wholesale tev


THERMOSTATIC EXPANSION

VALVES (TEV’S)

Wholesaler Training Program – Part 1


Thermostatic Expansion Valves

General

Thermostatic expansion valves and solenoid valves

were Sporlan’s first products. Sporlan calls the

device a “thermostatic expansion valve” abbreviated

“TEV”. Among industry person- nel it may also be

referred to as a “Thermo Valve”, “TX Valve” or just

“expansion valve”.

The TEV product line has grown to include many

different body styles for use on many refrigerants for

many applications.


Thermostatic Expansion Valves

Its principle of operation is explained in Bulletins 10-9

and 10-10 but in the simplest of terms, it is merely a

refrigerant metering device to regulate the proper

amount of refrigerant flow into the evaporator. It

accomplishes this by sensing and regulating the

amount of superheat at the outlet of the evaporator

where the bulb is fastened to the suction line.

Superheat is a term that will be heard frequently

when discussing TEV’s. In order to become more

knowledgeable on their operation a more thorough

study of “superheat” is suggested.


The Valve Types

Basic valve types have always been identified by

letters. Unfortunately there is a limit to the number of

letters in the alphabet so as Sporlan has expanded

its line over the years it has been necessary to use

some letters a second time usually after the original

valve model has discontinued for a period of time.

For the sake of simplicity each standard cataloged

valve has certain standard specifications supplied

unless otherwise specified. Some deviations are

possible on special order but are limited and should

be avoided to eliminate delays and special handling.

The following describe the standard specifications.


Type of Connections

Flare (also called SAE):

To connect a copper line to a valve having an SAE

connection, it is only necessary to “flare” the end of

the line and connect to the valve with the correspon-

ding size of flare nut. SAE connections are usually

1/4, 3/8 or 1/2. 5/8 is rare and larger sizes are not

available.

Valve types F, G and C have flare connections as a

standard in the sizes shown in Bulletin 10-10.


Type of Connections

Solder (also called “sweat” or ODF):

The nominal size for refrigeration tubing is measured

on the outside diameter (OD). Thus a 7/8 line size is

7/8” OD. To connect this line to the inlet of an

expansion valve, a 7/8 ODF (outside diameter -

female) inlet connection will allow the tube to slide

inside the fitting where the brazing or soldering takes

place.

Because of the never-ending combination of fitting

sizes the wholesaler normally stocks only the

standard connections. If the line size does not match

the standard connection, the use of reducing bushing

and/or couplings will allow the connection to be

made.

Standard valve types EG, S, SBF, EBS, O, SQ and

EQ are furnished with ODF connections.


Type of Connections

ODF flange connections:

A TEV with ODF flange connections has bolt-on steel

flanges with a brass bushing. The line is soldered to

the ODF bushing. The flange fits over the bushing

and is bolted to the valve body.

Once the bushings are brazed to the line installation

and removal of this type valve only requires bolting or

unbolting of the flange.

Types H, M, V and W are furnished with ODF flange

connections.


Type of Connections

FPT (Female pipe thread) connections:

Type D and A valves for ammonia have FPT flange

connections. Types H, M and V valves that normally

come with ODF flange connections can be adapted

to FPT with the H valve requiring special adaptors.


Other Standard Specifications

Nominal capacity:

The nominal capacities available for every valve type

is shown in Bulletin 10-10 for each refrigerant.

Capillary tube length:

The standard length for each valve type listed can

vary from 30 inches for the type F to 10 feet for the

W, D and A valves.

Size of power element:

Each valve type is made with a particular size of

power element (example: 53, 83, 33, et cetera).

The bulb size is determined by the thermostatic

charge furnished. Information on both element and

bulb size is also shown for each valve type in Bulletin

10-10.


Other Standard Specifications

Size and type of external equalizer connection:

All standard cataloged valves with SAE (Flare) and

flange connections have 1/4 SAE equalizer fittings as

standard. Those with ODF (Solder) connections are

furnished with 1/4 ODF external equalizer fittings.

The flanged H, M, V and W valves have 1/4 SAE

equalizer fittings. The D and A valves have 1/8 FPT

equalizer fittings.


