Climate Control

Not everyone is familiar with all the intricacies of HVACR as we are at Parker Sporlan and that’s okay. Whenever you have questions, you can always contact our world class Technical Support team or check Parker.com/Sporlan for in-depth information and guidance. Our Climate Control Blog has many of the answers you need for questions on most topics, so dig in. Below, we’ve answered some of the most frequently asked Thermostatic Expansion Valve (TEV) questions – you’ll find easy answers to your need-to-know questions.

  Where should the TEV external equalizer be installed?

The purpose of the external equalizer is to sense the pressure in the suction line AT THE BULB LOCATION and transmit it to the TEV diaphragm. This usually means installing the external equalizer immediately down stream from the bulb. This ensures the correct pressure is signaled to the TEV. In some situations, this “ideal” location may not be possible. In these cases, an alternate location could be used. However, the pressure at these locations must be nearly identical to the pressure in the line where the bulb is located. In other words, alternative locations are acceptable as long as these pressures are essentially the same as when the system is operating at full load. In the past there has been concern about installing the external equalizer “up-stream” from the bulb. This was due to the possibility of refrigerant leaking past the TEV push rods, passing through the equalizer line and into the suction line, thus falsely influencing the TEV bulb temperature. Today, with Parker Sporlan’s TEV design, this possibility is virtually eliminated.

  Where should the TEV’s bulb be located?

In general, the TEV bulb should be installed on a straight section of horizontal suction line. When the compressor is above the evaporator – Locate the bulb on a straight, horizontal line, pitched slightly down, immediately after it leaves the evaporator. A short trap should follow before the vertical line rises to be connected to the compressor suction. With the line pitched down, any liquid refrigerant and/or oil will pass into the trap, away from the bulb. As the trap fills with oil, the velocity of the refrigerant will carry the trapped oil into the vertical section and be returned to the compressor. When the compressor is below the evaporator – No trap is required after the bulb location, but the line should be pitched slightly down to prevent any liquid refrigerant or oil from being trapped at the bulb location. When several evaporators are installed both below and above the common suction line – Observing the same principles outlined above, the piping should be arranged to prevent the accumulation of oil and/or refrigerant at the bulb location. Also, traps installed in the suction lines of evaporators prevent the refrigerant from one evaporator from entering the suction line of another evaporator.

  Should a Parker Sporlan Thermostatic Expansion Valve (TEV) be adjusted after installation?

Before leaving the factory, a specific superheat setting is made on each and every Parker Sporlan TEV. A standard superheat setting has been established for every size and every thermostatic charge. This standard-setting provides the proper superheat on the average system to which the particular TEV size and charge is likely to be applied. Therefore, in most cases, a superheat adjustment on the job will not be necessary. Parker Sporlan recommends a change in the superheat adjustment only after it has been determined that it is required. Careful measurement of the operating superheat, using the recommended procedure, will establish if a change would be beneficial. To reduce the superheat, turn the adjusting stem COUNTERCLOCKWISE. To increase the superheat, turn the adjusting stem CLOCKWISE. When adjusting the valve, make no more than one turn of the stem at a time and observe the change in superheat closely to prevent over-shooting the desired setting. On adjustable TEVs, Parker Sporlan attempts to position the adjusting stem at the half-way point when it is at the standard-setting. This allows maximum adjustment in both directions. Parker Sporlan supplies a number of OEMs with non-adjustable TEVs. The OEM determines the superheat setting through laboratory testing of the unit. Some of these valves can be converted in the field to adjustable models.

  How can I tell if my TEV is adjustable?

Most of the TEVs listed in Parker Sporlan Catalog 201 or Bulletin 10-10 will be adjustable unless there is an “N” stamped in the valve body as part of the nomenclature (i.e. NSVE-5). Many of the valves made specifically for OEM customers are non-adjustable. One way to tell if a valve is adjustable or non-adjustable is to look at the bottom cap. Adjustable expansion valves will have a threaded joint between the valve body and bottom cap as well as a threaded joint between the bottom cap and a hex seal cap that is removable to expose the adjusting stem. Non-adjustable valves, on the other hand, will generally have only one threaded joint between the valve body and bottom cap. An exception to this rule is a factory adjustable valve with two threaded joints and a smooth, round non-removable seal cap. Many non-adjustable valves can be converted to adjustable by changing the bottom cap assembly. Contact Parker Sporlan’s Technical Support department for more information. They will need all the information you can get from the valve’s markings to assist you. CAUTION: Never attempt to determine if a valve is adjustable by removing the bottom cap assembly unless the system has been pumped down, it could result in serious injury.

