HS-501(A)

TEMPERATUREREGULATORSENGINEERING DATAMANUAL■ Application■ Selection■ Piping Diagrams■ Installation

ENGINEERING DATA

MANUALTEMPERATURE

REGULATORS

3

Introduction Temperature Regulator Functional Requirements 4

Chapter 1Explanation of Terms 5

Chapter 2Operating Principles and Component Selection 6

Self-Contained Vapor Tension

Temperature Regulator 6

Pilot-Operated Temperature Regulator 9

Pneumatic Regulator 11

Selection of Pneumatic Regulator 12

Chapter 34 Step Method for Sizing Temperature Regulators 14

Temperature Regulator Selection Guide 16

How to Determine Lbs./Hr. of Condensate 17

Properties of Saturated Steam Table 18

Temperature Conversion Chart 19

Steam Flow in Pipe Chart 19

ASHRAE Method for Sizing Return Lines 20

Chapter 4System Problems that Cause Poor Heating 21

Classification of Hot Water Heaters 22

Control Selection Guidelines 22

Classification of Types of Systems 23

Piping Diagrams 23

Contents

4

This manual is intended to serve as a guideto the proper selection, sizing andinstallation of temperature regulators. Thereare three types of regulators: self-containedvapor tension, pilot-operated and pneumatic-operated. Each has unique benefits andcharacteristics. Advantages anddisadvantages for each type are discussed.The types of temperature regulators are self-contained vapor tension, pilot operated andpneumatic operated. Each has uniquebenefits and characteristics. This manual isintended to illustrate the system advantagesand disadvantages of each type and to serveas a guide to proper sizing, selection andinstallation.

Temperature regulator installations vary fromsystems with large storage tanks that changetemperature gradually as hot water is drawnoff, to instantaneous shell and tube heatersthat lack storage tanks and require a fasttemperature response time.

Hoffman Specialty offers self-containedregulators as two-way temperature regulatorsto control the heating fluids or gases, andthree-way valves for mixing or diverting fluids.

Proper regulator selection, location andinstallation as well as correct sizing of themain valve are necessary to achieve propertemperature control. These steps also willhelp to maximize the life of the regulator. Inaddition, to achieve good temperature control,the sensing bulb must be properly locatedand installed. Other important factors inmaximizing overall system performance forsteam systems are proper trap sizing,location and installation.

Most complaints of poor temperature control can be traced back to improperselection or incorrect installation.

TemperatureRegulatorFunctionalRequirements

Introduction

Self-contained vapor tensiontemperature regulator

Pilot-operated temperature regulatorwith main valve and self-containedtemperature pilot

Pilot-operated temperature regulatorwith pneumatic temperature andpressure pilots

5

Here are definitions of the most popular termsused in temperature regulator control.

Air VentingAt start up, all steam-heated equipmentcontains air in the steam space. This must bevented before steam can enter. Usually, thesteam trap must be capable of venting air,particularly during start-up. Some types oftraps are better at venting air than others.

Differential PressureThere are two concerns regarding differentialpressure. The first is differential pressureacross the temperature regulator. This mayalso be referred to as pressure drop acrossthe regulator. It is the difference betweenupstream supply pressure and the pressuredownstream of the regulator. Obtaining goodtemperature control usually requires sufficientpressure drop to vary the amount of fluid orgas through the valve. Steam regulatorsshould normally allow a minimum of 50% ofthe supply pressure drop across the valve.With a 50% pressure drop, the regulator willutilize its full stroke and limit the condensingload during start-up (close to designcondition). Fluid regulators should normallyhave at least a 10 psi drop except on very lowpressure systems. Sizing for low pressuredrops on liquid valves increases the valve sizeand causes hunting (fluctuation) of the valve.

The second concern is differential pressureacross the steam trap. There must be apositive differential across the trap under alloperating conditions to allow drainage ofcondensate. If the system design does notprovide a positive differential pressure,condensate will back up into the steam spaceand cause cavitation (referred to as waterhammer, defined below). This can destroyregulators, traps and tube bundles.

All steam coils using modulating-typetemperature regulators must have gravitydrainage from the trap into a ventedcondensate return system. This should helpavoid problems like the ones we discuss next.

RecirculationOn systems without a storage tank, thesystem water is recirculated (pumped)continuously through the system andheater. Recirculation of the system wateracts as a buffer tank and helps preventsudden temperature changes from occurringat the regulator sensing bulb. A minimum of20% of system design flow is commonlyused to size the recirculating pump.

Water HammerIf a steam trap drains high temperaturecondensate into a low pressure wet return,flashing of the condensate may occur. Whenhigh temperature condensate at saturationtemperature discharges into a lower pressurearea, this flashing can create steam pocketsin the piping. When the latent heat in a steampocket is released, the steam pocketimplodes, causing cavitation (water hammer).The high forces (estimated to be in excess of5,000 psi) created by these implosions candamage the bellows, floats and copper tubingused in many steam traps, coils and forsystem piping.

Induced VacuumAs steam condenses back into condensate,its volume shrinks. This reduction in volumecan create pressures below atmospheric andis often referred to as induced vacuum. Aninduced vacuum inside a steam space cancause a negative differential pressure acrossthe steam trap and allow condensate to buildup. To assure positive differential pressure, avacuum breaker should be installed in thesteam coil or piping so air may enter andrelieve the vacuum. Complete condensatedrainage under all possible conditions must beprovided. This should prevent water hammerand coil freeze-up if condensate is held in thecoil by induced vacuum.

Modulating LoadsIn spite of changes in fluid flow rate orchanges in initial temperatures, temperatureregulators are often required to maintain aclose temperature range in the fluid beingheated. These changing conditions force theregulator to "modulate" (vary its valve open-ing) to meet the changing steam load. As aresult of this modulating, the steam pressuredownstream of the regulator changes. It variesfrom a high, when the fluid flow is at designconditions and the regulator is wide open, to alower pressure, perhaps even an induced vac-uum, when the regulator is partially closed.Vacuum breakers should be installed to openwhen the downstream steam pressure dropsbelow atmospheric pressure to allow air toenter the heat transfer device. Thus, theymaintain at least atmospheric pressure andassure that condensate continues to drainproperly.

Chapter 1

Explanation of Terms

6

Operation of Vapor Tension TemperatureRegulatorsThe vapor tension type temperature regulatoruses a sensing bulb filled under vacuum with avolatile fluid. This sensing bulb is connected toa bellows by a capillary tube that transmits thefluid to the bellows to operate the valve. Thesensing bulb is placed in the fluid where thetemperature is to be controlled. The vacuumholds the bellows in a compressed positionwhen the unit is cold. As the temperatureincreases, the volatile fluid will reach itssaturation temperature, begin to boil and createa vapor pressure inside the bulb. This vaporpressure formed in the top of the sensing bulbwill push fluid from the bottom portion of thebulb into the capillary tube and bellows. Thisexpands the bellows and closes the valve.

A heating regulator is held open by a spring andis closed by movement of the bellows. When thevolatile fluid is below its saturation temperature,the vacuum inside the bulb pulls the bellowsaway from the valve stem. Different fluids withvarious boiling points are used to obtain varioustemperature ranges. Hoffman Specialty Series1140 temperature regulators, for example,provide 40 degrees F. temperature adjustmentfor each range. Ranges are available for 40degrees F. to 220 degrees F.

For cooling applications, the valve plug is initially closed by the spring pressure. As thetemperature increases, the vapor pressure inthe bulb pushes fluid through the capillary andexpands the bellows and opens the valveagainst the spring force.

Hoffman 1140 temperature regulators areavailable for both heating and coolingapplications. There are several body typesavailable for various applications.

Advantages of self-contained regulators• Completely self-contained unit does

not require external power supply.• Modulates to handle wide range of

system loads.• Easy temperature adjustment.• Relatively inexpensive in comparison to

other types of temperature control.• Normally open valve requires minimum

pressure drop for low pressure systems.Disadvantages due to system characteristics

• Primary failure mode is open forheating regulators and closed forcooling regulators.

Primary Applications• Storage tanks• Mixing of hot and cold water where

constant recirculation can be provided.• Shell and tube heat exchangers if loads

are constant or if buffer tank is used to smooth out load changes.

• Aftercoolers• Engine jacket cooling• Air heat coils

Series 1140 Self-Contained Vapor Tension TypeThe 1140 Series offers a choice of 7 bodystyles for heating or cooling. Here is adescription of each body type with advantages,disadvantages and primary applications. In mostapplications, more than one type can be used. Ifso, economics or availability often determineswhich valve to specify.

OperatingPrinciplesandComponentSelection

This chapter discussesoperating principles foreach of the three typesof temperature regula-tors commonly used inHVAC temperature con-trol. The three types areself-contained vapor ten-sion type, pilot-operatedtype and pneumatictype. Selection of bodytypes and componentsalso is discussed foreach of the three regula-tor types.

Self-Contained Vapor Tension Type Temperature Regulator

SENSING BULB

CAPILLARY

SPRING

Valve in open position. Bulbbelow set point.

BELLOWS

SENSING BULB

VAPORPRESSURE

CAPILLARY

SPRING

Valve in closed position. Bulbabove set point.

Chapter 2

HEATING APPLICATION HEATING APPLICATION

The 03 uses a balance piston to provide tight shutoff against high differential pressures.The balance piston is designed for steam serviceonly. Results will be poor on water service, as ittakes a long time for water to bleed from thebalance chamber. The 03 is preferable for highpressure steam systems requiring tight shut off(dead end service).

The 05 is a double-seated valve with stainlesssteel plug and seat. Double-seated valves do nothave a tight shut off. The allowable leakage rate ona new double seated valve is .01%. Double-seatedvalves allow high capacity as they provide two flowpaths around the seats, but they should not beused on systems that may overheat due to seatleakage. They also are pressure balanced and mayoperate against high differential pressures. The 05may be used on steam or water service.

The 01 body code has a single seat compositiondisc, provides tight shut off and may be used onsystems requiring dead end service. This discprovides the best service on water systems whichmay contain dirt or scale, and it is easily replaced.The valve has a brass seat and should not be usedon service where the differential pressure exceeds50 psi. The 01 body code is the least expensiveselection.

