Bi-Metal Thermometers

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DiaITemp

™

Features

Excellence in a product never occurs by mere chance. It is 

the result of constant striving for perfection in the little things

as well as the big. That is why OMEGA’s Stainless

Steel Dial Thermometers are used by industries,

laboratories, processors, universities and

governments all over the world. Easy-to-

read dials, rugged construc tion, leakproof

heliarc welds and guaranteed accuracy

assure the discriminating buyer 

of the finest thermometer which,

incidentally, is easily within reach 

of even the most modest budget.

Available in a wide variety of dial

sizes, stem lengths, temperature

ranges and mounting connections,

OMEGA

®

thermometers offer the 

user great flexibility in selecting 

just the right configuration to meet

virtually every temperature

measuring requirement. These

accurate thermometers have been

manufactured to the very highest

standards of excellence by expert

craftsmen using the finest materials

available. An OMEGA stainless steel

thermometer is a lasting investment value in

scientific temperature measurement. 

Precision Built for Lifetime Service

Critical assembly points in DiaITemp™ thermometers are

heliarc welded. No brazing metal is added. Stainless steel

stem, plugs and mounting nuts are actually fused together to

form a perfect moisture-proof bond. There’s no possibility of

rust or corrosion setting in! Very highly corrosion-resistant

type 304 stainless steel is used for all stems in every

DiaITemp™ thermometer listed in this handbook. Each

thermometer is meticulously manufactured step by step to

produce a most efficient precision thermometer. Bi-metal coils

are wound to pre-determined standards and are individually

trimmed and tested, one by one, until they provide the exact

amount of rotation required for an accurate full scale reading.

OMEGA provides an instrument far above the average in

ruggedness, dependability and accuracy! 

Easy-to-Read

Clear, crisp, raised marks and numbers on the dial provide

exceptional readability with this “pointer to dial” method of

indication. Double anodized aluminum dials with satin matte

finish background and black raised marks and numbers

assure minimum parallax. 

Rugged and Reliable

The all metal construction, (except for the optically clear 

crystal) of DiaITemp thermometers and their heliarc welded

fabrication make them virtually unbreakable. The type 304

stainless steel stems offer exceptional protection against

highly corrosive materials. The bi-metal principle of

temperature measurement eliminates the need for gas, vapor,

mercury, alcohol, or capillary tubing. With no gears or linkage

to impede movement, the direct drive from helix coil to pointer

gives an accurate indi cation every time. There are no parts to

wear out or fail, no possibility of leakage or fluid column

separation and no glass tube breakage. 

Accurately Calibrated

The most precise calibrating methods are used in the

fabrication, calibrating and testing of each sensing helix 

coil before it goes into an OMEGA thermometer. Each

thermometer is then individually calibrated for maximum

accuracy. All calibration is performed to instrumentation which

has been cali brated to standards traceable to the Institute of

Science and Technology [NIST, formally the National Bureau

of Standards (NBS)]. Each thermometer must meet an

accuracy tolerance within 1% of the range over the full scale.

This high degree of perfection is achieved by using bi-metal

materials manufactured and fabricated under near-laboratory

conditions. Experienced craftsmen and engineers ensure

precise production of each unit in every phase of

manufacturing. As a final check, each instrument is

given a com plete heat test before it is packed,

eliminating any chance for error. DiaITemp

thermometers read right because they are

right! They’re also protected against

temperature over-range. Occasionally,

operating temperatures may

accidentally exceed the range of the

thermometer. This, however, will not

harm its accuracy. The precision 

bi-metal coils, which transform heat

into pointer motion, will withstand a

50% over-range on instruments up 

to and including 500°F. A 10% 

over-range is permissible on higher

temperature ranges. Under-ranging

within the 50% limit on all ranges will

also not harm its accuracy. 

Plus Advantages

DiaITemp metal thermometers have 

cer tain obvious advantages over

conventional glass units. For exam ple, they 

are virtually unbreakable. The dial and pointer

principle is far easier to read at a glance. Long stem

models can be immersed in deep vats or tanks where there 

is a variation between top and bottom temperatures. Stainless

steel is easy to clean. In addition, the DiaITemp thermometer

can be plunged directly into molten lead or babbit.

Temperature readings are stabilized within 40 seconds or

less. All in all, regardless of the application, these rugg ed

units reveal temperatures more easily, more quickly and with

greater depen dability. 

Applications and Usage. 

(partial list)

Air Conditioning, Asphalt, Boilers, Baking, Burners, Cabinets,

Chemicals, Cookers, Coolers, Coffee Urns, Canning,

Concrete, Dairies, Ducts, Dyeing Equipment, Developers,

Dehydrators, Engines, Extruders, Enclosures, Grain Elevators,

Furnaces, Fire Boxes, Food Processors, Greenhouses, Glue

Machines, Heaters, Heat Exchangers, Incinerators, Instrument

Panels, Impregnating Tanks, Incubators, Laboratories, Lumber

Mills, Manifold, Marine, Metallurgy, Milling, Mineralogy,

Platens, Processing, Plastics, Plating, Petroleum,

Petrochemical, Pharmaceuticals, Photography, Plumbing,

Pickling, Piping, Pulp, Pasteurizing, Quenching, Refrigeration,

Refineries, Solder, Stacks, Ships, Steam, Generators, Sewage

Works, Silos, Soil, Testing, Tanks, Tempering, Tire

Vulcanizing, Textiles, Throwing, Utilities, Vaporizers,

Ventilation, Water Works, and many others.

