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BOILERPLATEPUBLISHED FOR EMPLOYEES, CUSTOMERS & SUPPLIERS OF PARKER BOILER CO. ISSUE NO 15 WINTER 98/ 99

HOT WATER SYSTEMS FOR HVACAND SOME COMMON PROBLEMS

1.) Hyundai, Korea

Dri ll ing Rig; two GO-4032 Hot Water Boilers

2.) Moscow, Russia

Ti re Recapping Plant, 50HP Steam Boiler

PARKER WORLDWIDE SALES UPDATE

SINGLE BOILER

HOT WATER

PIPING SYSTEM

The Parker T Model Hot WaterBoiler is used extensively in HVACfor providing hot water for spaceheating. There are many differenttypes of systems employed with ourboiler, which serve to heat the

building. Normally hot water sup-ply and return pipes are routedthrough the building and connectedto coils in terminal reheat units orfan coils.

The following is a discussion ofsome of the types of systems andadvantages and disadvantages asso-ciated with them as well as some of

the common problems, which wesee with boiler installations. Also,sequence of operation controlschemes are discussed.

One of the first considerations ofthe Design Engineer when design-ing a heating system is to determinethe tolerance for hot water tempera-ture fluctuation that his particular

system can tolerate.

The use of a hot water system in acommercial building does notrequire as tight a temperature con-trol as may be required in a clean

room or pharmaceutical facilitywhere temperature and humidityare critical.

CONTINUEDON PAGE

3.) Vi talizxadores Unidos, Guatemala

Central Ameri can Tire Recapping Co.

70 HP Oil Fired Boi ler

4.) Guaymas, Sonora, MexicoSonora Dry Cleaning 25 HP

Current Internati onal installation projects of the Parker Boiler Companynow in progress include:

PARKERB O I L E R C O.

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Most normal boiler operating con-trols have a built-in 8-12F differen-tial which means that hot watersupply temperatures will fluctuate.There are electronic controls avail-able which can control the differen-tial on the boiler to a tighter degree.

The diagram on the cover shows thesimplest type of boiler pipingschematic involving the boiler,expansion tank, air eliminator andpump. In this system water will

circulate continuously through theboiler at a rate which would bedependent upon the pump and theresistance of the system. It is alwaysadvisable to provide a bypass or athree way valve or valves in the sys-tem so that flow can be maintainedon the boiler.

On this type of system sometimesthe Design Engineer elects to install

outside air reset temperature con-trols and resetting of hot water sup-ply temperature can be accom-plished as part of the boiler control.However, we recommend a mini-mum return water temperature of120F to prevent condensation inthe boiler. This limits the low resethot water temperature point on thesystem.

A common system which we see inthe field utilizes a three way valve.This essentially cuts boiler flowand may allow only a small portionof the water to be routed throughthe boiler to mix with the returnwater and create a hot water supplytemperature to satisfy buildingneeds.

that we encounter in the field. Thefollowing are the problems that wenormally see.

PROBLEM #1: Lack of flow

through the boiler causing manualreset high limit shutdowns. Thisproblem can be addressed by pro-viding primary secondary pumpingin the design stage or providingthree way valves at the point of thewater use. If a three way valve isused at the boiler it is necessary toput a bypass around it or to put aminimum position stop on the

three way valve which will alwaysallow a certain amount of boilerwater flow. An alternate method isto install a run around pump on theboiler to maintain boiler water flow.

PROBLEM #2: Relief valve setting

too low. In many instances the specified boiler does not have a highenough relief valve to accommodatethe required system pressure. This is

the case when the boiler is providedat grade level or in the basementand the building has a height of twoor more stories. In this instance thestatic head of the water on the boil-er drives up the system and boilerpressure to a point where the reliefvalve cannot accommodate the pres-sure. In these instances it may berequired to change to a higher relief

valve setting to solve the problemand this can be quite difficultdepending on system componentsand proper procedures for ASME.Note that the maximun boiler pres-sure should be 25% below the reliefvalve set point, ( not less than 10psi ). The problem can also becaused by a high pressure pump,pumping into a boiler.

CONTINUEDFROMPAGE1 We see quite a few of these systemsin the field where the outside airresetting is accomplished by the useof a three way valve.

This system has the advantage of

being ableto reset the hot watersupply temperature to a tempera-ture lower than can be tolerated inthe boiler but it also creates lowflow problems in the boiler andmanual reset high limit shutdownswhen the boiler is allowed to expe-rience a low or no flow condition.

A preferable piping arrangementwhen low hot water system temper-atures are desired at times is a pri-mary secondary type of system. Inthis type of system a low headpump can be used on a boiler loopand a system pump can beemployed to provide water to thesystem. On the return line from thesystem there can be a three wayvalve which can blend in the desiredamount of return water to matchthe desired hot water supply tem-perature. Please contact us forsample piping diagrams.

These are the basic types of systems

HOT WATER SYSTEMS FOR HVACAND SOME COMMON PROBLEMS

New Area Code for Parker Boiler

213Area Code

818Area Code

626Area Code

562Area Code

310Area Code

New 323 ArNew 323 Area Codeea Code

New 323 ArNew 323 Area Codeea Code

Glendale

West HollywoodPasadenaEagleRock

City ofCommerce

BeverlyHills

Culver City

DowntownLosAngeles

Lynwood

HuntingtonPark

MontereyPark

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PROBLEM #3: Flue gas condensa-

tion. It is particularly important tomaintain the proper boiler watertemperature so as not to cause con-densation in the boiler. If thereturn water is too low coming intothe boiler the flue gases will con-dense dripping down onto the tubebundle causing problems with pilotoutages, corrosion and water on thefloor. We see this particularly inheat pump type applications. OurIndirect WH Model is the preferredunit for low temperature (

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5930 Bandini Boulevard, Los Angeles CA 90040

Fax (323) 722-2848

E-mail: sales@parkerboiler.com

Phone (323) 727-9800

visit our website atwww.parkerboiler.com

FABRICARE 98

Shown above, at the recentFabricare 98Show, at the AnaheimConvention Center, are Randy

Saxton, TomMcCook, Dean McCook and AdamMcCook of McCook Boiler & Pump Co. in Tucson, AZ.

McCook Boiler & Pump Co. has experienced an excellent sales year in1998 and they have recently taken on the responsibility of handlingContractor Sales in the Las Vegas area of Nevada. Their company, as wellas Parker Boiler, is looking forward to the increased business in the growing

Las Vegas area.

To our Customers and Suppliers:

Parker Boiler Co. has analyzed allof its products and found them tobe Year 2000 compliant. Thismeans that new products and thosein the field utilizing original factorysupplied controls will not have

their operation effected by the datetransition from 1999 to 2000.

We have also analyzed our internalbusiness systems including facili-ties, equipment and informationtechnology systems and have foundthe business will not experience anysignificant delay or interruption ofoperation as a result of the Year2000.

We believe our products and

Company will be ready for the nextmillennium.

Sincerely,

Sid D. DanenhauerPresident

Parker Boiler Company

YEAR 2000COMPLIANCE

BOILER

PARKERI N D USTR IAL