The 02 is a single, stainless steel seat that alsoprovides tight shut off and is good for dead endservice. The stainless steel seat provides long lifeand is recommended for steam service. The singleseated valve limits the maximum pressuredifferential, particularly on larger sizes. When thedifferential pressure rating is exceeded, theactuator may not have enough power to close theplug against the system pressure.

7

• Steam or Water Service—Positive deadend service

• Single Seat, CompositionDisc, Bronze Trim—Bronze integral seat

• Body—Bronze, union ends•Maximum Differential

Pressure:1⁄2"(15mm)—50 psi (3.5 bar)3⁄4"(20mm)—50 psi (3.5 bar)1”(25mm)—32 psi (2.2 bar)

11⁄4"(32mm)—20 psi (1.4 bar)11⁄2"(40mm)—16 psi (1.1 bar)2"(50mm)— 8 psi.(.56 bar)

• Steam Service—Dead end service up to fullallowable body steampressure

• Balanced Single Seat, Stainless Steel Trim—Remov-able stainless steel seat, discand balancing piston

• Body—3⁄4"(20mm) through 2"(50mm)– bronze body, union ends

•Maximum DifferentialPressure:

3⁄4"(20mm)— 250 psi (17.2 bar)1"(25mm)—200 psi (13.8 bar)

11⁄4"(32mm)—200 psi (13.8 bar)11⁄2"(40mm)—200 psi (13.8 bar)2"(50mm)—150 psi.(10.3 bar)

Body Code 01

Body Code 02 • Steam or Water Service—Dead end shut-off, wherehigher temperatures andpressures prevail

• Single Seat, StainlessSteel Trim—1⁄2" (15mm)–Removable stainless steelseat and cone disc. 3⁄4"(20mm)through 2"(50mm)–Integralstainless steel seat ring andbottom guided stainless steelseat disc

• Body—Bronze, union ends• Maximum Differential

Pressure:1⁄2"(15mm)—125 psi (8.6 bar)3⁄4"(20mm)— 60 psi (4.2 bar)1"(25mm)— 32 psi (2.2 bar)

11⁄4"(32mm)— 20 psi (1.4 bar)11⁄2"(40mm)— 16 psi (1.1 bar)2"(50mm)— 8 psi.(.56 bar)

• Steam or Water Service—• Double Seat, Stainless

Steel Trim—Stainless steelseat rings and stainless steelcenter-guided plunger.

• Body—3⁄4"(20mm) through2"(50mm)—bronze, union ends.21⁄2"(65mm) through 4”(100mm)—Iron body, flanged, faced anddrilled for 125 Ibs. (8.6 bar)standard.

• Maximum Differential Pressure:3⁄4"(20mm)—250 psi (17.2 bar)1"(25mm) — 11⁄2"(40mm) —

200 psi (13.8 bar)2"(50mm)— 150psi (10.3 bar)

21⁄2"(65mm) — 4"(100mm) —125 psi (8.6 bar) (iron body,flanged)

Body Code 05

Body Code 03

Direct-Acting(A rise in temperature closes the valve.)

The 06 three-way valve may be used as amixing or diverting valve on water systems.The valve has 3 ports, each designated A, Bor C. Port "A" on the bottom of the valve isthe mixed water outlet. Port "B" is the hotwater inlet, and port "C" is the cold waterinlet. A sliding cylinder is used to direct flowfrom the hot or cold port. When 06 is used asa mixing valve, hot water enters port B andflows under the cylinder. Cold water entersport C above cylinder. The cylinder hasopenings to allow flow through the piston intothe mixed port A. The blended temperatureexits through the bottom opening. When usedas a diverting valve, fluid enters through A. Ifit is below the set point, it discharges underthe cylinder to B. If above the set point, itexits through the cylinder to C. As the valvemodulates within the control range, fluid maydischarge through both side openings.The 06 provides tight shut off and may beused where dead end service is required.

The 02R is a single seated reverse-actingvalve for cooling applications. The stainlesssteel seat provides long life. This is a goodselection when differential pressures arewithin the limitations shown in thedescription.

The 05R is a double-seated valve with astainless steel plug and seat. The allowableleakage rate on a new valve is .01%. Double-seated valves should not be used in no flowconditions, and they do not have a tight shutoff.

8

Reverse-Acting(A rise in temperature opens the valve.)

Three-Way Mixing orDiverting Valves

Body Code 02R • Steam or Water Service—General cooling service where dead end shut-off isrequired

• Single Seat, Stainless Steel Trim—Stainlesssteel seat ring and bottom-guided stainlesssteel disc

• Body—Bronze, union ends3⁄4"(20mm) through2"(50mm)

• Maximum DifferentialPressure:

1⁄2"(15mm)—125 psi (8.6 bar)3⁄4"(20mm)— 60 psi (4.2 bar)1"(25mm)— 32 psi (2.2 bar)

11⁄4"(32mm)— 20 psi (1.4 bar)11⁄2"(40mm)— 16 psi (1.1 bar)2"(50mm)— 8 psi (.56 bar)

• Steam or WaterService—

• Stainless Steel Trim—Stainless steel centerguided plunger

• Body—3⁄4"(20mm) through2"(50mm)—bronze, union ends. 21⁄2"(65mm) through4"(100mm)—Iron body,flanged, faced and drilledfor 125 lbs. (8.6 bar)standard

•Maximum Differential Pressure:

3⁄4"(20mm)—250 psi (17.2 bar)1"(25mm) — 2"(50mm)—

200 psi (13.8 bar)21⁄2"(65mm) — 4"(100mm)—

125 psi (8.6 bar)(iron body flanged)

Body Code 06

• Water Service Only•Nickel Plated Piston,

Bronze Trim—Sliding piston with nickel plated surface and bronze seatingsurfaces

• Body— 1⁄2"(15mm) through 2"(50mm)—bronze, union ends, bottom connection screwed 21⁄2"(65mm) through 4"(100mm)—Ironbody, flanged, faced and drilled for 125lb. (8.6 bar) standard

•Maximum Differential Pressure: 1⁄2"(15mm) — 3⁄4"(20mm)—

250 psi (17.2 bar)1"(25mm) — 2"(50mm)—

200 psi (13.8 bar)21⁄2"(65mm) — 4"(100mm)—

125 psi (8.6 bar)

Body Code 05R A

BC C B

A

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Pilot-operated main valve with liquidexpansion temperature pilot

A pilot-operated valve has a separate mainvalve. The main valve is a normally closeddevice. It is opened by a temperature pilotwhich loads steam pressure on the mainvalve diaphragm. This force pushes against aspring and the main valve opens.

The temperature pilot used on the Series2000 valve, for example, operates on theliquid expansion principle. It has a fluid-filledsensing bulb connected to a bellows by acapillary tube. As the fluid inside the bulb isheated, it expands and is transmitted throughthe capillary to a bellows. The bellowsexpands to operate the pilot valve.

Advantages of pilot-operated main valves• Pilot-operated valves may be

combined with pressure pilots orsolenoid pilots to provide multiplefunctions or safety overrides.

• Modulate to handle wide range of system loads.

• Response time is somewhat faster than vapor tension types due to smaller bulb.

• Liquid expansion pilot has a wide range temperature adjustment.

• Operate against high differentialpressures.

• Provide in excess of 100 degrees F over temperature protection in temperature pilot.

Disadvantages• Normal failure mode of pilot is

fail open, while failure mode of main valve is closed.System can be protected by solenoid overrides wired into aquastats, flow switches or auxiliary contacts.

• Used on steam service only.• Require higher pressure drops

to open main valve than self-contained regulator.

Primary Applications• Storage tanks• Shell and tube heaters where

loads are constant or wherebuffertank is used to smooth outload changes.

• After coolers• Applications requiring pressure

and temperature control.• Applications requiring solenoid

pilots to override for automaticshut down and start up.

• Where safety overrides arerequired.

The Hoffman Specialty Series 2000 lineincludes 27 main valves with 14 pilots andhundreds of possible combinations to cover awide range of temperature, pressure andcapacity options.

Pilot-Operated Temperature Regulator

The main body of the pilot-operated valve isa single-seated, normally closed design.The valve is held in the closed position by aspring and opened by applying steampressure to the 2-ply stainless steeldiaphragm. Main valves are available in1/2" through 6" sizes. Each size has achoice of three port and seat sizes to meetsystem conditions. Full port providesmaximum capacity. Port and seat sizes maybe interchanged in the field to meetchanging conditions.There are several types of pilots that maybe used separately or in conjunction withother pilots to operate the main valve. The main valve is designed for steamservice only.

10

A self-contained temperature pilot controlsthe main valve. The temperature pilotoperates on the liquid expansion principle.The pilot valve controls steam flow from theupstream supply side of the main valve tothe diaphragm of the main valve.Temperature adjustment is made by turningthe adjusting knob. The temperature pilotmay be used in conjunction with a springpressure pilot to control both temperatureand pressure. It also may be used with asolenoid pilot to provide automatic shut-down when over-temperature occurs. Normalfailure of the temperature pilot is to fail open.

When the temperature or pressure pilotcloses, steam flow to the diaphragm is shutoff. The steam trapped on the main valvediaphragm bleeds off through a bleed orifice,allowing the main valve to close.

The pilot responds more positively and fasterthan the self-contained vapor tension typeregulator.

Selection of Pilot-Operated Temperature Regulator

Normally closedstainless steel seat and plug

Stainless steel stem withbronze guide bushings

Alloy steel return springisolated from flow path

Large unrestricted flowareas for high capacity

Packless construction

INLETOUTLET

Two-ply stainlesssteel diaphragm

Armored capillary

Knob cover designed for lowheat transfer

Liquid expansionnon-toxic fill

Overheat protectionmechanism

Adjustable pointer

Calibrated temperaturescale

Protective sleeve

Locking set screw

Corrosion-resistantbrass sleeve reduces

galling

Bellows seal eliminatespacking

TEMPERATURE PILOT

MAIN VALVE

11

OperationPneumatic temperature pilots open or closewith a modulated air signal to the regulator.As the brass bulb heats or cools, itexpands or contracts to operate a valvecontrolling the air signal. These pilotsprovide fast response to a minimumtemperature change. The pneumatic airpilot should be used where closetemperature control is critical.

Pneumatic temperature pilots may be usedwith diaphragm valves to controltemperature only. Or, they may be usedwith the Hoffman Specialty Series 2000pilot operated valves to provide bothtemperature and pressure control.