More About Refrigerants and

Thermostatic Charges

Refrigerants

The material used in most valve types are compatible

with all common refrigerants. The principle exception

is the D and A valves which are used on ammonia

only.

The code letter for the refrigerant is always found in

the valve’s designation (GV is a type G valve for “22”

and GJ is for 134A). A complete list of refrigerants

and their letter code is in Bulletin 10-10.



Thermostatic ChargesThermostatic Charges

Like body types and refrigerants, thermostatic charges are also identified by a letter. Generally, each charge covers an evaporator temperature range but some other application considerations can be involved particularly on the pressure-limit or maximum operating pressure (MOP) charges designated by the addition of the letter “P” and sometimes a number (example CP100).

Many of the thermostatic charges used with the newer refrigerants are interchangeable with the older refrigerants being replaced. As an example, the following refrigerants use the same thermostatic charge: R-12, R-134a, R-401A, and R-409A. This is further illustrated here for thermostatic charges use for commercial temperature ranges of -10°F to 50°F.

The pressure limit charges (MOP) will limit the amount a TEV opens so that the evaporator pressure will not exceed the “Nominal System” values shown. This can be an important feature at pull-down or after a defrost.



Thermostatic ChargesInternal or external equalizer

The purpose of the external equalizer (designated by the letter “E”) is to compensate for pressure drop through the evaporator and/or refrigerant distributor. It is generally known if a refrigerant distributor will be used on the evaporator. However, it is rare that wholesaler customers will know evaporator pressure drop. Therefore, the following rule-of-thumb is suggested:

A. Use the externally equalized valve on any evaporator equipped with a refrigerant distributor.

B. Use the externally equalized valve when there is any doubt and particularly on valves with nominal capacities above 1 ton. There is no disadvantage to using it even if it is not required.

C. Use the internally equalized valve on small tonnage TEV’s (below 1 ton) when it is known that the evaporator is single-circuit with no refrigerant distributor.


Balanced Port Thermostatic

Expansion Valves

The port construction of standard thermostatic

expansion valves is such that the pressure drop

across it (difference between inlet and outlet) tends

to open the valve. This pressure imbalance has little

effect on the TEV’s operation under most normal

operating conditions, particularly on small valves.



Expansion Valves

On larger valves with greater port areas it becomes

more of a factor and our type V and W valves have

always been made with semi balanced ports. The

type “O” valve was later introduced which has a

completely balanced port.



Expansion Valves

The type “O” valve with its balanced port construction

has been widely accepted for its ability to maintain

close control under conditions of varying inlet

pressure and fluctuating loads. With its large capacity

ratings the O valve is ideally suited for chillers or

other applications where head pressure can fall and

loads can change.



Expansion Valves

The balanced port version of the F valve is the Type

BF, EBF and SBF. The balanced port S valve is type

EBS.

Bulletin 10-10 provides further information on the BF

valve.


Power Elements

The power elements are replaceable on most standard TEV’s.

The power element consists of the bulb, capil- larytube, diaphragm case assembly and the thermostatic charge it contains. Replacement power elements are supplied in kit form with a prefix KT (for Kit, Thermostatic) to the designation followed by a number indicating the lock ring size, as well as the refrigerant letter designation. The length of the cap tube should also be specified when ordering. This KT-83-VCP100 indicates the following:

1. KT - 83 Element size 83

2. V Refrigerant 22

3. CP100 Thermostatic charge CP100


About Changing Power Elements

The type “Q” Valve is designed to provide the

flexibility for changing power elements and nominal

capacities. For more information about the Type Q

Valve, there is a separate program available covering

its features. When other standard valves are involved

in power element changes, other considerations are

involved:


About Changing Power Elements

When changing from one thermostatic charge to another using the same refrigerant, the nominal capacity remains the same and the stamping on the valve body will still reflect the correction identification. However, the customer should be advised that a super-heat adjustment might be required.

