion occurs in hydronic systems by sediment, and water bubbles. Erosion in piping systems at velocities lower than 10 ft/sec. is not substantial. Sediment in the system at high velocities is where erosion transpires at a quick pace. Putting a strainer in piping systems is always a good idea to reduce sediment build up.

Water hammer is another design characteristic to be considered. The water hammer phenomenon is triggered when any moving fluid though a system stops abruptly. Large pressure spikes can be observed when fluid is moving at high velocities. Equation 3 (ASHRAE, 2013) shows that fluid velocity has a direct correlation to the pressure rise in a hydronic system. Keeping the velocity at a reasonable speed can reduce damage during any situation where water hammer occurs.

∆ph=(ρcs V)⁄gc                                                                          (eq.3)

where                                                                                                                                                        ∆ph= Pressure rise caused by water hammer, lbf/ft2                                                                                                                               cs= Velocity of sound in water, ft/sec                                                                                                gc = Gravity constant, ft/sec2

In summary, by properly sizing pipes based on flow through the system will prevent unwanted issues. Below is a chart of recommended pipe sizes given a certain flow rate. Use Hays Velocity Calculator for Pipe Sizing (Hays Fluid Controls, 2016).




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Benefits of Installing Balancing Valves on the Return Side of Coils

Shifting viewpoints on flow controls can cause disagreements where balancing valves should be located in closed loop systems. Many (including us at Hays Fluid Controls) agree that the balancing valves should be placed on the return side, whereas other companies may choose the supply side.

The role of balancing valves are to control the flow rates in each of the buildings branches to deliver the desired flows in low temperature, chilled, or hot water applications. At each heat exchanger the balancing valve is set to provide the desired flow rate to maintain comfort and energy.

The ASHRAE Handbook states that “Water velocity noise is not caused by water but by free air, sharp pressure drops, turbulence, or a combination of these, which in turn cause cavitation or flashing of water into steam.” When comparing the location of installing Mesurflo valves, the one on return side will help in reducing the amount of free air in the coils and hence decrease the potential for noise. Another benefit being thappt you want to balance after the friction loss of the coil not before the loss.

With that in mind, there is not a right or wrong order to place the balancing valves because both location have been proven to be effective. Placing a balancing valve on the supply side will give you satisfactory results, but choosing the return side can be more effective because it can reduce air and noise problems while achieving better heat transfer across the coils. Moreover, the coils can remain fully flooded and there will be less turbulence due to less free air trapped in the coils. Due to several above benefits, Hays highly recommends to install the Balancing Valves on the Return side of the coil whenever possible.

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Naval Bronze

Seawater’s corrosive behavior effects the material used to transport it. Many metals alloys cannot handle the destructive nature, so specific material must be used to provide greater resistance. Selecting the appropriate material can drastically extend the life of the component. Naval Bronze (C83600) is an excellent material choice when handling seawater as the medium.

Naval Bronze is a copper alloy comprised of 85% copper, 5% Tin, 5% Lead, 5% Zinc (85-5-5-5) and a trace of other alloys. The thermal conductivity is very high, which makes it a great option for contact cooling at low temperatures. Copper itself can be very porous, so Tin, Lead, and Zinc all aid in eliminating unwanted porosity issues.  In addition, Tin gives the alloy a high resistance to corrosion and weakness. The higher tensile strength and resistance to cavitation make it an appropriate selection for seawater applications.

C83600 is suitable for industrial C86300-Roundapplication including: bushings, frames, struts, gears, valve stems, cams, and hydraulic cylinder parts. At Hays Fluid Controls, we use the alloy for commercial marine seawater valve applications, which can included luxury yachts, cruise ships, and work boats.

If higher velocities or flow rates are needed for marine applications, 316SS is a great alternative. Naval Bronze and 316SS are both regarded as appropriate material alloys due to their physical material strength using seawater as a medium.

Choosing the correct valve is key to treating seawater systems as a whole. Many systems are chosen based on initial cost, which can require significant maintenance over the life of the valve if not frequently checked. More progressive companies will opt for a better material alloy which may have a higher cost, but will save on maintenance cost and will function reliably. At Hays Fluid Controls we choose Navy Bronze because it has the best of both worlds. The alloy has exceptional decay resistance and function properties in relation to its cost.

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Legionellosis and ASHRAE Standard 188

What is Legionellosis?

Legionellosis refers to two distinct clinical illnesses. There are over 50 species of Legionella, a common aquatic bacterium. When the bacterium Legionella causes pneumonia, the disease is referred to as “Legionnaires” disease (LD). The Centers for Disease Control and Prevention (CDC) estimates that each year there are between 8,000 and 18,000 cases of LD in the United States and more than 10% of these cases are fatal. The Legionella bacterium can be found in natural or man-made water systems, including hot tubs, cooling towers, hot water tanks, and plumbing systems. Legionella prevention is a hot topic right now and will be on the radar of HVAC and plumbing professionals.