Advantages of pneumatic-operated valves• Selection of components can

provide either fail open or fail closed design.

• Provide fast response over a minimaltemperature change.

• Easily adjusted.• No limit to fixed length of capillary.• Not affected by ambient temperature.

Disadvantages• More costly than self-contained

valves.• Will not operate if air supply

is interrupted.

Applications• Storage tanks• Instantaneous heaters• Duct heaters• Shell and tube heat exchangers• After coolers• Engine jacket cooling• Process temperature control

Pneumatic-Operated Temperature Regulator

Port for downstream outletpressure feedback

12

This type of regulator is recommendedwhen rapidly changing load conditionsoccur. When a Hoffman pneumatic air pilotis used to control a Hoffman Series 2000main valve, it is normally used inconjunction with a pneumatic pressure pilotsuch as a Hoffman Model AP-1A.

The pneumatic temperature pilot regulatestemperature through the use of a bimetalsensing device. When supplied with an 18psi air signal, it provides a 3 to 15 psioutput supply. The air supply signal to theair pilot may be up to 36 psig. With a 36psig signal, the output supply will be from 6psig to 30 psig.

Combining a temperature pilot and apressure pilot also controls downstreampressure. The pressure downstream of themain valve is connected to the downstreampressure feedback port on the air pressurepilot. Feedback is sensed on the undersideof the diaphragm, and air supply pressureis connected to the top of the diaphragm.The air pressure pilot begins to open with 9psi air loading pressure, and thedownstream pressure is limited to air

loading pressure minus 9 psi. Themaximum output steam pressure with a 15psi air supply to the pilot is 6 psig. Byincreasing the air signal to 30 psig, themaximum steam output from the mainvalve (Series 2000) is 21 psig. A Series2000 valve using a 315 PNT and an AP-1Asupplied with a 18 psig signal will strokefrom fully open to fully closed within anaccuracy of 5 degrees F.

When downstream steam pressures ofmore than 21 psig are required, an AP-4Apneumatic pressure pilot may be used. Thisis because the AP-4A begins to open at 9psig of air pressure.

Using a Series 2000 valve with a 315 PNTand an AP-4A, outlet pressures up to 84psig can be obtained. This is calculated asfollows: Subtract the 9 psi spring force fromthe air signal and multiply by the 4:1 ratioproduced by the AP-4A with a 15 psi signal.The pressure limit in this example is airsupply (15 psi) minus spring force (9 lbs.)times the ratio (4:1) equals 24 psi outletsteam pressure.

Selection of Pneumatic-Operated Temperature Regulators

13

A pneumatic air pilot may be used with adiaphragm control valve to maintaintemperature. The diaphragm valve is not apressure limiting device and can be usedwhen high pressures are required on criticaltemperature applications.

By selecting normally open or normallyclosed diaphragm valves and properlyconnecting the direct or reverse-actingsupply port, systems can be designed tofail open or fail closed for either heating orcooling applications.

DIAPHRAGMVALVE

AIRFILTER

REGULATOR

PNEUMATICTEMPERATURE

PILOT

14

Step 1.Determine the heating medium to be used(steam, water, etc.) and measure the avail-able supply pressure. Note that the systemdesign operating pressure often is not theavailable pressure at the regulator. This isimportant particularly on low pressuresystems that may have significant frictionloss in the piping. Pressure readings shouldbe taken near the regulator installation site.

Note:On steam regulators, system efficiency andtemperature control are improved by operat-ing at a low steam pressure. When thesystem load is to be heated to less than200 degrees F., use a 15 psig or lowersteam supply. Install a steam pressurereducing valve, if necessary. Low pressuresteam will minimize the condensate tem-perature discharged from the steam trapand will reduce the flash steam losses inthe return system. This will improve the lifeof the condensate return pump and seal,and it will improve the temperature control.Because of the wide temperature differencebetween the steam and the medium beingheated, temperature variations increasewhen a higher pressure/higher temperaturesteam supply is used. Re-evaporation offlash steam losses are reduced approxi-mately 1% for every 10-degree reduction incondensate temperature. The operatingcost to heat water to 180 degrees F. to use5 psi steam is approximately 12% less thanusing 100 psi steam, unless the energy inthe flash steam is recovered.

Step 2.Select an outlet pressure. There must be apressure drop across the temperature regu-lator. Then the heating coils can be sizedbased on this outlet pressure. For bestcontrol on steam regulators, the pressuredrop should be at least 50% of the supplypressure to allow for good modulation of thevalve (for example, 90 psi supply steamshould be reduced to 45 psi or less).Temperature regulators controlling liquidflow should have a 10 to 20 psig pressuredrop for optimum control.

Step 3.Determine load requirements. The capacitymay be calculated using the "Helpful Hints"on page 15. Note that steam regulator sizesare based on pounds per hour. Liquid regula-tors are based on gallons per minute flowrate.

The capacity requirement should be basedon maximum expected load requirements.Then the regulator should be sized as closeto this actual requirement as possible.Oversized valves will have greater tempera-ture variations and often tend to hunt.Safety factors should not be included incalculation of actual load conditions.

Step 4.Select the temperature regulator. Things toconsider include capillary lengths, supplypressure, dead end service, allowableresponse time and allowable temperaturevariation. Also consider what type of applica-tion is required – heating, cooling, mixing ordiverting. Select a standard temperaturerange that will operate close to the mid-pointon the regulator. For vapor tension type regu-lators, it is better to operate in the upper50% of the range rather than the lower 50%.Liquid expansion and pneumatic regulatorsoperate equally throughout their entire tem-perature ranges.

Note:Self-contained regulators or pilots mayrequire 10 to 80 seconds to respond to atemperature change. This will vary depend-ing on size, range and degree of change,although this is usually not a problem onsystems with a storage tank. On systemswithout a storage tank, this can causemomentary temperature fluctuations untilthe regulator stabilizes to a changing condition.

Four-StepMethod forSizingTemperatureRegulators

Chapter 3

15

Pneumatic regulators respond faster andhold a closer temperature range. However,like the other types, they do not have animmediate response. The design of criticalapplications should always include a systemstorage tank to act as a buffer. Also, makesure the sensing bulb material is compatiblewith the medium being controlled, and con-sider specifying a separable well. (A separa-ble well allows the sensing bulb to beremoved from the system fluid stream with-out draining the system itself. Separable wellsare optional and must be ordered separately).

Helpful Hints and Formulas -Approximating Steam Loads

• Heating water with steam(Lbs./hr. required = GPM divided by 2 xtemp rise degrees F.)

• Heating fuel oil with steam(Lbs./hr. required = GPM divided by 4 xtemp rise degrees F.)

• Heating air with steam coils(Lbs./hr. required = CFM divided by 900 x temp rise degrees F.)

Sizing a Regulator – An ExampleA shell and tube heat exchanger is requiredto increase the temperature of 40 GPMwater from 40°F. to 120°F. Available steamsupply is 100 psig. Select a temperatureregulator.

Step 1. Determine medium and available supplypressure. All required data has beencollected.

Step 2.Select operating pressure of heatexchanger. This should be at least one-halfof the steam supply (or 50 psi). However,at 50 psi, the condensate temperaturefrom the trap will be approximately 298°F.having about 9% flash loss. Heating thewater to 120°F. utilizing low pressure steamwill save flash losses. Choosing a 5 psiheat exchanger will drain condensate at227°F. and flash loss will be only about1.5%. While this may require a larger heatexchanger, the saving in energy can payback initial cost in a short time. By usinglow pressure steam, the temperature regu-lator and steam trap will be less expensiveand often will recapture the additional costof the heat exchanger.

Step 3.Determine load requirements.Estimating the steam load using the helpfulhints (above) GPM/2 x temperature rise =lbs./hr., or 40/2 x 80 = 1600 lbs./hr.steam required.

Step 4.Select actual temperature regulator.To control the 120°F. temperature and limitthe steam to 5 psig in the heat exchangershell, choose a Series 2000 regulator withtemperature and spring pilots.A Series 2000 with one-inch main valvesize will pass 1850 lbs./hr. of steam with100 in and 5 psi out. Refer to HoffmanSpecialty’s General Catalog, HS-900, whichprovides capacity tables to assist withproper selection.

Since the heat exchanger shell is limited to5 psi, use a trap rated for 15 psi differen-tial. This should be based on a minimumload of 1850 lbs./hr. at 1/2 psi differentialpressure. A safety factor of 1.5 times thecalculated load should be applied to thesteam trap. This will assure completedrainage of the condensate under all oper-ating conditions and during heavy start-uploads. This could be a 2-inch modelFT015H (actually this trap will pass 3150lbs./hr. at 1/2 psi differential).

If ignoring the energy savings from reducedflash, use a 1-inch Series 2000 main valvewith temperature pilot only. In this case,the pressure in the heat exchanger shell isnot limited and could reach 100 psi. Thetrap then must be able to operate with 100psi differential. Use a high capacity 2-inchmodel FT125X steam trap.

A Model 1140 temperature regulator couldbe used and not limit the pressure in theheat exchanger shell. A 1 1/4 inch 1140with 03 body code will pass 2220 lbs./hr.With the 1140, a trap able to operate with100 psi differential is required. The highcapacity 2-inch model FT125X F&T trap canalso be used.Note: Assume a steam cost of $7.50 per 1,000lbs. and a load of 1400 lbs./hr. in theabove selection. The comparable savingsbetween 50 psi steam flash at 9% and the5 psi flash loss of 1.5% is $0.79 per hour.This could amount to $6,898.00 per year,based on continuous operation of the unit.

16

Temperature Regulator Selection Guide

Direct Regulators PneumaticRegulators

• 315 PNT Temp. Pilot• Diaphragm Valve with

3-15 Signal

TemperatureControl Only

Temperature & Pressure Control

Series 1140Self

ContainedRegulators

Series 2000• Main Valve• STPA Temp.

Series 2000• Main Valve• TP-A Pilot• SP Pilot

Up to 21 PSIOutletSteam

For 0 to 84PSI Outlet

Steam

Series 2000• Main Valve• AP-1A Pilot• Air PRV

Series 2000• Main Valve• AP-4A Pilot• Air PRV

Temperature Control Only

Temperature &Pressure Control

Notes:1. Maximum pressures shown for pneumatic regulators are

based on 36 psi supply to the 315 PNT which will result in a 6-30 psi output signal.