When changing from one refrigerant to another, the nominal capacity will probably change. As an example, the same port size is rated for nominal 5 tons on R-22 and 3 tons on R-12 and R-134a. Also, it is very likely that a superheat adjustment will be required because of variations in the superheat spring sizes. One other point to remember is that the identification stamped on the valve body, showing the original refrigerant and nominal capacity, will no longer correctly identify the valve. The Q valve design is such that these problems are eliminated.


Supplying the Customer with the

Correct TEV

Wholesalers are often confronted with the problem of

supplying their customers with the correct TEV based

on information that is incomplete, or inaccurate.

When this occurs, asking the right questions can

often lead to a solution. Generally, one of the

following situations is involved:



Correct TEVSelection of a TEV for a new application

This can become a case of how precise the customer may be in his requirements. One extreme is the engineer who supplies every detail on the system characteristics. On the other end of the scale is the service mechanic who may say, “give me a 5 ton valve!”

Finding the correct valve capacity

The nominal capacity rating (except for ammonia) is based on:

a. 40 degrees F evaporator temperature

b. 100 PSI pressure drop across TEV (60 PSI for R-134a)

c. 100 degrees F vapor-free liquid entering TEV.

TEV’s for air conditioning applications including water chillers will usually fall roughly into the conditions shown above. This means that a nominal 5 ton valve will be selected for a 5 ton or 5 horsepower system. This situation calls for an SVE-5- CP100 or SVE-5-GA.



Correct TEVFor refrigeration applications the selection can become a little more involved, particularly when operating conditions become more variable.

TEV capacity tables assume that the pressure drop across it will be in accordance with the evaporator pressure that is expected at the particular evaporator temperature. In other words, with a constant discharge pressure (TEV inlet) the pressure drop increases as the evaporator pressure (temperature) is reduced. Therefore, for R-22 and equivalent refrigerants, the pressure drop is assumed to be 100 psi at a 40°F evaporator, 125 psi at 0°F to 10°F evaporator, 150 psi at -10°F to -20°F, and 175 psi drop at -40°F. The entering liquid temperature is based on 100°F at all evaporator temperatures.



Correct TEV

In the example shown, valve types NI, F, EF, G, &

EG all have rated capacities of 1.09 tons at a 20°F

evaporator and standard conditions of 125 psi

pressure drop and 100°F entering liquid

temperature.



Correct TEV

When the entering liquid temperature and/or

pressure drop across the TEV is significantly

different from stated standard

conditions, correction factors are applied to the

TEV’s rated capacity as shown in the capacity

tables.

In this example, an adjusted capacity is

calculated for the valve selected from the

capacity table based on standard conditions at a

20°F evaporator.



Correct TEV

The correction factor for 70°F liquid is found from

the table to be 1.17 and the factor for 100 psi is

shown as 0.89. The two correction factors

multiplied by each other and then times the rated

capacity of 1.09 results in new capacity of 1.13

tons and the type EGVE-1 is chosen for a one ton

load.



Correct TEVAssuming that a refrigerant distributor is used, a TEV with an external equalizer will be required. When determining the pressure drop through the evaporator, the drop across the distributor must be included. In this typical example, the suction pressure at the compressor is 43 psig, but the pressure at the outlet of the TEV is only 78 psig.

Therefore, an external equalizer is required designated by the letter “E”. Again, the purpose of the external equalizer is to compensate for the pressure drop through the evaporator and /or refrigerant distributor.

The final consideration is the thermostatic charge. Since the specified evaporator temperature is 20°F, a “C” charge is selected.

The complete designation for the selection is EGVE-1-C, 3/8 X 1/2 ODF-5”



Correct TEVSelecting a Replacement TEV For Another Sporlan Valve

• Standard Cataloged Valves

A. This is a case of getting the required information from the old valve not always an easy task!

B. Bulletin 210-60 will serve as a guide to directing the customer to the location of the identifying numbers and letters on the valve.

All Sporlan TEV’s have permanent identifying marks and most have an identifying label on the power element showing sufficient information to select a replacement. Unfortunately this label can become obliterated with age and it then becomes necessary to seek out the permanent markings as shown in Bulletin 210-60.