  Can I replace the powerhead on my Parker Sporlan TEV and how do I know what to get?

With a few exceptions, most Parker Sporlan thermostatic expansion valves manufactured after 1993 have replaceable thermostatic elements. The exceptions are valves with an “H” before the valve nomenclature (i.e. HSVE-10), the now obsolete Platform valves, and the relatively new HX valve. The Platform and HX valves can be identified by a stainless steel element. The valves with the “H” in the nomenclature have had the elements soldered to the valve body at the customer’s request. Parker Sporlan makes replacement element kits that are available through Authorized Sporlan Wholesalers. The thermostatic elements on Parker Sporlan expansion valves are identified by a series of numbers and letters. The number (i.e. 33, 43, 83, etc.) identifies the element size, while the letters (i.e. VGA, RC, JCP, etc.) identify the refrigerant and thermostatic charge. A replacement element kit can be obtained based on that information. For example, a valve with markings on the element of 83 and VCP100 will require a KT-83-VCP100 element kit. (For more information on element identification, consult Bulletin 210-60.) If markings on the element are no longer legible, contact Parker Sporlan’s Technical Support team for help in selecting a replacement element. They will need all the information available from the valve body, and a description of the application. To completely identify a Parker Sporlan thermostatic element the following information is required:

• Element size number

• Refrigerant Thermostatic charge

• MOP (Maximum Operating Pressure) if other than standard E

• Capillary tubing length

• Bulb size if other than standard

For more information on Thermostatic Expansion Valves (TEVs) download a copy of Bulletin 10-10. For more troubleshooting information download a copy of 12 Solutions for Fixing Common TEV Problems - Form 10-143.

 

HVACR Tech Tip Article contributed by Jason Forshee, application engineer,  Sporlan Division of Parker Hannifin

 

 

 

 

 

Additional HVACR Tech Tips helpful for you: 

HVACR Tech Tip: Basic Troubleshooting Given Three Measurements

HVACR Tech Tip: Principles of Thermostatic Expansion Valves

HVACR Tech Tip: Where Should the TEV External Equalizer Be Installed?

Not everyone is familiar with all the intricacies of HVACR as we are at Parker Sporlan and that’s okay. Whenever you have questions, you can always contact our world class Technical Support team or check Parker.com/Sporlan for in-depth information and guidance. Our Climate Control Blog has many of the answers you need for questions on most topics, so dig in. Below, we’ve answered some of the most frequently asked Thermostatic Expansion Valve (TEV) questions – you’ll find easy answers to your need-to-know questions.

  Where should the TEV external equalizer be installed?

The purpose of the external equalizer is to sense the pressure in the suction line AT THE BULB LOCATION and transmit it to the TEV diaphragm. This usually means installing the external equalizer immediately down stream from the bulb. This ensures the correct pressure is signaled to the TEV. In some situations, this “ideal” location may not be possible. In these cases, an alternate location could be used. However, the pressure at these locations must be nearly identical to the pressure in the line where the bulb is located. In other words, alternative locations are acceptable as long as these pressures are essentially the same as when the system is operating at full load. In the past there has been concern about installing the external equalizer “up-stream” from the bulb. This was due to the possibility of refrigerant leaking past the TEV push rods, passing through the equalizer line and into the suction line, thus falsely influencing the TEV bulb temperature. Today, with Parker Sporlan’s TEV design, this possibility is virtually eliminated.

  Where should the TEV’s bulb be located?

In general, the TEV bulb should be installed on a straight section of horizontal suction line. When the compressor is above the evaporator – Locate the bulb on a straight, horizontal line, pitched slightly down, immediately after it leaves the evaporator. A short trap should follow before the vertical line rises to be connected to the compressor suction. With the line pitched down, any liquid refrigerant and/or oil will pass into the trap, away from the bulb. As the trap fills with oil, the velocity of the refrigerant will carry the trapped oil into the vertical section and be returned to the compressor. When the compressor is below the evaporator – No trap is required after the bulb location, but the line should be pitched slightly down to prevent any liquid refrigerant or oil from being trapped at the bulb location. When several evaporators are installed both below and above the common suction line – Observing the same principles outlined above, the piping should be arranged to prevent the accumulation of oil and/or refrigerant at the bulb location. Also, traps installed in the suction lines of evaporators prevent the refrigerant from one evaporator from entering the suction line of another evaporator.