2. All Series 2000 valves may have solenoid pilots added for override safety control.

17

Properties of Saturated Steam

How to Determine Pounds per Hour of Condensate1. Steam heats a liquid indirectly through a

metallic wall.• Cooking coils• Storage tanks• Jacketed kettles• StillsLbs./hr. condensate =

Ql x 500 x Sg x Sh x (T2-T1)L

When:Ql = Quantity of liquid being heated in gal/minSg = Specific gravity Sh = Specific heat L = Latent heat in Btu/lb.500= Constant for converting gallons per minute to pounds per hour.T2 = Final temperature T1 = Initial temperature

2. Steam heats air or a gas indirectly through a metallic wall• Plain or finned heating coils • Unit space heaters Lbs./hr. condensate =

Qg x D x Sh x (T2-T1) x 60L

When: Qg = Quantity of air or gas in ft3/min D = Density in Ib/ft3

Sh = Specific heat of gas being heated T1 = Initial temp. T2 = Final temp. L = Latent heat in Btu/lb. 60 = Minutes in hour

3. Steam heats a solid or slurry indirectly through a metallic wall• Clothing press• Cylinder driers • Platen presses Lbs./hr. condensate =

970 x (W1-W2) + W1 x (T2-T1) L x T

When: W1= Initial weight of product W2= Final weight of product T1 = Initial temp. T2 = Final temp. L = Latent heat in Btu/lb.T = Time required for drying (hours)Note: 970 is the latent heat of vaporization at atmospheric pressure. It is included because the drying process requires that all moisture in the product be evaporated.

4. Steam heats a solid through direct contact• Sterilizers • Autoclaves Lbs./hr. condensate =

W x Sh x (T2-T1)L x T

W = Weight of material being heated in Ibs. Sh = Specific heat of material being heated T1 = Initial temp.T2 = Final temp. L = Latent heat Btu/lb. T = Time to reach final temp. (hours)

The Properties of Saturated Steam tableshows the relationship between temperatureand pressure. The table also provides Btuheat values of steam and condensate atvarious pressures and shows the specificvolume of steam at various pressures.

Definitions:Saturated Steam: Pure steam at thetemperature corresponding to the boilingpoint of water.

Pressure Psi (Gauge): Gauge pressureexpressed as Ibs./sq. in. The pressureabove that of atmosphere. It is pressureindicated on an ordinary pressure gauge.

Sensible Heat: Heat which only increasesthe temperature of objects (as opposed tolatent heat). In the saturation tables, this isthe Btu remaining in the condensate atsaturation temperature.

Latent Heat: The amount of heat expressedin Btu required to change 1 Ib. of water atsaturation temperature into 1 Ib. of steam.This same amount of heat must be given offto condense 1 Ib. of steam back into 1 Ib.of water. The heat value is different for everypressure-temperature combination shown .

Total Heat: The sum of the sensible heat inthe condensate and the latent heat. It is thetotal heat above water at 32° F.

Specific Volume cu. ft. per lb.: The volumeof 1 Ib. of steam at the correspondingpressure.

See Properties of Saturated Steam table onthe following page.

Specific Heat Content LatentPressure Saturated Volume Btu per Ib. Heat of

PSI Temp cu. ft. Saturated Saturated Vaporization(Gauge) ° F. per Ib. Liquid Vapor Btu per Ib.

150 366 2.75 337 1196 858155 368 2.67 340 1196 854160 370 2.60 342 1196 854165 373 2.53 345 1197 852170 375 2.47 347 1197 850175 378 2.40 350 1198 848180 380 2.34 352 1198 846185 382 2.29 355 1199 844190 384 2.23 357 1199 842195 386 2.18 359 1199 840200 388 2.14 361 1199 838210 392 2.05 365 1200 835220 396 1.96 369 1200 831230 399 1.88 373 1201 828240 403 1.81 377 1201 824250 406 1.75 380 1201 821260 410 1.68 384 1201 817270 413 1.63 387 1202 814280 416 1.57 391 1202 811290 419 1.52 394 1202 807300 421 1.47 397 1202 805325 429 1.37 405 1202 797350 436 1.27 412 1202 790375 442 1.19 419 1202 782400 448 1.09 426 1202 774425 454 1.06 432 1202 770450 459 .972 438 1202 761475 465 .948 444 1202 757500 469 .873 449 1201 748525 475 .850 455 1201 746

550 480 .820 461 1200 740575 485 .784 466 1200 734600 490 .733 472 1199 727625 493 .721 476 1198 723650 498 .692 481 1197 718675 502 .645 485 1197 712

700 505 .642 490 1195 703750 513 .598 498 1195 697800 520 .555 514 1194 680850 527 .521 523 1193 670900 534 .489 532 1192 661950 540 .462 540 1191 651

1000 548 .435 547 1189 6421050 553 .413 550 1187 6371100 558 .390 564 1185 6211150 563 .372 572 1183 6121200 567 .353 579 1182 6031300 579 .322 593 1176 5831400 588 .295 606 1172 5651500 597 .271 619 1167 5481570 604 .2548 624 1162 5381670 613 .2354 636 1155 5191770 621 .2179 648 1149 5011870 628 .2021 660 1142 4821970 636 .1878 672 1135 4632170 649 .1625 695 1119 4242370 662 .1407 718 1101 3832570 674 .1213 743 1080 3372770 685 .1035 770 1055 2852970 695 .0858 801 1020 2193170 705 .0580 872 934 62

Specific Heat Content LatentPressure Saturated Volume Btu per Ib. Heat of

PSI Temp cu. ft. Saturated Saturated Vaporization(Gauge) ° F. per Ib. Liquid Vapor Btu per Ib.

0 212 26.8 180 1150 9701 215 24.3 183 1151 9672 218 23.0 186 1153 9653 222 21.8 190 1154 9634 224 20.7 193 1155 9615 227 19.8 195 1156 9596 230 18.9 198 1157 9587 232 18.1 200 1158 9568 235 17.4 203 1158 9559 237 16.7 205 1159 953

10 239 16.1 208 1160 95211 242 15.6 210 1161 95012 244 15.0 212 1161 94913 246 14.5 214 1162 94714 248 14.0 216 1163 94615 250 13.6 218 1164 94516 252 13.2 220 1164 94317 254 12.8 222 1165 94218 255 12.5 224 1165 94119 257 12.1 226 1166 94020 259 11.1 227 1166 93925 267 10.4 236 1169 93330 274 9.4 243 1171 92635 281 8.5 250 1173 92340 287 7.74 256 1175 91945 292 7.14 262 1177 91450 298 6.62 267 1178 91155 302 6.17 272 1179 90760 307 5.79 277 1181 90365 312 5.45 282 1182 90070 316 5.14 286 1183 89775 320 4.87 290 1184 89380 324 4.64 294 1185 89085 327 4.42 298 1186 88890 331 4.24 301 1189 88795 334 4.03 305 1190 884

100 338 3.88 308 1190 882105 341 3.72 312 1189 877110 343 3.62 314 1191 877115 347 3.44 318 1191 872120 350 3.34 321 1193 872125 353 3.21 324 1193 867130 355 3.12 327 1194 867135 358 3.02 329 1194 864140 361 2.92 332 1195 862145 363 2.84 335 1196 860

Specific Heat Content LatentVacuum Saturated Volume Btu per Ib. Heat ofInches of Temp cu. ft. Saturated Saturated VaporizationMercury ° F. per Ib. Liquid Vapor Btu per Ib.

29 79 657.0 47 1094 104727 115 231.9 83 1110 102725 134 143.0 102 1118 101720 161 74.8 129 1130 1001

15 179 51.2 147 1137 99010 192 39.1 160 1142 9825 203 31.8 171 1147 9761 210 27.7 178 1150 971

18

STEAM BELOW ATMOSPHERIC PRESSURE STEAM ABOVE ATMOSPHERIC PRESSURE (Cont.)

STEAM ABOVE ATMOSPHERIC PRESSURE

Properties of Saturated Steam

Fluid Pressure PSI (Gauge) Service Velocities—FPM

SATURATED STEAM 0-15 Heating Mains 4000-6000SATURATED STEAM 50-up Miscellaneous 6000-8000SUPERHEATED STEAM 200-up Turbine and Boiler Leads 10000-15000

WATER 25-40 City Service 120-300WATER 50-150 General Service 300-600WATER 150 Boiler Feed 600

Pipe Size PRESSURE PSI (GAUGE)(Inches) 5 10 15 30 50 75 100 125 200 250

1⁄2 30 40 45 60 90 120 150 180 270 3303⁄4 55 70 80 110 160 220 280 340 510 620

1 90 110 125 180 270 390 460 560 840 102011⁄4 160 200 225 325 480 650 820 990 1490 183011⁄2 220 270 300 450 660 900 1100 1300 2060 2550

2 370 455 520 750 1100 1500 1900 2300 3450 420021⁄2 525 650 750 1050 1600 2175 2750 3300 4950 60503 800 950 1350 1600 2500 3350 4250 5150 7700 945031⁄2 1100 1350 1550 2200 3400 4550 5700 6900 10200 127004 1450 1800 2000 2900 4300 5850 7400 8900 13450 16400

5 2300 2800 3200 4600 6800 9300 11700 14100 21200 260006 3200 3900 4500 6400 9800 13200 16800 20300 30800 369008 5700 7000 8000 11400 17100 23300 29300 35400 53100 65200

10 9300 11400 13000 18900 28100 38000 48100 58100 87100 10650012 13500 16600 18900 27000 40700 55300 69700 84200 126500 154700

°F -112 -76 -40 -4 14 32 50 68 104 140 176 212 248 284 320 356 392 428 464 500➔ -80 -60 -40 -20 -10 0 10 20 40 60 80 100 120 140 160 180 200 220 240 260°C -62 -51 -40 -29 -23 -17.7 -12.2 -6.6 4.4 15.6 26.8 37.7 49 60 71 83 93 104 115 127

536 572 608 644 680 716 752280 300 320 340 360 380 400138 149 160 171 182 193 204

TEMPERATURE CONVERSIONS—° F and ° CEnter table at arrow. Numbers in bold type in center of table refer to either ° C or ° F, whichever is being converted into the other scale. Ifconverting from ° C to ° F, equivalent temperature is found in upper section. If converting from ° F to ° C, answer is found in lower section.

