Bimetal Thermometers
Is a bimetal thermometer tip sensitive? Yes. For the most accurate temperature reading the stem must be immersed into the medium at least 2-3". Unique to all Tel-Tru bimetal thermometers is a groove on the stem that equals the minimum immersion depth so you won"t have to measure.
How do I recalibrate a bimetal thermometer? To recalibrate Tel-Tru Bimetal Thermometers see our Pocket/Laboratory/Testing/Spot Checking or Industrial Bimetal Thermometers product manuals.
How can I tell if my thermometer is reading accurately? The Tel-Tru Check-Set Calibrator allows you to verify the accuracy of dial thermometers and digital probes of all sizes. Our multi hole units fit probes up to .250", .125", .187" and .375" diameter. The Check-Set Calibrator allows accurate verification of thermometer accuracy at the temperature point critical to the users actual application. For more information visit Check-Set Calibrators.
What is the accuracy of Tel-Tru bimetal thermometers? +/- 1% full span per ASME B40.3 Grade A.
Are Tel-Tru bimetal thermometers hermetically sealed? Yes, Tel-Tru bimetal thermometers are hermetically sealed per ASME B40.3 test.
What is the shortest stem length available on Tel-Tru bimetal thermometers? Stem length depends on the model, temperature range and the application. Please contact us at 800-232-5335/585-232-1440 or contact us via the web.
Can I shorten the stem length of a bimetal thermometer by cutting it? No, you will destroy the thermometer. The bimetal coil assembly in the lower 2" of the stem is the operating mechanism.
How do you measure stem lengths? Stem lengths for thermometers with threaded connections are measured from the top of the thread to the tip of the stem. Non threaded thermometers are measured from the back of the case to the tip of the stem. See our Bimetal Thermometer catalog.
Can you make special dials? Custom dial configurations are available. Contact our factory with your requirements. Please contact us at 800-232-5335/585-232-1440 or contact us via the web.
What temperature ranges are available on Tel-Tru bimetal thermometers? See our Bimetal Thermometer catalog.
What material is used to make Tel-Tru thermometers? 304SS is the standard material for the case, bezel and wetted parts. 316 stainless steel parts are available on some models as an option.
Why do some Tel-Tru thermometers have a pointed stem? The pointed stem is the result of a high quality manufacturing process for sealing the stem tip.
What is the maximum stem pressure a bimetal thermometer can withstand? Bimetal thermometers are not certified for pressure applications. It is standard industry recommendation that anytime pressure is an issue a thermowell should be used for safety reasons.
What is the anti-parallax dial? The dial is not flat. There is an outer ring that is raised to the same height as the pointer which allows the pointer position to be read more accurately from various angles.
What are the operating temperature limits for Tel-Tru bimetal thermometers with silicone fill? The maximum operating temperature is 500F (260C). The minimum operating temperature is -50F (-45C).
How quickly can you manufacture bimetal thermometers? 1 to 2 day turnaround is available. Standard lead time is 5 to 7 business days. Please contact us at 800-232-5335/585-232-1440 or contact us via the web.
Do Tel-Tru bimetal thermometers carry the "N Stamp" so that they can be used on the "hot" system (nuclear side) of a nuclear power plant? Tel-Tru products do not carry the "N Stamp", but our products are used in the non-nuclear system or side of nuclear power plants. To our knowledge, there are no manufacturers of bimetal thermometers who have "N Stamp" approval.
Does Tel-Tru have a lens material for thermometers which is UV stabilized? Both the polycarbonate plastic and the acrylic plastic materials are UV stabalized materials, which means the yellowing is delayed but will still happen over a long period of time.
Can you offer a silicone filled bimetal thermometer with shatterproof glass? Yes, polycarbonate plastic is standard on silicone thermometers. Shatterproof glass is available upon request.
Can bimetal thermometers be filled with glycerine instead of silicone? No. Glycerine is not an option for filling bimetal thermometers because it is too viscous and it will not tolerate high temperatures.
Can you manufacture bimetal thermometers with non-standard stem lengths? Yes. Tel-Tru can manufacture custom stem lengths up to 120" for bimetal thermometers.
Are calibration certificates and certificate of origin and compliance available? Yes, contact factory for charges (if required) 800-232-5335/585-232-1440. These certificates must be requested on your purchase order with the thermometers or pressure gauges.
Gas Actuated Thermometers
What is the active length of a bulb on Tel-Tru Gas Actuated thermometers? The standard active length of a bulb is 3" x 3/8" diameter for all temperature ranges and capillary lengths up to 120 feet (36m). A 6" x 1/4" is available on request for certain temperature ranges.
Surface Thermometers
Can a Surface Thermometer be calibrated in the field? No. The surface thermometer is calibrated when it is originally manufactured to an accuracy of +/- 2%.
Barbecue Thermometers
Do you manufacture thermometers for barbecue cookers and smokers? Yes. Visit Barbecue Thermometers.
Check-Set Calibrators
Why should I register the unit? Registering your Check-Set:
  • Ensures warranty coverage for one year from date of manufacture.
  • Will allow you to receive technical support, warranty repair service, maintenance, and important product updates.
  • Allows you to receive valuable information on how to have your Check-Set recalibrated every year and extend your warranty.
  • Offers suggestions on how to keep your Check-Set running trouble free for years to come.
  • How do I register the unit? Upon receiving and unpacking your Check-Set, register the new unit by scanning the QR code on the front of the included Quick Start Guide, or at Warranty Registration, and filling out the online form.
    How do I order annual recertification?
  • Tel-Tru offers annual maintenance, inspection, cleaning, and accuracy recertification of each Check-Set thermometer calibrator.
  • Recertification automatically extends the product warranty one year, for up to nine years.
  • Visit us at Check-Set Calibrators or contact Tel-Tru Customer Service at 800-232-5335 for details.
  • What if the green light goes out? If the green light should remain out, or the red light comes on, the Check-Set calibrator may not be working properly. It is recommended that you stop use of the calibrator and contact Tel-Tru at 800.232.5335 or contact us via the web for instructions.
    What if the green ready light stops flashing or does not come on when expected? Double check power cord hasn"t come unplugged from the wall. After the heating or cooling period it could mean one of the following:
  • The unit is off calibration by more than ±1°F as indicated by the red light.
  • The green light bulb is broken.
  • If all else fails, call the factory to arrange for maintenance service.
  • What if my Check-Set unit needs cleaning? Only insert clean thermometers into the Tel-Tru Thermometer Calibrator opening.
    • Wipe the stem of the thermometer before inserting it into the calibrator.
    • Wipe the stem again before inserting the thermometer into any food product.