Some Measures to Avoid Legionella:

Two main environmental factors will favorably impact the growth of Legionella in a domestic hot water system; Low water temperature and Water stagnation. Measure to avoid:

  • Maintain water temperature at 140°F (the bacterium can survive in a temperature range from 68-122°F and grow in range of 77-108°F)
  • Avoid “Dead Legs” in pipe design (to avoid any areas of stagnation in piping)
  • Use Re-circulation Pumps continuously (to minimize scale and stagnation)
  • Make sure backflow preventers are functioning properly
  • Perform routine maintenance measures

The most obvious way to avoid this situation is to maintain the system at a higher temperature and recirculate the water continuously. A high/low flow mixing valve should be used in storage systems so the tank can be kept at 140°F to prohibit Legionella growth while providing 110°F water to the fixtures. ASHRAE Standard 188 discusses the risk management requirements. Presumably, system designers will be able to refer to this standard of practice to determine if their building water system design and engineering practices should be reviewed or revised.

ASHRAE Standard 188:Legionella-300x300

The purpose of standard 188 is to establish minimum Legionellosis risk management requirements for the design, construction, commissioning, operation, maintenance, repair, replacement, and expansion of new and existing buildings. Standard 188 aims to reduce the risk of Legionellosis through specific measures that identify and subsequently address the risk of Legionella. It specifies certain practices that are responsibility of the owner to initiate and follow through with in order to reduce their own risks. Requirements that are provided to the building owner or designee are included in Section 8 of the standard:

  • Drawing and documents of the actual installation
    • Schematic diagrams of water systems
    • Monitoring and control diagrams of water systems
    • Local, regional, and national code compliance
    • Operating instructions and procedures
    • No-flow and low-flow portions of the piping and building water systems
    • Impact of heat loss from hot water or heat gain by cold water in piping and water system components
  • All water systems shall be balanced, and a balance report for all water systems
  • Detailed instructions for commissioning of all building water systems
    • Procedures for flushing and disinfecting
    • Confirmation that building water system performance meets design performance parameters

This is indeed an extraordinary new requirements for building owners/facility managers – one that will no doubt involve a challenging learning curve. Nevertheless, it gives engineers the opportunity to decide on their own baseline preventive measures for Legionella (i.e. re-circulation, temperature, maintenance, etc.), while leaving it up to building owners to identify and address any further action that should be taken.

For system balancing please refer to our company webpage or contact our customer service at:

Phone: (800) 354-4297

Fax: (704) 922-9595

Email: info@haysfluidcontrols.com


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Hays Fluid Controls Introduces Low Temperature Mesurflo® Automatic Balancing Valves for Glycol Chiller Systems

As markets shift, new products must be designed to meet customer requirements. At Hays Fluid Controls, we pride ourselves in bringing innovation and accessibility to new and improving markets. This month we are excited to announce the website release of our Low Temperature Mesurflo® Automatic Balancing Valves for Glycol Chiller Systems.

The “Gold Standard” for controlling flow is specifically designed for glycol systems operating at temperatures as low as 15°F. Models 2510LT and 2520LT (pictured below) are designed for Websitesupermarket medium temperature display cases and walk-in coolers. Consult factory for other Mesurflo® valve designs with low temperature internal components. Hays’ patented Mesurflo® Automatic Balancing valves are known as the “Gold Standard” because their unique features and benefits make them the ideal solution for controlling flow in Glycol

Mesurflo® offers you these significant benefits:

  • Eliminates the high cost of testing and balancing
  • Additional display cases may be added without affecting the system balance
  • Accuracy provides 99.8% heat transfer
  • Eliminates oscillation, vibration, noise and feed­back in the system
  • Non-clogging design that can be back washed for easy cleaning
  • Maintains proper flow rate for high efficiency of the coil
  • Reduces the number of valves required to balance the system

For those interested in our new products be sure to call our customer series representatives for more information or visit our website at:


Phone: (800) 354-4297

Fax: (704) 922-9595

Email: info@haysfluidcontrols.com

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2016 AHR Expo

arh orlandoHays Fluid Controls is proud to announce the details of our attendance at the 2016 AHR Expo. This year the AHR Expo will be located in Orlando, Florida from January 25-27th. This year we will be including a new booth design which will showcase our exciting product lines.

Hays Fluid Controls has been going to the AHR Expo for over 10 years and every year we look forward to all it has to offer. The 2016 AHR Expo has announced that this year’s show will account for over 2,000 exhibitors and over 60,000 professionals.

Ultimately, the most exciting part for Hays Fluid Controls is the chance to connect face-to-face and shake hands with new and existing customers. We look forward to showing off our latest equipment, connecting with all prospective customers and educating the public about how we provide superior fluid control solutions.

Hays Fluid Control offers:AHR Booth

  • Automatic Balancing Valves
  • Manual Balancing Valves
  • Pressure Independent Control Valves (PICV)
  • WSHP Hose Kits
  • Fan Coil Packages
  • Valve Components and Other HVAC Accessories

Don’t miss out on our live demonstrations of our new and outstandingly timeless solutions. Come see us at booth #2144 to learn about the energy savings and comfort that our Mesurflo Balancing Valves can provide building owners. We can’t wait to meet you!

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