Kele & Associates is branchingout to bring you another sourceto rely on, experience you cantrust and products you can counton! Kele & Associates hasworked with Contractor Instruments in Minneapolis, Minnesotathrough a mutual business partner-ship. Over thelast few years,the two compa-nies have shared common owner-ship, yet we haveoperated as separate entities.

By the end of this year, these twocompanies will merge and operate as one. Contractor Instruments will become knownas the Kele & Associates Mid-Western branch office. Dale Pederson, President of Contractor Instruments, feels thestrength of Kele and the range ofKele products will provide moreoptions and services to cus-tomers in the upper Mid-Westernarea. We feel the experiencedand dedicated Contractor Instruments Associates will be atremendous asset to Kele.

Contractor Instruments, Inc. willcontinue to operate its manufac-turing division (IES) independent-ly, serving OEM and industrialcustomers. The efforts at thisoffice will continue to focus ontheir experience and capability in

the area of in-house engineering,design, testing, manufacturingand servicing of quality productsfor building HVAC energy au-tomation and control.

For the convenience of customersin the Minneapolis and surround-ing areas, a Local Sales Counterhas been added along with increasing the available inventory by adding many popu-lar temperature controls andKele products to the shelf. Joe Romain, a nine-year Contractor Instruments veteran,will provide local sales, customer service and technical support.Bobbi Hector and Jeff Ewert will assist with order entry, deliveryand returns. Layton Paine is theEnvironmental Controls ProductSales Manager with 29 years ofexperience in HVAC controls,systems, and applications. Theseprofessionals are teamed togeth-er to give you an expanded Kelesource for reliable service, prod-ucts and support.

Just for Grins 2

Protecting thePressure Transmitter 3

HazardousAtmospheres:Explosion Proof 4

Questions fromthe Field 6

InteractiveIdeas 7

Products:WD-1B-TPCM 8

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Volume 9, No. 1 Spring 199920/20

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(901) 937-4900 • www.kele.com(901) 382-6084 (International)

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(Left to Right) Jeff Ewert, Bobbi Hector, Joe Romain, and Layton Paine

On The Inside

Continued on page 3

Special Interest ,Just For

April XXVII, I BC

Citizen Rennius Augustus, ManagerAutomated Systems of Rome, Inc.MCCXIX Via de la RosaRome, Italy MMDCLXIII

Re: Y-zero-K

Good Citizen Rennius,

This is my IIIrd request to you for documentation certifying that our automation system will behave properly when the year turns to zero in eight months. I understand that you have been awaiting documenta-tion from your manufacturer, who is in turn awaiting documentation from component suppliers, who are inturn awaiting documentation from the makers of the embedded calendars. However, none of this “awaiting”is going to keep our systems running next January I. I wish you were as quick as Kele & Associates! Theyhave already advised me that all of their hourglass system interface products are not only Y-zero-K compliant,but also Y2K compliant as well (as if the world could last that long!).

Please advise me by return courier if the Julian Upgrade Package that we purchased for all of our stand-alonecalendar/sundial units is Y-zero-K compliant. If a Y-zero-K upgrade is required, I will need to know the costas soon as possible so I can decide how to proceed. If the cost is high, I may decide to integrate these stand-alone units into my enterprise hourglass system, so please provide separate module pricing for this option.

My consulting philosophers have been preparing a BC-to-AD transition plan for almost a year now, but as usual all they have delivered are some really big invoices. They seem to be intent on finding a way to continue the downward count into minus-BC but I don’t expect they’ll have much luck in making my sundials work the other way around. I can’t foresee any sand falling up through an hourglass, either.

I hear over in Greece that the Oracle at Delphi is predicting crisis, pestilence, and famine when the year turns, while the Oracle at Rhodes says it’ll be no big deal. Who can you trust?

Again, please help me out as quickly as you can. I have enough grief with my newest office tower beginning to tip over, I really don’t need this Y-zero-K headache.

Pax,

Marcus Janius

Editor’s Note: Since the Leaning Tower of Pisa was constructed in the 12th century A. D., we initially suspected that this docu-ment was a forgery. However, further research revealed that the tower we know today is actually Phase III of an office towercomplex that was begun in about 10 BC. The first two towers subsequently tipped all the way over, although these events werevery effectively “hushed up” since Tiberius Caesar had a substantial financial interest in the general contractor.

2

VVM Building ManagementPisa, Italy

“The Empire’s Largest Purveyor of Property”

A parchment recently unearthed in Southern Italy . . .

