TEL-TRU LN-250 Operating And Calibrating Instructions

TEL-TRU LN-250 Operating And Calibrating Instructions

Industrial thermometers

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TEL-TRU
MANUFACTURING CO.
MODELS: LN-250, LN-250R, GT-300, GT-300R, GT-400, GT-400R, GT-500, GT-500R, MX-325R, MX-525R,
MM-325R, MM-525R, BC-350R, BC-450R, BC-550R, AA-375R, AA-475R, and AA-575R

CALIBRATING INSTRUCTIONS:

A master thermometer with a high degree of accuracy should be used for calibrating.
Place thermometer to be calibrated alongside a master thermometer. Immerse both thermometers into an
agitated liquid for at least 3 minutes. Compare temperatures. IMPORTANT--For accurate reading therm-
ometer must be immersed PAST GROOVE on lower portion of stem. Master thermometer should also be
immersed to same depth.
NOTE: Models LN-250, GT-300, GT-400, and GT-500 cannot be recalibrated.
LN-250R
1.) Using 5/64" hex key loosen socket head screw (just above hex nut) 1/2 to 1 turn.
2.) Place wrench on hex connecting nut beneath head. Hold head and turn until pointer is at exact temperature.
3.) Tighten socket head screw.
GT-300R, GT-400R, GT-500R, MX-325R, MX-525R,
MM-325R, MM-525R, AA-375R, AA-475R and AA-575R
1.) A socket opening "RESET" is provided on bottom side of the thermometer case.
2.) Insert 1/16" hex key into RESET opening, turn key until pointer is moved to exact temperature.
3.) Remove hex key.
BC-350R, BC-450R and BC-550R
1.) Using 3/32" hex key loosen two socket head screws (just above hex nut) 1/2 to 1 turns.
2.) Place wrench on hex connecting nut beneath head. Hold head and turn until pointer is at exact temperature.
3.) Tighten socket head screws.

GENERAL INFORMATION:

This thermometer is constructed of type 304 stainless steel.
Helix coil is silicone coated on ranges below 500°F for vibration dampening and to maximize heat transfer
and response time.
Glass lens is standard. Other lens options available.
Hermetic seal per ASME B40.3 dustproof and leakproof.
Accuracy is ±1% full span per ASME B40.3 Grade A. Adjustment of the angle between case and stem may
affect accuracy up to 0.5% of span (ASME B40.3).
Over temperature limits - up to 250°F 100%; 250°F to 550°F, 50%; 550°F 1000°F, continuous use up to
800°F, intermittent use over 800°F.
For accurate reading thermometer must be immersed PAST GROOVE on lower portion of stem.
Silicone MSDS available at www.teltru.com/cats/MSDS/TBF9.pdf or contact factory.
Phone: 585-232-1440 • 800-232-5335 • Fax: 585-232-3857 • E-mail: info@teltru.com • Web: www.teltru.com
OPERATING AND CALIBRATING INSTRUCTIONS
Industrial Thermometers
Tel-Tru Manufacturing Company
408 St. Paul Street, Rochester, New York 14605 USA
Quality Products Since 1916
www.teltru.com
Manual 01204003

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Questions and answers

Portie Smith
May 1, 2025

Is tapping the device required?

1 comments:
Mr. Anderson
May 16, 2025

No, tapping is not required for the TEL-TRU LN-250 device.

This answer is automatically generated

Portie Smith
May 1, 2025

How long should a thermometer be left in product to get an accurate temperature?

1 comments:
Mr. Anderson
May 16, 2025

The TEL-TRU LN-250 thermometer should be immersed in an agitated liquid for at least 3 minutes to get an accurate temperature. It must be immersed past the groove on the lower portion of the stem.

This answer is automatically generated

Summary of Contents for TEL-TRU LN-250

  • Page 1 Quality Products Since 1916 www.teltru.com OPERATING AND CALIBRATING INSTRUCTIONS Industrial Thermometers MODELS: LN-250, LN-250R, GT-300, GT-300R, GT-400, GT-400R, GT-500, GT-500R, MX-325R, MX-525R, MM-325R, MM-525R, BC-350R, BC-450R, BC-550R, AA-375R, AA-475R, and AA-575R CALIBRATING INSTRUCTIONS: • A master thermometer with a high degree of accuracy should be used for calibrating.

This manual is also suitable for:

Ln-250rGt-300Gt-300rGt-400Gt-400rGt-500 ... Show all

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