  Should a Parker Sporlan Thermostatic Expansion Valve (TEV) be adjusted after installation?

Before leaving the factory, a specific superheat setting is made on each and every Parker Sporlan TEV. A standard superheat setting has been established for every size and every thermostatic charge. This standard setting provides the proper superheat on the average system to which the particular TEV size and charge is likely to be applied. Therefore, in most cases, a superheat adjustment on the job will not be necessary. Parker Sporlan recommends a change in the superheat adjustment only after it has been determined that it is required. Careful measurement of the operating superheat, using the recommended procedure, will establish if a change would be beneficial. To reduce the superheat, turn the adjusting stem COUNTERCLOCKWISE. To increase the superheat, turn the adjusting stem CLOCKWISE. When adjusting the valve, make no more than one turn of the stem at a time and observe the change in superheat closely to prevent over-shooting the desired setting. On adjustable TEVs, Parker Sporlan attempts to position the adjusting stem at the half-way point when it is at the standard setting. This allows maximum adjustment in both directions. Parker Sporlan supplies a number of OEMs with non-adjustable TEVs. The OEM determines the superheat setting through laboratory testing of the unit. Some of these valves can be converted in the field to adjustable models.

  How can I tell if my TEV is adjustable?

Most of the TEVs listed in Parker Sporlan Catalog 201 or Bulletin 10-10 will be adjustable unless there is an “N” stamped in the valve body as part of the nomenclature (i.e. NSVE-5). Many of the valves made specifically for OEM customers are non-adjustable. One way to tell if a valve is adjustable or non-adjustable is to look at the bottom cap. Adjustable expansion valves will have a threaded joint between the valve body and bottom cap as well as a threaded joint between the bottom cap and a hex seal cap that is removable to expose the adjusting stem. Non-adjustable valves on the other hand will generally have only one threaded joint between the valve body and bottom cap. An exception to this rule is a factory adjustable valve with two threaded joints and a smooth, round non-removable seal cap. Many non-adjustable valves can be converted to adjustable by changing the bottom cap assembly. Contact Parker Sporlan’s Technical Support department for more information. They will need all the information you can get from the valve’s markings to assist you. CAUTION: Never attempt to determine if a valve is adjustable by removing the bottom cap assembly unless the system has been pumped down, it could result in serious injury.

  Can I replace the power head on my Parker Sporlan TEV and how do I know what to get?

With a few exceptions, most Parker Sporlan thermostatic expansion valves manufactured after 1993 have replaceable thermostatic elements. The exceptions are valves with a “H” before the valve nomenclature (i.e. HSVE-10), the now obsolete Platform valves, and the relatively new HX valve. The Platform and HX valves can be identified by a stainless steel element. The valves with the “H” in the nomenclature have had the elements soldered to the valve body at the customer’s request. Parker Sporlan makes replacement element kits that are available through Authorized Sporlan Wholesalers. The thermostatic elements on Parker Sporlan expansion valves are identified by a series of numbers and letters. The number (i.e. 33, 43, 83, etc.) identifies the element size, while the letters (i.e. VGA, RC, JCP, etc.) identify the refrigerant and thermostatic charge. A replacement element kit can be obtained based on that information. For example, a valve with markings on the element of 83 and VCP100 will require a KT-83-VCP100 element kit. (For more information on element identification, consult Bulletin 210-60.) If markings on the element are no longer legible, contact Parker Sporlan’s Technical Support team for help in selecting a replacement element. They will need all information available from the valve body, and a description of the application. To completely identify a Parker Sporlan thermostatic element the following information is required:

• Element size number
• Refrigerant Thermostatic charge
• MOP (Maximum Operating Pressure) if other than standard E
• Capillary tubing length
• Bulb size if other than standard

For more information on Thermostatic Expansion Valves (TEVs) download a copy of Bulletin 10-10. For more troubleshooting information download a copy of 12 Solutions for Fixing Common TEV Problems - Form 10-143.

 

HVACR Tech Tip Article contributed by Jason Forshee, application engineer,  Sporlan Division of Parker Hannifin

 

 

 

 

 

Additional HVACR Tech Tips helpful for you: 

HVACR Tech Tip: Basic Troubleshooting Given Three Measurements

HVACR Tech Tip: Principles of Thermostatic Expansion Valves

HVACR Tech Tip: Where Should the TEV External Equalizer Be Installed?