Measuring steam pressure is a common application in the HVAC industry,but finding a transmitter that can handle the higher temperatures of steamcan be a challenge. Steam, under typical HVAC and process pressures,may reach temperatures ranging from 212°F to 400°F, but most pressuretransmitters’ maximum temperature limits are around 200°F. An inexpensiveand effective solution is to install a steam syphon between the steamsource and the pressure transmitter. The Model PT steam syphon from Kele & Associates is an excellent choice.

The steam syphon protects the transmitters from the extreme temperatureof steam. The key to an effective steam syphon is the condensate thatforms in the syphon loop (see Figure 1). This water barrier not only acts asa heat buffer, but also protects the transmitter from harsh chemicals and im-purities as well. In new installations, it is recommended that water be addedto the syphon to protect the transmitter in the initial startup when conden-sate has not yet formed.

The Model PT steam syphon is good for systems up to 400°F. Higher temperatures will require additional mea-sures to dissipate the greater amounts of heat. These additional measures are effectively nothing more thanputting more distance between the steam and the transmitter. For more information on temperature rangeshigher than 400°F visit http://www.kele.com/Tech/Monitor/Pressure/TRefPres7.html. For best results mount theModel PT in an upright vertical position.

Additional transmitter protection may be needed from sudden pressure shock waves. In these instances the47S stainless steel snubber from Kele & Associates mounted between the transmitter and the Model PTdampens the effects of shock waves and prevents transmitter damage.

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Technical t

Kele & AssociatesP.O. Box 34817 • Memphis,TN 38184

ATTN: Steve Carney • Phone: 901-937-4940FAX: 901-372-2531 • E-mail: stevec@kele.com

Please Address All Comments To: 20/20

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20/20 Insights is an official publication of Kele & Associates

Water

Air

Steam (400°F)

Pipe

PressureTransmitter

Fig. 1

We are proud to have these professionals as a partof the Kele & Associates family. We welcome themand wish them the best of luck with the new respon-sibilities that come in branching out with the Kelename.

Local Phone 612-934-1810Local FAX 612-934-9118

Out of State1-800-758-HVAC (4822)

E-mail: ciecp@sihope.com

6488 Carlson DriveEden Prairie, MN 55346

Continued from front page

Mid-Western Branch

Technical

Explosion Proof

In the last edition of 20/20 Insights we discussed the elements that must be presentin order to produce an explosion. The three legs of the “fire triangle” (fuel, oxy-gen, and an ignition source) are required to support combustion. In addition, thevolume ratio of fuel to air must be within the fuel’s explosive limits, and the ignitionsource must release sufficient energy to ignite the mixture. Removing any of thesethree elements will eliminate the explosion hazard.

Perhaps the most common and familiar way to eliminate ignition sources from ahazardous location is through the use of explosion proof construction. An enclo-sure that is rated explosion proof (NEMA 7, 8, 9, or 10) for a particular hazardgroup (explained below) is strong enough to withstand the pressure of a worst-case explosion inside itself. Additionally, it is designed to vent the resulting hotgases in such a way that they are cooled below the ignition temperature of aworst-case explosive mixture outside the box.

To contain the pressures of an explosion, these enclosures are made from heavycast steel or cast aluminum. To cool escaping gases, flanged enclosures have extra-wide flanges that are ground to a smooth finish and tight tolerance – thusyielding a very thin, very long path to the outside as shown in the illustration. Enclosures with threaded covers (and threaded connections to either type of enclosure) produce the same effect by virtue of the long, narrow path through thethreads. As the hot gases from an internal explosion pass through these long,

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CABLE SEALREQUIRED

EXPLOSIONINSIDE BOX

HOT GASES COOLED BYLONG EXPANSION PATH

THROUGH THREADS

FIBROUS PACKING

SEALING COMPOUND

CONDUIT SEAL

GROUND FLANGEJOINT PROVIDESLONG, NARROWPATH TO COOL

ESCAPING GASES

JACKETEDCABLE

narrow channels, they give up heat to the met-al and their pressure is reduced. These two effects team up to lower the temperature of thegases to a safe level before they can come incontact with the atmosphere surrounding theenclosure.

With flanged enclosures, it is very important totorque the cover bolts evenly and as close aspossible to the recommended value. Also, theflange surfaces must not be scratched ormarred in any way. Improper torque or damaged surfaces can allow hot gases to escape and ignite an explosive mixture outsidethe enclosure. Threaded connections or coversmust engage at least five full threads to main-tain the integrity of the system.