REASONABLE VELOCITIES FOR FLUID FLOW THROUGH PIPES

LBS./HR. SATURATED STEAM AT 6000 FT./MIN. velocity in iron or steel pipe

Steam Flow in Pipes

19

Flow Rate Supply Pressure= 100 psig(lbs./hr.) Return Pressure=0 psig

p/L, psi/100 ft.PipeSize(in.)

1⁄161⁄4 1

1⁄2 28 62 1333⁄4 62 134 290

1 120 260 544

11⁄4 250 540 1130

11⁄2 380 810 1700

2 750 1590 a

21⁄2 1200 2550 a

3 2160 4550 a

4 4460 9340 a

6 13,200 a a

8 27,400 a a

Flow Rate Supply Pressure= 150 psig(lbs./hr.) Return Pressure=0 psig

p/L, psi/100 ft.PipeSize(in.)

1⁄161⁄4 1

1⁄2 23 51 1093⁄4 50 110 230

1 100 210 450

11⁄4 200 440 930

11⁄2 310 660 1400

2 610 1300 a

21⁄2 980 2100 a

3 1760 3710 a

4 3640 7630 a

6 10,800 a a

8 22,400 a a

Flow Rate Supply Pressure= 100 psig(lbs./hr.) Return Pressure=15 psig

p/L, psi/100 ft.PipeSize(in.)

1⁄161⁄4 1

1⁄2 56 120 11003⁄4 120 260 2400

1 240 500 4540

11⁄4 500 1060 9500

11⁄2 750 1600 14,200

2 1470 3100 a

21⁄2 2370 5000 a

3 4230 8860 a

4 8730 18,200 a

6 25,900 53,600 a

8 53,400 110,300 a

Flow Rate Supply Pressure= 150 psig(lbs./hr.) Return Pressure=15 psig

p/L, psi/100 ft.PipeSize(in.)

1⁄161⁄4 1

1⁄2 43 93 2003⁄4 93 200 420

1 180 390 800

11⁄4 380 800 1680

11⁄2 570 1210 2500

2 1120 2350 4900

21⁄2 1800 3780 7800

3 3200 6710 a

4 6620 13,800 a

6 19,600 40,600 a

8 40,500 83,600 a

Flow Rate Supply Pressure= 30 psig(lbs./hr.) Return Pressure=0 psig

p/L, psi/100 ft.PipeSize(in.)

1⁄161⁄4 1

1⁄2 60 130 2743⁄4 130 280 590

1 250 530 1120

11⁄4 520 1110 2340

11⁄2 780 1670 3510

2 1540 3270 a

21⁄2 2480 5250 a

3 4440 9360 a

4 9180 19,200 a

6 27,300 a a

8 56,400 a a

Flow Rate Supply Pressure= 15 psig(lbs./hr.) Return Pressure=0 psig

p/L, psi/100 ft.PipeSize(in.)

1⁄161⁄4 1

1⁄2 95 210 4503⁄4 210 450 950

1 400 860 1820

11⁄4 840 1800 3800

11⁄2 1270 2720 5700

2 2500 5320 a

21⁄2 4030 8520 a

3 7200 15,200 a

4 14,900 31,300 a

6 44,300 a a

8 91,700 a a

Flow Rate Supply Pressure= 5 psig(lbs./hr.) Return Pressure=0 psig

p/L, psi/100 ft.PipeSize(in.)

1⁄161⁄4 1

1⁄2 240 520 11003⁄4 510 1120 2400

1 1000 2150 4540

11⁄4 2100 4500 9500

11⁄2 3170 6780 14,200

2 6240 13,300 a

21⁄2 10,000 21,300 a

3 18,000 38,000 a

4 37,200 78,000 a

6 110,500 a a

8 228,600 a a

20

Condensate that collects ahead of a steamtrap is approximately at saturationtemperature and corresponds to theoperating pressure. As the condensate(normally above 212°F.) drains into thereturn line, it must flash to reach saturationtemperature at atmospheric pressure. Theexcess Btu’s are released in the form offlash steam in the return lines. The returnlines must be sized to handle the volume ofsteam and condensate at reasonablevelocities to minimize any backpressure.The volume of steam is normally severaltimes the volume of condensate and isgenerally maintained at less than 7,000 feetper minute.The following tables are for horizontal returnlines draining to a return system. Returnlines should pitch 11⁄2 in. per 10 ft. ofhorizontal run. Select the return line size

ASHRAEMethod forSizing ReturnLines

based on the steam operating pressure andthe allowable p/L, psi/100 ft. Selections for100 and 150 psig steam for either a ventedreturn system or a 15 psig pressurized returnsystem such as a flash tank, deaerator or closedreturn system.

Example: A condensate return system has asteam supply at 100 psig and the return line isat 0 psig and not vented. The return line ishorizontal and must have a capacity of 2500lbs./hr. What size pipe is required?

Solution: Since the system will be throttlingnon-subcooled condensate from 100 psig to 0psig there will be flash steam and the systemwill be a dry-closed return with horizontal pipe.Select a pressure drop of 1⁄4 psi/100 ft. anduse a 21⁄2 in. pipe for this system.

For these sizes and pressure losses, the velocity is above 7000 fpm.Select another combination of sizes and pressure loss.

Reprinted by permission of the American Society of Heating, Refrigeration and Air-ConditioningEngineers, Atlanta, Georgia, from the 1989 ASHRAE Handbook-Fundamentals

a

FLOW RATE (lbs./hr.) FOR DRY RETURN LINES

Flow Rate Supply Pressure= 50 psig(lbs./hr.) Return Pressure=0 psig

p/L, psi/100 ft.PipeSize(in.)

1⁄161⁄4 1

1⁄2 42 92 2003⁄4 91 200 420

1 180 380 800

11⁄4 370 800 1680

11⁄2 560 1200 2520

2 1110 2350 a

21⁄2 1780 3780 a

3 3190 6730 a

4 6660 13,800 a

6 19,600 a a

8 40,500 a a

21

Improper Regulator SizingOversized regulators will increasetemperature overshoots and cause theregulator to hunt. The result producestemperature variations from set point. Theregulator should be sized to handle themaximum system load without addingsafety factors.

Sensing Bulb LocationThe regulator sensing bulb must be fullyinserted in the fluid being controlled. Ontanks, use a bushing to reduce the tankconnection to match the bulb. Avoid nipplesand couplings. For piping, install in straightrun of tee with bushing. Flow should bethrough the side outlet of the tee. Locate asclose to heat exchanger outlet as possible.

Trap InstallationThe steam trap should be installed at least15 inches below the equipment beingdrained and should drain by gravity into avented condensate return unit. Lifting ofcondensate to overhead returns must beavoided at all cost. Any lifts will allowcondensate to return to the steam spaceduring light load or start up. Condensatebacking up into the steam space will causewater hammer and damage heatexchangers, regulators and traps.

Trap SizingAn undersized steam trap will causecondensate to back up into the heatexchanger. When this happens, theregulator must open wider and increase thepressure so that the trap can drain thecondensate. If a sudden load changeoccurs, this can cause a temperatureovershoot. Steam traps used withmodulating temperature regulators shouldbe sized to handle the maximumcondensate load at 1/2 psi differentialpressure. The trap must be 15 inchesbelow the condensate outlet and drain bygravity to a vented condensate unit. Trapsinstalled 7 inches below the condensateoutlet should be sized at 1/4 psidifferential.

Drip TrapsTo drain any condensate in the steam line,install drip traps in the steam line upstreamof the regulator. Condensate in the steamline can cause water hammer and damageto the regulator. On pilot operated valves,condensate can cause the regulator torespond slowly because condensate mustdrain through small orifices.

Pipe SizingThe steam pipe and return line should besized properly for the system load. Seecharts in this manual for pipe sizing.

SystemProblems thatCause PoorTemperatureControl

Chapter 4

TYPE OF HEATER APPLICATION TYPE OF REGULATOR

Instantaneous Heater Domestic Hot Water Series 2000 with pneumatic pilot for ± 4 deg. F.(must be used with anti-scald protection)

Process fluids Series 2000 with pneumatic pilot for ± 4 deg. F.Series 2000 with STPA pilot for ±10 deg. F. (System recirculation is recommended)

Wash down stations Same as process fluids (Pneumatic recommended if available)

Steam to water converters Series 1140 or Series 2000 with either direct or pneumaticoperated pilots. ± 10 deg. F. accuracy.

Semi-instantaneous Heater Domestic hot water Series 2000 with pneumatic temperature pilot ± 4 deg. F. accuracy (must be used with anti-scald protection)

Storage Heater Process fluids Series 2000 with pneumatic temperature pilot ± 4 deg. F. accuracyDirect-operated pilots ± 10 deg. F. accuracy.

Wash down stations Same as process fluids

22

Storage HeatersStorage heaters have a large tank and asteam coil in the tank, or a separate shelland tube heat exchanger with a circulatingpump. A temperature regulator senses thetank temperature. Cold water is addeddirectly into the storage tank. The tankusually has 10 to 20 minutes’ reservecapacity, and temperature change occursgradually. Systems with storage tanks mayhave a recirculating pump to providecontinuous recirculation of system water.

Semi-Instantaneous HeatersSemi-instantaneous heaters have a smalltank and either a steam coil in the tank, ora separate shell and tube heat exchangerand a circulating pump. The buffer tankshould have a minimum of one gallon ofstorage for every GPM of system draw rate.Larger tanks may be used where systemstorage is desired. Temperature changescan occur quickly. If system load changes,pneumatic regulators are recommended.

Typical Guidelines for Selection ofTemperature RegulatorsThe degree of temperature variationdepends on load change. The chart belowis based on 0% through 100% load change.

Semi-instantaneous systems may haverecirculating pumps to provide continuousrecirculation of system water. A minimumrecirculation of 20% of design flow rate isrecommended.

Instantaneous HeatersInstantaneous heaters do not have astorage tank. Water is heated directly in aheat exchanger and sent to the system. Ashot water is drawn off in the system, it isreplaced directly in the heat exchanger withcold water. This causes suddentemperature changes. Pneumatic regulatorsshould be used where possible, as theyhave faster response time. Wheninstantaneous heaters are used fordomestic hot water, separate anti-scaldprotection should be provided.Instantaneous heaters should haverecirculating pumps. The recirculating returnline should be at least 50 feet long, andthe pump should recirculate at least 20% ofthe system draw rate.