Parker Sporlan's new web-based product selection program, Virtual Engineer, allows the user to size, select and fully configure products for Air Conditioning and Refrigeration applications. Virtual Engineer features quick selection of single or multiple components by template. An innovative dashboard and project system make saving, editing, and sharing projects easy. 

Virtual Engineer replaces Parker Sporlan’s legacy Selection Program. The legacy Selection Program was originally created to perform distributor calculations for internal purposes. Over the years, its use expanded to include many of the products Parker Sporlan offers and became an industry standard tool for selecting products in HVACR applications. 

By using Virtual Engineer, OEMs, Wholesalers, and Contractors can select the latest Parker Sporlan products with the most up-to-date refrigerants available on the market today. Users can select and size easily while out on the job site, in the equipment room or from their office. Parker Sporlan is committed to serving the HVACR industry with new and updated innovative tools to help users get the job done quickly and efficiently.

Virtual Engineer highlights 17 product areas with a basic template layout.

Product areas:

• Distributors

• Expansion Valves

• Solenoid Valves – Discharge, Suction, Liquid

• Catch-Alls® – Liquid, Suction          

• Suction Filters

• Discharge Bypass Valves

• Evaporator Pressure Regulators

• Discharge MTW Valves

• Head Pressure Control Valves

• Differential Pressure Regulators

• Temperature Responsive Valves

• 3-Way Hot Gas Defrost Valves

• Condenser Split Solenoid Valves

• 3-Way Heat Reclaim Valves

• Secondary Coolant Valves

• Liquid, Discharge and Suction Line Sizing

• Flash Gas Bypass and Gas Cooler Valves

 

Getting started - Background and the basics

With the use of an interactive template, all product areas are represented on the Dashboard when the user accesses the login page. The user can toggle from part to part from within the different categories, then is prompted to enter specific information when the part is chosen. Once a part is chosen, the Sizing and Configuration tools for each product appears. This feature is particularly valuable in systems such as cooling loops in which the optimal sizing and selection path is not intuitive. First-time users can now complete sizing and selection with minimal assistance.

Virtual Engineer allows refrigerant and product updates to become available as they are released. The web-based aspect of it ensures users are working with the latest version of the program. The HTML5 interface makes it scalable to the screen size being used. NIST Refrprop 10.0 is used for the refrigerant properties.

Popular system features from the previous Selection Program such as line sizing and thermodynamic reports have been carried over to Virtual Engineer. Thermodynamic reports have been expanded to include Pressure-Enthalpy, Pressure-Temperature and Enthalpy-Temperature graphs.

“We are excited about several new tools in the Virtual Engineer package, including the ability to size electric valves and mechanical valves in the same tool allowing for side-by-side loading analysis. The new software also allows for sizing of a wider range of electric valves including the Modulating 3-Way Valves, electric head pressure control valves, and Transcritical CO2 products. The new tools build on Parker Sporlan’s legacy of supporting the HVACR industry and providing new, innovative tools that help users get the job done.” 

Dustin Searcy, division marketing manager, Sporlan Division

 

Your step-by-step guide to using Virtual Engineer

Save design engineering time with these simple steps:

Step 1: Click to access Parker Sporlan's Virtual Engineer. 

Step 2: Choose your product category using the interactive interface.

Step 3: Size, select and compare products that meet the requirements of your application.

Step 4: Find a wholesaler, create your personal account, share your project, and/or download files.

 

Step 1: Access Parker Sporlan's Virtual Engineer 

This is what you'll see.

 

  Step 2: Choose your product category using the interactive interface.
 

• Use the grey arrows to toggle forward and backward to find your product category. 

• Once you've identified your product category, click the image to load the sizing tool.

 

 

Step 3: Size, select and compare products that meet the requirements of your application.
 

In this example, the Expansion Valve sizing tool is chosen, located in the Expansion Devices section.

• The Product Info icon takes you to the Expansion Valve's product page. Each product page is specific to that product family. This page will include a product overview, specifications, literature and other product support materials.

• Enter your system information in the required red field boxes. Virtual Engineer will alert you if an incorrect value is entered. As information is entered, the available products will be filtered on the right side of the screen.

• You can also Save Progress and Reset Parameters using the tools in the upper right column.  Saving your progress will require you to create a free account with Virtual Engineer.