One additional step is needed to control thespread of hot gases – conduits entering the enclosure must be sealed within the code-re-quired distance (usually 18'') of the box to prevent the buildup of pressure within the raceway systemor the leakage of combustion products into the room. If ajacketed cable passes through a conduit seal, the jacketshould be removed within the seal so that the sealing com-pound can completely surround each insulated conductor.An alternative is to seal the cable at the end of the jacket asshown in the illustration.

So where can these types of enclosures be used? As usualin our industry, there are no easy answers! Each explosionproof enclosure will be listed or labeled for use in a particu-lar environment as defined in the National Electrical Code(NEC) or IEC Standards. In turn, the hazardous area itselfmust be classified according to the same standards. Theenclosure must have a listing that meets or exceeds the classification of the area in which it is to be used. In theNEC, considerations are Class, Division, and Group asshown in the table. IEC standards use different code lettersfrom the NEC but generally follow the same logic.

For gases (the majority of our industry’s hazards), explosionproof enclosures are readily available for Class I, Division 1, Groups C and D. Enclosures rated for Group B(hydrogen) can also be found, but generally only in smallsizes since it is so easily ignitable and has high explosiveenergy. Almost nothing is offered for Group A (acetylene)environments because of its easy ignition and tremendousexplosive energy.

Using explosion proof enclosures removes the ignition legfrom the “fire triangle” in a potentially hazardous location.Although it is costly and requires care to maintain the system’s integrity, it is an effective method for working withelectricity in combustible atmospheres. In a future 20/20Insights we will discuss intrinsically safe systems, anotherway to remove potential sources of ignition from hazardouslocations.

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NEMA Classifications - Marked with Rated Class, Division, and Group

NEMA 7 Class I (Gases) Indoor Hazardous Locations, Air-BreakNEMA 8 Class I (Gases) Indoor/Outdoor Hazardous Locations, Oil-ImmersedNEMA 9 Class II (Dusts) Indoor Hazardous LocationsNEMA 10 Meets U.S. Bureau of Mines Safety Requirements

Summary of NEC Classes and Group Examples

A AcetyleneB Hydrogen, Ethylene Oxide, Propylene OxideC Ether, Hydrogen Sulfide, Hydrazine, NitroethaneD Methane, Acetone, Benzene, Gasoline, NaphthaE Metallic Dusts (all metals) F Carbonaceous Dusts

(coal, asphalt, etc..)G Nonconductive Dusts

(grain, drugs, pesticides, plastics, dyes, etc..)

Group Class I (Gases) Class II (Dusts)

Summary of NEC Divisions

Division 1 Hazard always or frequently present, or may be present during normal operation, or high probability of hazard existing at the same time as electrical malfunction

Division 2 Hazard normally not present, or highly unlikely to be present at the same timeas electrical malfunction, or area adjacent to Division 1.

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Q: What is the benefit of the “Smart” LED optionfor the CS1150A and SCS1150A current switches?

A: The “Smart” LED simplifies the trip point adjust-ment of these current switches. When the LED isOFF, there is no current being sensed. When the LEDis flashing slowly, current is present but is below thetrip point of the switch. When the LED is flashingrapidly, the current is above the trip point and hastripped the current switch. To adjust the trip point,first energize the load being monitored. Next, simplyturn the 4-turn adjustment counter-clockwise untilthe LED flashing turns from fast to slow. Now turnthe adjustment clockwise until the fast flashing re-sumes. The switch is now tripped. It is advisable toturn the adjustment slightly further clockwise to pro-vide a margin for normal current variations.

Q: I have several definite purpose contactors that aremaking a humming noise. Is that normal?

A: It is not unusual for definite purpose contactors,motor starter coils and even some relays that are pow-ered by AC voltage and are electrically held to make aminor electrical humming sound. The intensity of thehum will vary with the size and type of device and isoften amplified when the device is mounted in a metalenclosure. It is best to locate these devices in an arealike a mechanical room where noise is not an issue. Ifthey must be located in a noise sensitive area such asabove a ceiling, a piece of foam (polyethylene closedcell pipe insulation works well) located between thecontactor and its mounting surface will minimize humand vibrations.

Q: The wiring terminals on many thermostats andpackaged HVAC units are designated by letters likeR, G, Y and W. What do these letters mean?