Correct TEV

Replacement of Special Non-Cataloged Valves

Sporlan manufactures many special TEV’s for OEM’s

- usually modifications of standard valves to meet the

particular requirements of their unit.

Identifying and selecting a replacement can often be

handled with the assistance of bulletins in the “210”

section of your wholesaler’s manual.



Correct TEVThe special designations will usually be one of the following:

• Type I or BI valve (example - IVE-2-GA, BIVE-2-GA and BBIVE-2-GA): Sporlan type Q or RCVE valves can often be matched to the specifications of these models. The BBI valve having a balanced port might be replaced by a type SBF. The above original valves will most likely be non-adjustable. The standard replacements will have adjustable superheat to allow for an adjustment to match any special setting that was originally furnished to the OEM.

• Type X Valve (example - XVE-7 1/2-CP100): This valve is usually field replaced with a standard type S, G, C, RCVE, or Q valve.

• Valves Identified with a “Y” Number (example - Y362GR-1-Z): These are the most difficult to identify since the “Y” numbers that Sporlan have used over the years is now in excess of 1,000 and each number signifies some special feature known only to Sporlan and perhaps the OEM. This then becomes a case of contacting Sporlan or directing the customer to the OEM involved. Delivery is usually long.



Correct TEVSelecting A Replacement For A Competitive TEV

This is another case where there can be no easy guide to making a proper selection because of the wide number of manufacturers and model numbers involved. Sporlan does publish a cross-reference table with competitive valves.

The cross references are based on nominal capacity matches. Valve performance, and thus system performance, cannot be guaranteed when replacing a valve using these cross references because of unique valve flow characteristics and potentially differing test and rating procedures by the valve manufacturers. There is also no assurance that the valve being replaced has been properly sized for the systemrequirements. Therefore it is always recommended to properly confirm the valve selection as outlined in Bulletin 10-10.

Note: This is a nominal capacity cross reference only. Physical attributes, such as connection sizes, body configuration, lay in dimensions, and capillary tube length may not be identical. Due to some of the differing valve physical attributes, some system modifications may be required.

Most wholesalers have competitive catalogs for reference.



Correct TEVIdentification of Numbers and/or Letters Not Commonly Encountered

Customers may occasionally provide unrecognizable designations other than “Y” numbers or OEM specials such as I, BI and X valves. The following are some of these cases:

• Suffix numbers to “P” charges (example GRE-2-ZP35): These numbers indicate a pressure limit other than standard. Bulletin 10-10 shows the standard pressure limit values for all standard charges. As an example the RZP standard factory air test settings is 45 PSI.

Therefore, an RZP35 charge has a pressure limit setting to 10 PSI below the standard RZP.



Correct TEV• BP and RPB: TEV’s with either of these features

are designed for use on systems having a “low starting torque” compressor motor (such as permanent split capacitor or PC motor). This type of compressor will start only if there is a negligible difference in high and low side pressures.

Both the BP and the RPB features allow the TEV to equalize the high and low side pressures when the compressor is stopped. When restarting there is virtually no pressure difference and the compressor is stopped.

• The letters BP stand for “bleed port” and will be followed by a number to indicate the percent of bleed. Thus BP/30 means a 30% bleed.



Correct TEV

The letters RPB stand for “rapid pressure balance”

and does not include a number as in the case of

straight bleed-port valves (BP).

Replacement of a TEV on a system with a PSC

motor (low starting torque) must have a bleed port or

RPB feature. A standard TEV without the BP or RPB

can only be used by adding a “hard-start kit” to the

compressor motor. Also 3-phase compressor motors

do not require the BP or RPB feature.

Non-adjustable TEV’s: Some standard models of

TEV’s are made non-adjustable for OEM’s. The

designation for these use the “N” prefix such as

NSVE-8 which is replaced in the field by a standard

SVE-8.



Correct TEVReplacement Parts for TEV’s

Sporlan TEV’s are very trouble-free and service or necessity for replacement parts is extremely rare. Most complaints involving the operation of TEV’s can usually be traced to contaminants in the refrigerant. It is a well established fact that because of the valve’s location in the system, even the smallest trace of circulating contaminants will eventually be trapped by the TEV. Of course the Sporlan Catch-All is the best insurance against this happening and will be discussed later.