Classificationof Hot WaterHeaters

ControlSelectionGuidelines

23

Control of hot water temperature in astorage tank with a steam coil in the tank.

System Operation:The sensing bulb on the temperatureregulator senses the storage tanktemperature. On a drop in temperature, theregulator opens. On an increase intemperature, the regulator closes.

For domestic hot water service doubleseated valves should be avoided. Doubleseated valves do not close tight and maycause overheating during periods of nodemand.

Benefits:A self-contained regulator is inexpensive,simple to use and easy to adjust. Thestorage tank provides hot water during peakloads and prevents a wide temperaturefluctuation. Temperature changes occurgradually as hot water is drawn for thesystem and is a recommended practice fordomestic hot water service.

The 1140 Temperature Regulator isnormally open, thus it provides a minimalpressure drop making it ideal for steampressures less than 5 psig. It has a 40degree F. adjustable range.

PipingDiagrams

Application - Control of Temperature with Regulator

THERMOSTATICBULB

STORAGE HEATER

F & TTRAP

15" min.

VACUUM BREAKER

TO GRAVITY RETURN

STEAMSUPPLY

TEMPERATUREREGULATOR

F & TTRAP

24

Steam to domestic hot water storage tanksystem featuring a main valve with springand temperature pilots andstorage tankheater.

System Operation:The spring pilot is set to maintain amaximum steam pressure leaving the regu-lator to match the specification of the coils.

Variations in temperature of stored waterwill be sensed by the thermostatic bulb,and the temperature pilot will modulate themain valve to maintain the set temperature.

Benefits:• Pilot operation assures quick, accurate

response to load changes.

• Thermostatic bulb in storage tank guards against over temperature.

• Pressure reduction and temperature control are accomplished by a single main valve and pilot combination.

• Controlling maximum pressure in the steam coil limits the condensate temperature from the steam trap to reduce flash steam loss.

• A solenoid pilot and aquastat may be added as a safety control. The aquastat is normally set 5°F. higherthan the normal tank set temperature.

TEMPERATURE PILOT SPRING PILOT CONTROL

LINE

MAIN VALVE

STEAMINLET

THERMOSTATICBULB

STORAGE HEATER

F & TTRAP

15" min.

VACUUM BREAKER

TO GRAVITY RETURN

"Y"STRAINER

"Y"STRAINER

Application - Control of Temperature with Main Valve andSpring and Temperature Pilots

25

Benefits:• Main valve provides dead end service.• Main valve can be installed in header

servicing other low pressure devices.• Low pressure operation minimizes

steam temperature and reduces possibility of temperature overshoots.

• Low pressure operation reduces condensate temperature and reducesflash steam losses.

Pressure regulating valve and low pressuretemperature regulator with a main valve andspring pilot.

Spring pilot is set to maintain pressuresetting for a low pressure temperatureregulator.

System Operation:Main valve maintains tight shut-off untiltemperature regulator calls for steam toraise storage tank temperature.

MAIN VALVE

SPRING PILOT

RELIEF VALVE

CONTROL LINE

THERMOSTATICBULB

TEMPERATUREREGULATOR

TOSTEAMTRAP

STEAM INLET

STORAGE HEATER

F & TTRAP

15" min.

VACUUM BREAKER

TO GRAVITY RETURN

"Y"STRAINER

"Y"STRAINER

Application - Control of Temperature with Main Valve andSpring Pilot

26

Steam to hot water converter for hydronicheating system featuring a self-containedtemperature regulator such as HoffmanSeries 1140. Recommended for lowpressure applications.

With a system recirculating pump thesystem acts as a buffer to reduce suddentemperature changes.

System Operation:Fluid pumped through heat exchanger tubeis heated by controlling steam in shell ofheat exchanger.

Recirculating pump should be sized torecirculate a minimum of 20% of systemdesign load. Heated return water blendswith cold water make-up to reducetemperature fluctuations.

Benefit:Hot water can be generated without storagetanks for non-critical temperatureapplications such as steam to hot waterconverters for hydronic heating systems.

Note:Instantaneous heat exchange applicationsnot having a storage tank should beavoided where close temperature rangesare required, this is particularly true wheredemand loads may charge quickly.Pneumatic temperature regulators providethe fastest response. Critical applicationsshould use storage tanks equipped withsingle seated valves.

F & TTRAP

SHELL & TUBE HEAT EXCHANGER

F & TTRAP

CHECKVALVE

VACUUMBREAKER

“Y”STRAINER

“Y”STRAINER

“Y”STRAINER RECIRCULATION

FROM SYSTEM

STEAMSUPPLY

TEMPERATUREREGULATOR

HOT WATEROUT

TO GRAVITYRETURN

COLDWATERINLET

15" MIN.

Application - Shell and Tube Heat Exchanger,Instantaneous Type

27

Steam to hot water converter for hydronicheating system with main valve and springand temperature pilots. Recommended forhigh pressure steam applications.

System Operation:Spring pilot controls steam pressure toconverter on start-up. As thermostatic bulbsenses a temperature rise, temperaturepilot signals main valve to modulate andmaintain a constant temperature at theconverter outlet.

Benefits:• Eliminates need for separate

pressure reducing valves and temperature regulator.

• Self-contained system. No external power source required.

• For economical operation, main valve modulates to maintain set temperature at converter.

• Solenoid pilot can be added for shut off. Solenoid pilots may operate in response to aquastats, flow switches, timers, etc.

• Spring pilot may be set to limit maximum steam pressure in the shell.Limiting this pressure also limits the condensate temperature leaving the steam trap and increases system efficiency.

• Economical and reliable conversion method for better control of heating.

TEMPERATURE PILOT SPRING PILOT

CONTROL LINE

THERMOMETER

THERMOSTATIC BULB

WATER RETURN

CIRCULATING PUMP

INSTANTANEOUS HOT WATER HEATER

MAIN VALVE

STEAM INLET

"Y" STRAINER

STEAM SUPPLY

F & T TRAP

"Y" STRAINER

F & TTRAP

15" min.

TO GRAVITY RETURN"Y" STRAINER

Application - Conversion of Steam to a HydronicHeating System

28

Instantaneous heater recirculation systemwith main valve and pneumatic temperatureand air pilots.

System Operation:Pneumatic temperature pilot quickly senseschanges in temperature in a recirculatingsystem and signals the air pilot tomodulate the main valve to maintainsystem temperature.

Benefits:• Fast-acting temperature control for

rapidly changing loads.• Provides operator advantage of

shutting system down simply by stopping inlet air signal to air pilot.

• Pneumatic temperature pilots can be remotely located, long distances from the main valve.

• Wide, adjustable temperature range.

Note: Maximum outlet steam pressure will be 9psi less than air supply from the pneumatictemperature pilot. With a maximum 30 psiair supply, the maximum steam pressurewill be 21 psig using Hoffman AP-1A airpilot. Using a Hoffman AP-4A air pilot, outletpressures may be as high as 84 psig.Using an air PRV to limit the air pressurefrom the pilot will also limit the maximumsteam pressure in the heat exchangershell. Limiting steam pressure also limitsthe condensate temperature from the trapand improves system efficiency by reducingflash steam loss.

HEATEDWATERRETURN

CIRCULATING PUMP

MAIN VALVE

CHECKVALVE

HEATEDWATER

AIRSUPPLY

LINE

CONTROL LINE

PNEUMATICTEMPERATUREPILOT 315 PNT

STEAMINLET

COLD WATERAIRFILTER

REGULATOR

AIRPILOTAP -1A

INSTANTANEOUSHEATER

MAX. AIR PRESSURETO TEMP. PILOT IS36 PSIG.

F & TTRAP

15" min.

TO GRAVITY RETURN

"Y"STRAINER

"Y"STRAINER

Application - Pneumatic Temperature Pilot forInstantaneous Heater Recirculation System

29

Instantaneous heater recirculation systemwith two main valves and pneumatictemperature and air pilots. Controlled fromsingle set point.

System Operation:A pneumatic temperature pilot quicklysenses a change in temperature andincreases outlet signal pressure. From anapproximately 5 psi signal, no. 1 main valvebegins to open. As temperature continuesto drop, the outlet pneumatic signalpressure continues to increase. Atapproximately 9 psig signal, air pilot beginsto open which, in turn, begins to open mainvalve no. 2.

Benefits:• Fast acting temperature response

using pneumatic signal.• During light loads only main valve

no. 1 operates, during heavy loads both valves operate. This reduces possibility of wire draw on valve seats and reduces temperature swings as flow rates change.

• Wide adjustable temperature range.

Notes:1. Maximum outlet steam pressure using

this system will be 9 psi less than airsupply pressure from, for example,Hoffman 315 PNT. With maximum 30 psisupply from 315 PNT, maximum outletsteam pressure will be 21 psig.

2. Consult factory for proper sizing of valveswhen direct loading air from pneumatictemperature pilots.

HEATEDWATERRETURN

CIRCULATING PUMP

MAIN VALVE 2

CHECKVALVE

HEATEDWATER

AIRSUPPLY

LINE

CONTROL LINE

PNEUMATICTEMPERATURE

PILOT

STEAMINLET

COLD WATERAIRFILTER

REGULATOR

AIRSIGNAL

LINE

AIRPILOTAP -1A

INSTANTANEOUSHEATER

F & TTRAP

15" min.

TO GRAVITY RETURN

MAX. AIR PRESSURETO TEMP. PILOT IS36 PSIG.

CONDENSATE

MAIN VALVE 1

STEAM SUPPLY

"Y"STRAINER

"Y"STRAINER

"Y"STRAINER

F & TTRAP

"Y"STRAINER

Application - Pneumatic Temperature Pilot Maintains Temperature inInstantaneous Heater Recirculation System with Varying Load Conditions

30

Hot water storage tank using an externalshell and tube heat exchanger to heatwater in storage tank. A circulating pumpcirculates water from the tank through heatexchanger.

System Operation:Buffer storage tank provides reserve hotwater for peak loads and prevents widetemperature fluctuations.

Standard shell and tube heat exchangerscan be provided to replace obsolete tubebundles on old systems.