A. Most thermostat and HVAC unit manufacturershave adopted a standard terminal designation schemeof letters to identify the control function of theirwiring terminals. Here are the most common terminaldesignations and their typical connections:

Terminal Typical ConnectionDesignation

R Power connection to transformer (internally connected for heating and cooling)

RC Power connection to cooling transformer

RH Power connection to heating transformer

G Fan controlW1 Stage 1 heatingW2 Stage 2 heatingW3 Stage 3 heatingY1 Stage 1 coolingY2 Stage 2 coolingY3 Stage 3 coolingB Heating damper motor;

changeover valveO Cooling damper motor;

changeover valveE Emergency heat control

Designations for additional functions like remote over-ride, auxiliary relays, clogged filter indication, etc...,are not as standardized from one manufacturer to thenext. Also, the common letter designations are oftenused to refer to wiring colors. The R is for red, G forgreen, Y for yellow, W for white and so on. . .

Field questions are an important fact-gathering tool.Here are some more commonly asked questions fromthe field. The answers are provided by Kele Sales En-gineers—people who can make a big difference inyour project and product performance.

Idea #78: Instead of putting the new 1999 Kele & AssociatesCD-ROM into your computer’s CD drive every timeyou want to use it, just copy the CD-ROM to yourhard drive. Here’s how to do it:

1. Insert the Kele CD-ROM in your CD drive.2. Use Windows Explorer to view the contents of

the CD. Select the “1998cd” folder and copy tothe desired hard drive. Note that 211 MB offree space is required on your hard drive tocopy the “1998cd” folder.

3. If you have not previously installed the KeleCD, do so now by double clicking on the “install.exe” program on the CD.

4. Open the CD catalog by selecting the “1999Kele CD-ROM Catalog” from the start menuunder programs.

5. Once the program is running, select the “Options” button from the Kele CD controlpanel. On the menu there is a “Change Path”button. Click and select the location of the“1998cd” folder that you previously copied.Click OK to save the changes, close the KeleCD program and restart. The Kele CD programwill now open using the CD files on the harddrive instead of the actual CD. If you want togo back to using the CD, you would need todesignate the CD drive letter under the “Op-tions” button on the Kele CD control panel.

6. Don’t forget to create a shortcut on your computer’s desktop to the 1999 Kele Interactive CD-ROM!

Special Interest ,

interactiveideas

Idea #137 Save time preparing job submittals by using thenew 1999 Kele & Associates Interactive CD-ROM.The CD contains data sheets (PDF documentsread by Adobe Acrobat, available on the Kele CD)of all the products found in the Kele catalog.Many detailed instruction manuals are also in-cluded. The “Batch Print” function found on theCD control panel makes selecting and organizingdata sheets to print for submittals a simple mat-ter of pointing and clicking with your mouse. Youcan print your entire interface product submittalpackage in the order you want it, all from a singlesource. You can even customize your submittalby printing a custom heading on each data sheet.The 1999 Kele & Associates Interactive CD-ROMis another great reason to make Kele & Associ-ates your single source for building automationinterface devices and controls.

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Products r

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Contact Kele & Associates for information or pricing on these products. 901-937-4900 • FAX: 901-372-2531

International: 901-382-6084 • FAX: 901-388-1697E-mail: info@kele.com

The WD-1B-T is a tape style water detector that can be usedwith any “contact closure” monitoring device. It includes all ofthe standard features of the WD-1B, plus a self adhesivesensing tape with copper electrodes and a cotton cover. Conductive liquids can be sensed anywhere along the lengthof the tape. The SPDT contacts make on moisture detectionand release when dry. A weatherproof enclosure, power LED(green) and alarm LED (red) are standard. The sensing tapeis 1.5'' wide, 0.1'' high and comes in lengths of 10, 20 and 50feet that can be cut in the field for your specific application.The WD-1B-T can be powered by 11 to 27 VAC/VDC.

The PCM pressure controlmodule is a combination setpoint controller and airpressure transmitter. ThePCM is available in 2'', 3'', or5'' W.C. ranges. Some of themore prominent features include Proportional or Proportional/Integral control,easy setup with dip switchesand bottle jumpers, and an easily accessible integral setpoint dial. The PCM can also be configured for direct or reverse acting applications, includes high and low pressure,barbed connection ports, and can be conveniently poweredfrom a nearby 24 VDC power source. The PCM is perfect forcontrolling duct pressures, building pressurization, VFD control and many other common HVAC applications.