    If it becomes necessary to clean foreign matter from inside the opening in the Tel-Tru Thermometer Calibrator, you may use cleaning brush(es) which are available to purchase on the Accessories page.
    • Turn the unit off and allow it to cool to room temperature before proceeding.
    • Insert the brush to full depth and rotate the brush as you remove it.
    • Repeat this process several times until no matter is observed on the brush.
    • You may dampen the brush slightly with a sanitizing fluid if you wish, but do not use more than enough to dampen the brush.

    Clean the external surfaces of the calibrator with a damp cloth and mild detergent.
    In the event of a malfunction or breakdown, how do I ground the Calibrator to reduce the risk of electrical shock? In the event of a malfunction or breakdown, grounding provides a path of least resistance for the electric current (to reduce the risk of electrical shock). The device is equipped with an electric cord having an equipment-grounding conductor and a grounding plug. The plug must be plugged into a matching outlet that is properly installed and grounded in accordance with all local codes and ordinances.

    Do not modify the plug provided. If it will not fit the outlet, have the proper outlet installed by a qualified electrician.

    Improper connection of the equipment-grounding conductor can result in a risk of electric shock. The conductor with the insulation having an outer surface that is green with or without yellow stripes is the equipment-grounding conductor. If repair or replacement of the electric cord or plug is necessary, do not connect the equipment-grounding conductor to a live terminal.