Wear to any of the TEV parts is practically nonexistent which leaves only the loss of the thermostatic charge as a possible source of TEV failure. Replacement power element kits are available for this purpose.

In general, even though replacement internal parts kits are available for some valves, repairing of TEV’s is considered impractical because of the cost of labor compared to the cost of a new valve.


REFRIGERANT

DISTRIBUTORS



Refrigerant Distributors

General

The refrigerant distributor is a device not often sold

by a wholesaler since it is usually included with the

evaporator coil by the OEM. Nevertheless, the

wholesaler is frequently called on to supply parts to

modify it to accommodate some design change such

as a change in refrigerants, capacity or addition of

hot gas defrost or hot gas bypass.



Basic Distributor Construction

Standard refrigerant distributors consist of 3 parts:

A. Body (designated by 4 digit number, i.e.: 1113)

B. Nozzle (designated by a letter and a number, i.e.:

G-6)

C. Retainer Ring (designated by same letter as

nozzle)




Bulletin 20-10 is the guide to finding:

A. Number and size of circuits available for each

distributor body.

B. Nozzle type (L, J, G, E, C, or A) that fit a particular

distributor model.

C. Nozzle orifice size and corresponding capacity for

each (numbered 1/9 to 50).




Refrigerant distributors for hot gas defrost, heat pump, or reverse flow (distributors with auxiliary side connectors)

A. The 1650 series (1650, 1, 2, 3, 4, 5, 6, 7, 9) are constructed with a connection on the side to receive hot gas for defrost purposes or to collect liquid from the evaporator on reverse flow such as a heat pump.

B. Models 1651, 3, 5, 7 and 9 use standard nozzles J, G, E, C, and A respectively. Models 1650, 2, 4 and 6 have nozzles that cannot be removed.

C. The purpose for using all the above models instead of a “Tee” between the TEV and distributor is to allow the hot gas or reverse flow to pass through the distributor without going through the restriction of the nozzle.




Refrigerant distributors for hot gas bypass:

A. Refrigerant distributors for hot gas bypass

applications have the same basic construction

except for the internal machining of the

distributor body and the use of a “extended tube”

nozzle. Both are designated by the letter “R”

added to the number of the distributor and/or

nozzle. Example: 1653R for the distributor and

GR for the nozzle.




Refrigerant distributors for hot gas bypass:

B. The “R” models use special distributor body

machining and special nozzles to permit the

mixing of the hot gas from the bypass valve and

the refrigerant feed from the TEV. This is

accomplished without upsetting the proper

refrigerant distribution into each circuit of the

distributor.

C. “R” models can be used on both hot gas bypass

and hot gas defrost and reverse flow systems.

However, the standard 1650 series (without “R”)

should not be used on hot gas bypass systems.




Converting standard distributors to side outlet models:

Customers will occasionally want to add hot gas bypass or hot gas defrost to an evaporator that was originally furnished with a standard distributor.

This can be accomplished with the use of an auxiliary side connector (ASC).

A. ASC models that fit standard model distributors are listed in bulletin 20-10.

B. Customers should follow the instructions for locating the ASC and relocating the nozzle from the distributor to the ASC.




C. The ASC adapter provides a second option for

supplying a customer with a distributor with an

auxiliary side connection. In this example, a

1651R-3-1/4-4 with a 1/2 OD side connection

serves the same purpose as a 1620-3-1/4 in

combination with an ASC-5-4 using a J-4 nozzle.


LEVEL-MASTER CONTROL



Sporlan Level-Master Control

The Sporlan Level Master control is a modified TEV designed for application to flooded systems only. The basic difference between the Level-Master and a TEV is in the construction of the power element. This LMC element has an insert type bulb and contains a small heating element. The complete power element including the heater is available as a separate part. The heater only is also available as a replacement part.

The Level-Master has limited application because of the relatively small number of flooded refrigeration systems in existence or being built. Most flooded systems use ammonia and are usually found in industrial applications.

Bulletin 60-15 gives details of construction, operation and application.

wholesale tev

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