• After entering your parameters, click the Compare button at the top right of the screen. All available options are included in the compare table by default.  You can deselect these as necessary. The Compare button will bring up the Compare Table.

 

 

• In the below example we will compare a thermostatic expansion valve with an electric expansion valve. After making your selections, you can create PDF report (RPT field) containing all your inputs, valve selection, and calculated values or export the values in an Excel file.
• Clicking the Configure button will open an eConfigurator that will allow you to further define your valve and create a part number, relevant values will be preselected.

 

 

• The Save button on the eConfigurator will take you to a login page and the My Projects section of Virtual Engineer.

 

Step 4:  Find a wholesaler, create your personal account, share your project, and/or download files.

• Login or create an account to access My Projects. Creating an account in Virtual Engineer is free.

 

 

• Add your part to an existing project, or create a new one. Next create a system inside your project. There is no limit to the number of projects or systems you have.

 

• The next screen that follows is the System Dashboard. 

 

• Inside the dashboard, clicking View Detailed System Summary will create a PDF of all system conditions, valve selections, part numbers, and calculated values.
• The Where To Buy button will allow you to locate your closest Sporlan Authorized Wholesaler.
• Share Your System will allow you to share the details of your system with a Sporlan Application Engineer.
• The Thermo Tool allows you to generate Pressure Temperature charts for most refrigerants. It will also allow you to create Pressure-Enthalpy, Pressure-Temperature and Enthalpy-Temperature graphs.
   

Article contributed by Jason Forshee, application engineer, Sporlan Division of Parker Hannifin

 

 

 

 

Related, helpful content for you:

HVACR Tech Tip: Guidelines for How to Size Solenoid Valves for Split Condensers

HVACR Tech Tip: Basic Troubleshooting Given Three Measurements

HVACR Tech Tip: Understanding Heat Pump Systems and Thermostatic Expansion Valves

HVACR Tech Tip: Interchangeable Cartridge Style Thermostatic Expansion Valves Save Time & Money

 

 

Non-condensable gasses such as air, hydrogen, nitrogen and hydrocarbons reduce the overall efficiency of refrigeration systems. The effects of non-condensable gasses, in a refrigeration system, increase the system operating pressures. These in turn negatively affect system performance. Increased compressor discharge temperature, higher energy costs, reduced system efficiency, leaks due to higher pressures, and increased wear on mechanical components are all negative consequences of non-condensable gasses in refrigeration systems.

The build-up of non-condensable gasses in the system can be attributed to several factors. These include inadequate system evacuation during service of system equipment, additions of refrigerant, leaks through external seals on equipment as well as refrigerant and oil decomposition.

Common indicators of non-condensable gasses in the system are excessively high condensing pressure or temperature and deviations in the pressure and temperature relationship at saturation conditions. This can be determined by checking the temperature and pressure relationship at a known point in the system where the refrigerant is saturated, such as the condenser drain legs or high pressure receiver, as illustrated in Figure 1. A higher temperature measured at this point, compared to the saturation pressure, indicates the presence of non-condensable gasses in the system.

 

Reduced efficiency

Ammonia refrigeration systems can be robbed of efficiency due to the presences of non-condensables in the system. These gasses lower heat transfer in coils as they take up space that should be occupied by the refrigerant itself. This can result in an overall efficiency reduction. These gasses can also cause compressors to work harder than they should due to increased head pressures in the system. Overall the presence of non-condensables causes your ammonia refrigeration to work harder than it should. 

For example, a 20 psi head pressure increase will result in more than 5% decreased system capacity. 

 

Increased operating costs

The decreased efficiency caused by non-condensables will result in higher power requirements for your system and this additional power comes at a great expense. 

Using the same example, a 20 psi head pressure increase will result in a 10% increase in energy consumption. For every 100 tons of capacity a system operating 6500 hours per year would result in $6300 of additional operating costs. 

 

A safe and effective solution

The V300 Rapid Purger from Parker Sporlan’s Refrigeration Business Unit will safely and effectively remove these non-condensables from your system and restore your system to its peak operational efficiency. The V300 is the 3rd generation of purger technology from Parker and is based on years of experience and testing. The V300 uses both pressure and temperature monitoring combined with a proprietary algorithm to automatically remove the air from the system in a safe and effective manner. If you are working on a system that is showing signs of increased head pressure or decreased operational efficiency the V300 can restore your system to its best.