    Check with a qualified electrician or serviceman if the grounding instructions are not completely understood, or if in doubt as to whether the device is properly grounded.
    Use only 3-wire extension cords that have 3-prong grounding plugs and 3-pole receptacle that accept the device"s plug. Repair or replace damaged or worn cord immediately.
    Calibrator Warranty Tel-Tru warrants each product to be free from defects in material and workmanship under normal use and service for one year from date of manufacture. Please see our full product warranty at Section 8, Warranty, of our Terms and Conditions policy.
    How do I pack the Calibrator for return? Please keep the original carton and packing materials for re-certification service returns.
    Carefully pack your calibrator when shipping it back for re-certification service. See Quick Start Guide.
  • If your are ordering the recertification service via our Customer Support group (585-232-1440 or 800-232-5335), you will obtain a Return Authorization Number (RMA#) from your Tel-Tru associate. Carefully pack up the unit(s), noting the RMA# on the outside of the box, and in the format "RMA XXXX".  Ship the box to the factory at the address listed below.
  • If you are ordering the recertification service via our website, you will find a six-digit order number at the top of your recertification purchase receipt. This is your Thermometer Re-calibration Reference (CR) number. Carefully pack up the unit(s), noting the CR# on the outside of the box, in the format "CR XXXX".  Ship the box to the factory at the address listed below.
  • Ship to: Tel-Tru Manufacturing
    ATTN: Customer Returns, RMA/CR XXXX
    408 St. Paul Street
    Dock @ 10 Ward Street
    Rochester, NY 14605

    Where can I find care and use instructions? For more information visit Tel-Tru Check-Set Calibrators
    I lost the original instructions. Where can I get a replacement? You can print a copy here: Quick Start Guide
    How do I select the correct thermowell for my application? See How to Select Thermowells by viewing our Thermowell brochure.
    Shipping and Returns
    Shipping Policy All online orders are charged a $9.50 shipping fee.
    Currently Tel-Tru does not ship to PO Boxes, APO/FPO, Alaska (AK), Hawaii (HI), Puerto Rico (PW), or International addresses.

    Only domestic Continental United States orders are accepted and processed online via Tel-Tru"s online shopping cart. NON-CONTINENTAL UNITED STATES CUSTOMERS — please consult factory at 585.232.1440 or contact us via the web. Prices, shipping charges, delivery, and availability are subject to change.
    Return Policy Our goal is 100% customer satisfaction. If for any reason you are unhappy with a product purchased from Tel-Tru or wish to cancel an order, please refer to Section 6, Order Cancellation or Changes, of our Terms and Conditions policy.
    What is the procedure for the return or repair of damaged goods? The original buyer must contact Tel-Tru to receive return materials authorization (RMA) number. The item must be returned pre-paid in its original box with the RMA number written on the box. It will be evaluated upon receipt. If an item is repairable and under warranty, Tel-Tru will repair and return it no charge. If the item is not repairable and is still under warranty, Tel-Tru will replace it at no charge. If the thermometer shows signs of abuse, it should not be returned to the factory.
    General Information
    Are calibration certificates and certificate of origin and compliance available? Yes, contact factory for charges (if required) 800-232-5335/585-232-1440. These certificates must be requested on your purchase order with the thermometers or pressure gauges.
    How do you sell your products? We sell our products primarily through distributors and catalog houses that serve industrial, HVAC, food service and other specialized industries. End-users who can not find a Tel-Tru distributor within their area can buy Tel-Tru products online, visit our Shop page.

    Some products are sold direct to original equipment manufacturers (OEMs). Please contact Tel-Tru to select the most appropriate channel of distribution to meet your needs or visit our Distributors page. Call us at 800-232-5335/585-232-1440.
    What is Oxygen cleaning? The service is technically "cleaned for oxygen service". The purpose is to have an instrument free of oil, grease or other impurities. The instrument that is used to measure oxygen must be cleaned to avoid possible explosions. Oxygen and oil do not mix well. Liquid filled gauges are not recommended for this application. The cleaning process involves cleaning the socket and the internal part of the bourdon tube with a chemical solution.
    Can Tel-Tru crossover other companies" product part numbers. Yes, on most items. Contact the factory for more information at 800-232-5335/585-232-1440 or contact us via the web.