Temperature is controlled in storage tank.Due to large storage, temperature changesoccur gradually, allowing regulator time toreact and maintain tight temperaturecontrol.

System recirculating pump maintains hotwater availability to remote points in thesystem.

Benefits:Existing storage tanks with more than fiveminutes’ storage capacity can be upgradedby replacing tube bundle with shell andtube heat exchanger. Hot water capacity ofexisting tanks can be increased throughproper selection of new heat exchanger.

F & TTRAP

SHELL & TUBE HEAT EXCHANGER

F & TDRIPTRAPVACUUM

BREAKER“Y”

STRAINER

“Y”STRAINER

“Y”STRAINER

STEAMSUPPLYTEMPERATURE

REGULATOR

TO CONDENSATERETURN UNITBY GRAVITY

15" MIN.

RECIRCULATIONFROM SYSTEM

CIRCULATION PUMP

COLD WATER SUPPLY

BACKFLOW VALVE(IF REQUIRED)

HOT WATERBUFFER

STORAGE TANK

HOT WATEROUT

THERMOMETER

THERMOSTATICBULB

Application - Shell & Tube Heat Exchanger withLarge Storage Tank Heater

31

Shell and tube instantaneous heatexchangers can be used to provideconstant temperature in a system withoutlarge storage tanks.

System Operation:Small buffer storage tank blends hot andcold water to smooth load transitions andprevent wide temperature fluctuation.

Small buffer tank is used to blend make upwater and system returns flowing into ashell and tube heat exchanger. Constantsystem recirculation is required to preventtemperature fluctuations. The recirculatingpump should be sized for a minimum of20% of system draw rate.

Benefit:Standard heat exchangers save additionalcost and space requirements of largestorage tanks.

Small buffer tank systems with one to fiveminute reserves help smooth out loadtransitions caused by changes in flowrates. Instantaneous heat exchangerswithout buffer tanks usually causemomentary temperature fluctuations asflow rates or loads change.

Application - Shell & Tube Heat Exchanger withSmall Buffer Tank

F & TTRAP

SHELL & TUBE HEAT EXCHANGER

F & TTRAPVACUUM

BREAKER “Y”STRAINER

“Y”STRAINER

“Y”STRAINER

STEAMSUPPLYTEMPERATURE

REGULATOR

TO CONDENSATERETURN UNITBY GRAVITY

15" MIN.

RECIRCULATIONFROM SYSTEM

CIRCULATION PUMP

COLD WATER SUPPLY

BACKFLOW VALVE(IF REQUIRED)

HOT WATERBUFFER

STORAGE TANK

HOT WATERTO SYSTEM

32

System regulation with main valve,combination solenoid/temperature pilot,spring pilot and aquastat for safetyoverride.

System Operation:The main valve with a combination of spring,temperature and solenoid pilots controlsthe supply pressure to the heat exchangerand the temperature of liquid flowingthrough the heat exchanger. If thetemperature rises a few degrees above theset point on the temperature pilot, theaquastat shuts down steam flow to theheat exchanger.

A main valve such as Hoffman Series 2000is sized to handle maximum conditions ofthe system. This application uses anormally closed solenoid pilot wired to aflow switch, aquastat, and remote switch.The aquastat is set 5 - 10˚F. above thecontrol temperature. When the remoteswitch is turned on and the temperature ofthe liquid is below the aquastat set pointtemperature and liquid is flowing across theflow switch, the solenoid pilot is energized.

If any of the three conditions mentioned arenot met, the system will shut down. Thisfully automatic type system should be usedwhere temperature limits on processes arecritical. This application can also be used asa safety override for other systems such asdomestic hot water.

Benefits:• Temperature/pressure regulation is

maintained with just one valve.• Temperature safety override is built in.• No flow safety override.• May be wired into recirculating pump

contactor to shut off steam flow in the event of power loss or if pump is shut off.

COLD WATER

STEAMTRAP PUMP

WATER CIRCUIT WITHRECIRCULATING LOOP

FLOW SWITCH

MAINVALVE

COMBINATIONSOLENOID PILOTTEMPERATURE PILOTSPRING PILOT

PRESSUREFEEDBACK

VACUUMBREAKER

REMOTE SWITCHING

POWER SUPPLY

15" MIN.

STEAMSUPPLY

AQUASTAT

“Y”STRAINER

THERMOSTATICBULB

"Y"STRAINER

Application - Temperature Control with Main Valve, CombinationSolenoid/Temperature Pilot, Spring Pilot and Aquastat

33

Domestic hot water system designed tohandle peak loads and low demandperiods. Uses two main valves in parallelwith temperature and solenoid pilots.

This system configuration provides reducedsteam capacity during low periods and alsogives high temperature limit control.

System Operation:Two regulators with temperature/solenoidpilot combinations are sized for maximum(heat exchanger) flow. One of the regulatorsis sized for "off peak" demand.Temperature setting for this regulator wouldbe set 5° F. above the second valve in thissystem. During peak demand, bothregulators supply steam to heat exchangerto heat water flowing through it. As demandfor water drops, temperature rise satisfiespilot of larger regulator and shuts it off.Then, only smaller valve supplies steam toheat "off peak" demand, thus savingenergy. Aquastat and solenoid valves are

provided as a safety override shouldtemperature rise beyond set point oftemperature pilots. An optional flow switchmay be used to shut steam off during noflow. Two Hoffman Series 2000 mainvalves are shown here.

Benefits:• Automatic control of water

temperatures.• Stable temperature control for

off peak demand.• Safety override provided for

temperature control.• Fast-acting temperature control

to handle rapidly changing loads.

TEMPERATURE PILOT

MAIN VALVE

SOLENOIDPILOT

MAIN VALVE

SOLENOIDPILOT

HEATEXCHANGER

TOPOWERSOURCE

MIXING TANK

AQUASTAT

WATERSYSTEM

DRIPTRAP

STEAMSUPPLY

TEMPERATURE PILOT

COLD WATER

F & TTRAP

CIRCULATING PUMP

NORMALLY CLOSED BYPASS VALVE

FLOW SWITCH

(OPTIONAL)

15" MIN.

Application - Temperature Control with Two Main Valvesand Temperature Pilots

34

Shell and tube heat exchanger using a 2-way valve to control hot water temperatureplus a 3-way valve to provide hot and coldmix for safety override.

System Operation:Water is heated in heat exchanger toapproximately 10 deg. F. above designtemperature. A 3-way mixing valve thenmixes hot and cold water to designtemperature.

Benefit:In the event of a temperature regulatorfailure, the outlet temperature is limited.This should be used in conjunction with alarms to indicate failure of either regulator.

Application - Instantaneous Heater using 3-way MixingValve for Stand-by Protection

SHELL & TUBE HEAT EXCHANGER

F & TTRAP VACUUM

BREAKER“Y”

STRAINER

“Y”STRAINER

RECIRCULATIONLINE

STEAMSUPPLY

HOT WATERSET AT

SYSTEM TEMP.

COLDWATERSUPPLY

TEMPERATUREREGULATOR

3-WAYTEMPERATURE

REGULATOR

COLDWATER

F & TTRAP

“Y”STRAINER

15" MIN.

THERMOSTATICBULB

THERMOSTATICBULB

HOTWATER

CONDENSATERETURN TO

CONDENSATE UNIT

35

Heating coil in boiler provides hot water.Three-way valve mixes hot water with coldwater to regulate temperature.

System Operation:Temperature regulator is set to maintainrequired hot water temperature. Circulatorpump running continuously provides flowacross the sensing bulb to operate theregulator.

Benefit:Heating boiler may be used to generate hot water.

Application - Control of Domestic Hot Water from Coil inHot Water or Steam Boiler to Reduce Temperature

CIRCULATING PUMP

CHECKVALVE

3-WAYTEMPERATURE

REGULATOR

COIL INBOILER

COLD BYPASS

HOT BYPASS

BOILER

RETURN CIRCULATION

COLD WATERSUPPLY

TO BUILDING

THERMOMETER

NORMALLYCLOSED

NORMALLYCLOSED

RECIRCULATED WATER AND COLD WATER

THERMOSTATICBULB

ALABAMA Mangham & Associates, Inc.

Birmingham—205/956-2362Fax: 205/956-2477

ALASKALarry Harrington Co., Inc.

Bellevue (Seattle) WA—206/455-0800Fax: 206/455-4640

ARIZONA J & B Sales Company

Phoenix—602/258-1545, Fax: 602/258-9719

ARKANSASJohnson & Scott, Inc.

Little Rock—501/370-5050Fax: 501/370-5051

Hydronic Technology, Inc.Shreveport, LA—318/797-1500Fax: 318/797-1509

Boone & Boone Sales Co., Inc.Tulsa, OK—918/664-9756, Fax: 918/664-1675

CALIFORNIA California Hvdronics Corp.

Hayward (San Francisco)—510/293-1993Fax: 510/293-3080Roseville (Sacramento)—916/773-1908Fax: 916/773-1910

Dawson CompanyAltadena (Los Angeles)—626/797-9710Fax: 626/798-4659San Diego—619/541-7867, Fax: 619/541-0333

COLORADO McNevin Company

Denver—303/322-0165, Fax: 303/322-0374

CONNECTICUT The Bernard M. Packtor Company

Hamden (New Haven) 203/288-5241Fax: 203-287-1798

DELAWARE R. D. Bitzer Co., Inc.

Philadelphia, PA—215/635-2818Fax: 215/635-0615

Cummins-Wagner Co., Inc.Annapolis Junction, MD—800/966-1277Fax: 301/490-7156

FLORIDA George A. Israel Jr., Inc.

Jacksonville—904/355-7867Fax: 904/355-0077Miami—305/592-5343, Fax: 305/591-4356Orlando—407/423-5078, Fax: 407/423-0918Tallahassee—850/656-2055Fax: 850/656-1475Tampa—813/839-2161, Fax: 813/832-3182

Mangham & Associates, Inc.Birmingham, AL—205/956-2362Fax: 205/956-2477

GEORGIA Clary & Associates, Inc.

Atlanta—404/873-1861, Fax: 404/873-1867George A. Israel Jr., Inc.

Jacksonville, FL—904/355-7867Fax: 904/355-0077Tallahassee, FL—850/656-2055Fax: 850/656-1475

HAWAII Dawson Company

Altadena (Los Angeles), CA—626/797-9710Fax: 626/798-4659

IDAHO Gritton & Associates, Inc.