The V300 Rapid Purger also has the ability to monitor the ammonia loss history. This function calculates the amount of ammonia lost during a standard purge cycle using a proprietary algorithm developed by Parker. Our engineers worked with live ammonia systems, including our own Broadview Ammonia Test Facility, to develop this algorithm based on real world applications and conditions. The result is that the V300 Rapid Purger can now display the amount of ammonia lost as part of its standard history display. The ammonia loss history can be viewed by week, by day, and by point:

Ammonia loss by week

 

Ammonia loss by day

The ammonia loss history will make compliance and reporting even easier when using a Parker Sporlan Rapid Purger. For additional information on the V300 Rapid Purger please click here or call us at 800-506-4261.

 

Download the Parker Sporlan V300 Purger product bulletin here.

 

Article contributed by Drew Stock, business development manager, Sporlan Division of Parker Hannifin.

 

 

 

 

Additional resources for you:

Compressor Overheating is the Number One Refrigeration Problem

Six Reasons Why CDS Conversion Reduces Costs

Using P-T Analysis as a Service Tool for Refrigeration Systems

Contractors provide service to customers with many different system applications in the field with an even wider variety of capacity requirements. Today, the number of refrigerants that a contractor might encounter is simply never ending! While not every system is fitted with a TEV, there are literally thousands of different TEV variations in the market place.

Can you imagine how hard-pressed wholesalers are to stock every version of a valve that might be needed for routine service? This is mind-boggling and needless to say, the contractor is even more unlikely to have the right valve on a service truck for that emergency service or repair job.

 

How does a contractor or wholesaler solve this problem?

Turn to Sporlan’s interchangeable cartridge style TEV product line, the type Q and BQ. Simply select the thermostatic element, the body and the right sized cartridge for the application and assemble the parts. They are even available with conventional (Q) and balanced port (BQ) construction. These easy to select and assemble valves mean you’re always carrying the right valve for the job.

Carry the Sporlan Q and BQ valve on your truck and stay on the job…not cruising around looking for parts! You save time and keep customers happy. It is simple. It is easy. It is economical. It just makes sense.

 

What are the advantages of the Q and BQ thermostatic expansion valves?

The mix-and-match components of the Q and BQ product line satisfy thousands of applications. With access to these components, you will be able to assemble valves that are just right for most refrigerated cases, coolers, or freezers and even air conditioning applications.

 

What is involved in the valve assembly?

It is really very easy. Select the correct thermostatic element, the right body assembly and finally pick the cartridge required to handle the system load and thread them all together. Sporlan has easy to follow graphical instructions and literature.

 

 

 

What is so special about the way the cartridge is installed in these valves?

The Q and the BQ valve cartridge is installed through the top of the valve body. This unique design means these valves can use ODF solder or SAE flare fittings. It also means the valve capacity can be changed with a replacement cartridge and the connections can be left undisturbed; simply isolate the valve from system pressure and have at it. No need to remove the Q or BQ valve from the system. 

 

How do I make sure I have the right sized valve?

With 7 different cartridge sizes for the type Q valve and 5 different sized cartridges for the balanced port type BQ, including a bleed port option in 4 of the BQ cartridges, you have many options available to put the right valve together for the job. 

 

What types of refrigerants are compatible with the Q and BQ valves?

The Q and BQ valves are compatible with the new refrigerants on the market, like R-448A and R-449A. They are also compatible with R-22 and the common replacements such as R-422D, R-407A, R-407C and R-407F. And the BQ with its balanced port construction is perfect for high-pressure refrigerants like R-410A. 

The replaceable thermostatic element feature increases the flexibility of the Q and BQ thermostatic expansion valves. This allows the thermostatic elements to be replaced during system conversions to a new refrigerant, or for service, without replacing the valve or removing the valve from the system.

 

Why should I carry a Q and BQ TEV case?

Carrying a stocked Q or BQ TEV case helps prepare contractors and service technicians for most situations - eliminating costly trips back and forth to the wholesaler and special orders. The case can be customized with the components in the greatest demand. With just the components supplied in the Q or BQ case, you can configure valves to satisfy over 100 unique applications.

Learn more about Parker Sporlan Q and BQ thermostatic expansion valves:

Bulletin 10-10 - Sporlan Thermostatic Expansion Valves

Bulletin 210-10-19 - Sporlan BQ Cross Reference

Form 10-165 - Sporlan Type Q and BQ - Interchangable Cartridge TEVs

SD-240 - Parker Sporlan Q and BQ Thermostatic Expansion Valve installation instructions

 

For more information on Parker Sporlan products please visit our website.