Bi-Metal Thermometers

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E-4

E

Dual scaled

models

available.

Measurements

shown in both

°C and °F.

Contact the

Sales

department 

to order.

Specifications

Materials:

Stems: All models, Type 304 stainless steel (highly

resistant to corrosion); standard lengths—2

1

⁄

2

", 4", 6", 9",

12", 15", 18", 24", 30", 36", optional: Intermediate, or to 80"

on the angle form (back connected) only; please note that a

4" stem is the shortest length for ranges 0 to 100°F, 25 to

125°F and 0 to 50°C; the 9" length is the most popular, 

and stocked for immediate delivery

Heads and Bezels:

All models, polished Type 302 stainless steel

Mounting Bushings and Nuts:

All models, Type 303 stainless steel

Crystals: Optically clear strong glass 

Optional: Unbreakable clear plastic, all models 

(not recommended for ranges over 300°F)

Dials: Anodized aluminum; raised black marks 

and numbers with satin matte finish background; 

easy to read; minimum parallax

Angle Form (Back Connected): Models Q, G, H, A, R, B, S,

QP, GL, HL, T, G/EMB and H/EMB

Straight Form (Bottom Connected): Models X, XR, V and

VR; an outstanding feature of the DialTemp

™

straight form

thermometer is the adjustable mounting nut which makes it

possible to turn the head a full 360° on the stem axis and then

lock it in the exact position desired for maximum visibility;

available with or without external reset

Accuracy: All Models are accurate to within plus or minus 

1% of the full scale; readings are stabilized within 40 seconds

Pointed Stems: Optional on all models; excellent for probing

asphalt, compost, soil, frozen foods or other semi-solid

materials

Mounting Connections: Standard on QP, GL and HL is a

reset bushing; standard on models Q, G, H, and T is a plain

bushing; standard on the models A, R, B, S, XR, and VR is

the 

1

⁄

2

NPT mounting thread; standard on the models G/EMB

and H/EMB are stainless steel “ears” at 3 and 9 o’clock with

0.144" diameter screw hole; optional threads are available;

see page E-15; allow extra time for any optional mounting

connections; consult factory for price and delivery

Maximum Temperature and Pressure Ratings:

Use of a thermowell is recommended for all pressure

applications; the maximum ambient temperature for the entire

assembly is 300°F; the ambient temperature with a plastic

lens is 200°F, this does not apply to the E-20 pocket

thermometers – they are not rated for pressure

Immersion: For correct temperature measurement, 

the stems of all models in all ranges must be immersed 

2" in water and 4" in gas except for the 0 to 100°F, 

25 to 125°F and 0 to 50°C ranges which require 

3

1

⁄

2

" in liquid and 5" in gas

Temperature Ranges:

Fahrenheit: 0 to 100°F, 25 to 125°F, -40 to 160°F, 

0 to 200°F, 0 to 250°F, -50 to 300°F, 50 to 300°F, 

50 to 400°F, 50 to 500°F, 250 to 600°F, 150 to 750°F, 

200 to 1000°F

Celsius: 0 to 50°C, -40 to 70°C, 0 to 100°C, -10 to 110°C, 

0 to 150°C, 0 to 200°C, 0 to 300°C, 100 to 500°C

Other ranges are available by special order with minimum

quantity requirement; please note: for ranges 0 to 100°F, 

25 to 125°F and 0 to 50°C, the shortest stem length 

is 4 inches; select most common ranges for 

“off-the-shelf” delivery

O.E.M. Applications: If you are an original equipment

manufacturer and plan to incorporate the DiaITemp

thermometer into your finished product for resale, 

special ranges or special dials can be made to suit your

particular requirements; such specials can bear your own

company name and/or trade mark on the dial, 

but a minimum quantity order must be placed; for 

full information, please write, giving desired range, dial size,

stem length, mounting connection, and your special

requirements; we will be happy to quote; any DiaITemp

thermometer will complement your equipment, because its

quality, appearance and performance is unsurpassed

External Reset: Models A and B are equipped with 

an external reset screw; a hex key to fit it is furnished with

each unit; this allows resetting the pointer without removing

the bezel or disassembling the unit

Immersion: For correct temperature measurement, the stem

of all models in all ranges must be immersed at least 2" in

liquids, and 4" in gas except for 0 to 100°F, 24° to 125°F, and

0 to 50°C, which require at least 3

1

⁄

2

" in liquid and 5" in gas;

the most common immersion length offered is 9"; these are

stocked for “off-the-shelf” delivery in popular ranges; prices

are given for popular-stock ranges; for other stem lengths,

consult Sales department for price and delivery

DIAL

POINTER

GLASS

GASKET

BEZEL

HEAD

RESET SCREW (OPTIONAL)

HELIARC STAINLESS STEEL WELDS

MOUNTING NUT

STEM

SHAFT

HELIX

PLUG

HELIX

STAINLESS

STEEL

WELDS

LENGTH FIGURED FROM BOTTOM OF HEX TO TIP OF STEM

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One Omega Drive | Stamford, CT 06907 |   1-888-TC-OMEGA (1-888-826-6342) |    [e-mail] 

www.omega.com

More than 100,000 Products Available!

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Temperature

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Instruments, Glass Bulb Thermometers, Handheld Instruments 

for Temperature Measurement, Ice Point References, 

Indicating Labels, Crayons, Cements and Lacquers, Infrared 

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and Assemblies,  Temperature & Process Meters, Timers and 

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