Salt Lake City, UT—801/486-0767Fax: 801/485-6364

Larry Harrington Company, Inc.Portland, OR—503/228-4324Fax: 503/228-0219

ILLINOIS Bornquist, Inc.

Chicago—773/774-2800, Fax: 773/763-6534Blackmore & Glunt, Inc.

Maryland Heights (St. Louis) MO—314/878-4313, Fax: 314/878-6029

John A. Sandberg Co., Inc.East Moline—309/796-2371Fax: 309/796-2330

Hydronic & Steam Equipment Co., Inc.Indianapolis, IN—800/669-4926Fax: 317/577-7109

INDIANA Hydronic & Steam Equipment Co., Inc.

Evansville—800/473-2753, Fax: 812/479-7650Ft. Wayne—219/489-5785, Fax: 219/489-4369Indianapolis—800/669-4926Fax: 317/577-7109South Bend—800/932-6490Fax: 219/234-6611

Bornquist, Inc.Griffith—773/774-2800, Fax: 773/763-6534

Blackmore & Glunt, Inc.Cincinnati, OH—513/489-5225Fax: 513/489-8755

IOWA Products, Inc.

Des Moines—515/288-5738Fax: 515/288-2574

John A. Sandberg Co., Inc.East Moline, IL—309/796-2371Fax: 309/796-2330

Verne Simmonds CompanyOmaha, NE—402/592-3131Fax: 402/592-0853

KANSAS Blackmore & Glunt, Inc.

Lenexa (Kansas City)—913/469-5715Fax: 913/469-1085

KENTUCKY Blackmore & Glunt, Inc.

Cincinnati, OH—513/489-5225Fax: 513/489-8755

Hydronic & Steam Equipment Co., Inc.Evansville, IN—800/473-2753Fax: 812/479-7650

Johnson & ScottNashville, TN—615/254-5454Fax: 615/242-9243

LOUISIANA Hydronic Technology, Inc.

New Orleans—504/827-1163Fax: 504/827-1167Shreveport—318/797-1500Fax: 318/797-1509

Oslin Nation CompanyMinden—318/222-2700Fax: 318/371-0020

MAINE F.l.A., Inc.

Woburn (Boston) MA—617/938-8900Fax: 617/933-3965

MARYLAND Cummins-Wagner Co., Inc.

Annapolis Junction—800/966-1277Fax: 301/490-7156

Thermoflo Equipment Co., Inc.Pittsburgh, PA—412/366-2012Fax: 412/367-0842

MASSACHUSETTS F.l.A., Inc.

Woburn (Boston)—781/938-8900781/933-3965

The Bernard M. Packtor CompanyHamden (New Haven) CT—203/288-5241, Fax: 203/287-1798Albany, NY—518/459-1060Fax: 518/458-8776

MICHIGANR. L. Deppmann Company

Southfield (Detroit)—248/354-3710Fax: 248/354-3763Grand Rapids—616/656-0821Fax: 616/656-0830Saginaw—517/777-2960, Fax: 517/777-5061

Hydro-Flo Products, Inc.Brookfield (Milwaukee) Wl—414/781-2810, Fax: 414/781-2228

MINNESOTA Bernard J. Mulcahy Company, Inc.

Bloomington—612/854-3621Fax: 612/854-7586

MISSISSIPPI Hydronic Technology, Inc.

New Orleans, LA—504/827-1163Fax: 504/827-1167

Johnson & ScottLittle Rock, AR—501/370-5050Fax: 501/370-5051

MISSOURI Blackmore & Glunt, Inc.

Lenexa (Kansas City) KS—913/469-5715Fax: 913/469-1085Maryland Heights (St. Louis)—314/878-4313, Fax: 314/878-6029

Johnson & ScottMemphis, TN—901/388-2919Fax: 901/388-0989

MONTANA Larry Harrington Company, Inc.

Spokane, WA—509/325-1654Fax: 509/325-6838

NEBRASKAVerne Simmonds Company

Omaha—402/592-3131, Fax: 402/592-0853

NEVADA California Hydronics Corp.

Sacramento, CA—916/773-1908Fax: 916/773-1910

Dawson CompanyLas Vegas, NV—702/735-1226Fax: 702/7351232

Gritton & Associates, Inc.Salt Lake City, UT—801/486-0767Fax: 801/485-6364

NEW HAMPSHIRE F.l.A., Inc.

Woburn (Boston) MA—617/938-8900Fax: 617/933-3965

NEW JERSEY Wallace-Eannace Assoc., Inc.

Franklin Lakes—201/891-9550Fax: 201/891-4298

R. D. Bitzer Co., Inc.Philadelphia, PA—215/635-2818Fax: 215/635-0615

NEW MEXICO Boyd Engineering Company, Inc.

Albuquerque—505/275-1250Fax: 505/275-1193

NEW YORK Wallace-Eannace Assoc., Inc.

Plainview—516/454-9300, Fax: 516/454-9307Frank P. Langley Company, Inc.

Johnson City—607/766-9950,Fax: 607/766-9948Rochester—716/248-5010, Fax: 716/381-0512Amherst (Buffalo)—716/691-7575Fax: 716/691-7347

The Bernard M. Packtor CompanyAlbany—518/459-1060, Fax: 518/458-8776

Syracuse Thermal Products, Inc.East Syracuse—315/437-7321Fax: 315/437-7429

NORTH CAROLINA James M. Pleasants Company, Inc.

Greensboro—800/365-9010Fax: 910/378-2588

NORTH DAKOTA Bernard J. Mulcahy Co., Inc.

Bloomington, MN—612/854-3621Fax: 612/854-7586

OHIO Blackmore & Glunt, Inc.

Cincinnati—513/489-5225, Fax: 513/489-8755Omni-Flow, Inc.

Macedonia (Cleveland)—330/468-1102Fax: 330/468-1113

Steffens-Shultz, Inc.Columbus—614/274-5515, Fax: 614/274-0126Dayton—937/278-7903, Fax: 937/278-7825

Thermoflo Equipment Co., Inc.Pittsburgh, PA—412/366-2012Fax: 412/367-0842

OKLAHOMA Boone & Boone Sales Co., Inc.

Oklahoma City—405/525-7475Fax: 405/521-1448Tulsa—918/664-9756, Fax: 918/664-1675

OREGON Larry Harrington Company, Inc.

Portland—503/228-4324, Fax: 503/228-0219

PENNSYLVANIA R. D. Bitzer Co., Inc.

Philadelphia—215/635-2818Fax: 215/635-0615

Thermoflo Equipment Co., Inc.Pittsburgh—412/366-2012, Fax: 412/367-0842

Frank P. Langley Co., Inc.Amherst (Buffalo) NY—716/691-7575Fax: 716/691-7347

RHODE ISLAND F.l.A, Inc.

Woburn (Boston) MA—617/938-8900Fax: 617/933-3965

SOUTH CAROLINA James M. Pleasants Co., Inc.

Greensboro, NC—800/365-9010Fax: 910/378-2588

SOUTH DAKOTABernard J. Mulcahy Co., Inc.

Bloomington, MN—612/854-3621Fax: 612/854-7586

Verne Simmonds Co.Omaha, NE—402/592-3131Fax: 402/592-0853

TENNESSEEJohnson & Scott

Nashville—615/254-5454, Fax: 615/242-9243Memphis—901/388-2919, Fax: 901/388-0989

Clary & Associates, Inc.Atlanta, GA—404/873-1861Fax: 404/873-1867

James M. Pleasants Co., Inc.Greensboro, NC—800/365-9010Fax: 910/378-2588

TEXASBoyd Engineering Company, Inc.

Albuquerque, NM—505/275-1250Fax: 505/275-1193

Oslin Nation CompanyAustin—512/306-1672, Fax: 512/306-1673Ft. Worth—817/590-2500, Fax: 817/590-2508Dallas—214/631-5650, Fax: 972/988-1446Houston—281/240-6950, Fax: 281/240-6957San Antonio—210/342-5544Fax: 210/342-2818

Therm/Mech SalesLubbock—806/763-5411, Fax: 806/763-7036

UTAH Gritton & Associates, Inc.

Salt Lake City—801/486-0767Fax: 801/485-6364

VERMONT F.l.A., Inc.

Woburn (Boston) MA—617/938-8900, Fax: 617/933-3965

The Bernard M. Packtor Co.Albany, NY—518/459-1060Fax: 518/458-8776

VIRGINIA TLA, Inc.

Richmond—804/321-4444Fax: 804/321-3112Virginia Beach—757/497-3567Fax: 757/490-7362

Cummins-Wagner Co., Inc.Annapolis Junction, MD—800/966-1277, Fax: 301/490-7156

WASHINGTON Larry Harrington Company, Inc.

Seattle—206/455-0800, Fax: 206/455-4640Spokane—509/325-1654, Fax: 509/325-6838

WASHINGTON, DC Cummins-Wagner Co., Inc.

Annapolis Junction, MD—800/966-1277, Fax: 301/490-7156

WEST VIRGINIABlackmore & Glunt, Inc.

Cincinnati, OH—513/489-5225Fax: 513/489-8755

TLA, Inc. Richmond, VA—804/321-4444Fax: 804/321-3112

Thermoflo Equipment Co., Inc.Pittsburgh, PA—412/366-2012Fax: 412/367-0842

WISCONSINHydro-Flo Products, Inc.

Brookfield (Milwaukee)—414/781-2810, Fax: 414/781-2228

Bernard J. Mulcahy Co., Inc.Bloomington, MN—612/854-3621Fax: 612/854-7586

WYOMING Gritton & Associates, Inc.

Salt Lake City, UT—801/486-0767Fax: 801/485-6364

McNevin CompanyDenver, CO—303/322-0165Fax: 303/322-0374

CANADA: ITT Fluid Products Canada55 Royal Road, Guelph, Ontario, N1H1T1Phone: 519/821-1900, Fax: 519/821-2569

FOR MORE DETAILS CALL YOUR LOCAL HOFFMAN REPRESENTATIVE

3500 N. Spaulding AvenueChicago, Illinois 60618tel: 773 267-1600fax: 773 267-0991www.hoffmanspecialty.com

©1999 ITT IndustriesPrinted in U.S.A. 1-99 HS-501(A)