 

Article contributed by Jim Jansen, senior application engineer, Sporlan Division of Parker Hannifin

 

 

 

 

 

Additional resources on HVACR Tech Tips:

HVACR Tech Tip: Understanding and Preventing Superheat Hunting in TEVs

HVACR Tech Tip: Using Bi-Directional Solenoid Valves for Heat Pumps

HVACR Tech Tip: Troubleshooting Solenoid Valves in Refrigeration Applications

A refrigerant distributor is a device connected to the outlet of an expansion valve when paired with a multi-circuit evaporator. The outlet of the distributor is machined to accept tubing which connects the distributor to each evaporator coil circuit.

A portion of the liquid refrigerant passing through the expansion valve normally flashes, resulting in two-phase (liquid and vapor) flow at the valve outlet. This mixture is predominately liquid by weight, but the vapor occupies most of the volume. An additional problem arises due to the fact that liquid and vapor move at different velocities. This is sometimes referred to as slip, since gravity has a greater influence on the liquid portion of the flow than the vapor portion.

If a simple header is used instead of a refrigerant distributor, circuits will not receive equal amounts of refrigerant. This is because there is a natural tendency for the liquid and vapor to separate, resulting in unequal amounts of liquid being fed to the various circuits. Gravity will pull the liquid to the lower circuits, and vapor will go to the upper circuits. This will lead to hunting from the expansion valve and possibly cause flood-back issues.

To achieve proper distribution, the liquid portion of the two-phase flow must be divided equally to each evaporator coil circuit. Two-phase refrigerant flow leaving the expansion valve enters the distributor nozzle. The nozzle increases the velocity of the two-phase flow, mixing its liquid and vapor components. Furthermore, the nozzle is positioned such that flow is focused onto the dispersion cone, equally dividing the mixture into passageways spaced evenly around the cone. The refrigerant is then transferred to each evaporator circuit through the distributor tubes.

To ensure equal refrigerant flow, it is important to size the distributor nozzle and tubes to match the system capacity as closely as possible. By doing this, the proper pressure drops and velocities are created to completely mix the liquid and vapor.

In addition to feeding equal amounts of liquid and vapor into each circuit to utilize the full capacity of the evaporator, each circuit must be equally loaded. Figure A is a schematic illustration of typical temperature conditions in the evaporator when both equal distribution and equal loading occur.

Figure B illustrates the same evaporator but with the air flow (and thus the load) less over circuit #3. The load imbalance will be indicated by low superheat at the outlet of circuit #3, and high super-heat at the outlet of circuits #1 and #2. Other symptoms are lower than normal suction pressure, reduced evaporator capacity and expansion valve hunting with possible flood-back.

Optimum distributor performance is obtained when the distributor is mounted directly to the expansion valve outlet. If the distributor cannot be mounted directly to the valve outlet, it can be connected by a piece of straight tubing. The tubing should not exceed two feet, and it should be sized to maintain high refrigerant velocities. Elbows located between the expansion valve and distributor hinder proper distribution, and are not recommended. The expansion valve should be tied to a single distributor. Multiple distributors on a single expansion valve results in poor refrigerant distribution in the evaporator coil.

A distributor can be mounted in any position. If the system operates over widely varying conditions, best performance is usually obtained when the distributor feeds vertically upward or downward, see Figure C. For applications where the distributor is not mounted directly to the expansion valve, the vertical feed arrangement is recommended.

When planning a system refrigerant conversion, it is critical to consider nozzle and tube sizing due to differing net refrigerating effects of refrigerants. For complete sizing and application information refer to Parker Sporlan Bulletin 20-10.

A product selection program is available at www.Parker.com/Sporlan. View Parker Sporlan Refrigerant Distributors here.

 

HVACR Tech Tip Article contributed by Jason Forshee, application engineer,  Sporlan Division of Parker Hannifin

 

 

 

 

 

Additional resources for you:

HVACR Tech Tip: What You Need to Know About Flooded Head Pressure Control

HVACR Tech Tip: Guidelines for How to Size Solenoid Valves for Split Condensers

HVACR Tech Tip: Guide to Servicing Blended Refrigerants

HVACR Tech Tip: 12 Solutions for Fixing Common TEV Problems