Radiantek TH859S Manual

** Replace the probe cover after each use to ensure 

an accurate reading and avoid cross contamination.     

TH859S Ear-Type Thermometer 

Thank you for purchasing the thermometer. This thermometer is 

designed with an advanced infrared and ambient temperature 

compensation technology for instantaneous self-diagnosis and 

accurate temperature measurements. Do not use this device for 

Live & Dead decision or Safety related applications. Please 

consult with doctor if you have health concerns. 

Operating Instructions:

NOTE：The device must stay in stable ambient (room)     

temperature for 15 minutes before operating. 

1.  Gently squeeze the opposite ends of the thermometer to pull 

off the probe cap. Do not use force to remove the cap. 

2.  Always use a new and undamaged probe cover.     

Make sure the ear canal is clean.

  Warning: Choking from swallowing small parts and batteries by children or pets is possible, please keep small     

            parts and batteries at places where children and pets can’t reach. 

3.  Install Probe Cover   

1)  Place a new probe cover on the connection ring. (See Figure 1) 

NOTE：Make sure to place the “Adhesive Side” of probe cover “Upward.”

2)  Align the probe with the center of probe cover. Insert the probe into the probe cover on the connection ring.   

(See Figure 2)

3)  Push the connection ring until the “Click” sound. This means the probe cover has been installed successfully. 

NOTE：If the probe cover did not connect firmly, the “ ” icon will flash 

  on the LCD screen. Please check the setting of the probe cover again.

    Proper installation of the probe cover and using the specific probe cover ensure accurate measurements. 

4.  Press “ON/MEM” button to power on. The thermometer is ready for use after the ear icon stop flashing and two short beep 

sound. 

5.  Gently pull the ear back to straighten the ear canal and snugly position the   

probe into the ear canal, aiming towards the membrane of the eardrum to obtain   

an accurate reading. ( Fig.4-1)

6.  Measuring the ear temperature：Use the index finger to trigger. Press the “Scan”   

button until you hear a long beep. ( Fig.4-2 ).

7.   Power off：This device will automatically shut down after 1 minute pending to extend battery life.   

NOTE：

a. Before the measurement, please stay in a stable environment for 5mins and avoid the exercise, bath for 30mins.   

b. It is recommended that you measure 3 times with the same ear. If the 3 measurements are different, select the   

highest temperature. 

c. To avoid the risk of cross contamination, please clean the probe according to “Cleaning and Storage” section after   

each use. 

      d. The "Clinical Bias” is -0.2 ~ -0.4°C. 

e. The "Limits of Agreement” is 0.58. 

f. The "Repeatability” is 0.17°C. 

Fever Alarm:   

If the thermometer detects a body temperature  ≧37.5°C (or 99.5°F), three short beep sound will follow one long beep sound to 

warn the user for potential fever.

Switching between Fahrenheit(°F) and Celsius(°C):  

In “Power Off” mode, press and hold the “SCAN” button, then press the “ON/MEM” button for 3 seconds, icon “°C” will be switched 

to icon “°F”. You can also use the same process to change the LCD display from °F to °C.

Memory Function: 

When in power on, press the “ON/MEM” button to see the temperature stored. The thermometer provides 9 sets 

memory for the body temperature. 

Cleaning and Storage: 

The probe is the most delicate part of the thermometer. Use with care when cleaning the lens to avoid damage.

Storage temperature Range: It should be stored at room temperature between -20~+50°C, RH≦85% 

Keep the unit dry and away from any liquids and direct sunlight.   

The Probe should not submerge into any liquids. 

** If device is accidentally used without probe cover, clean the probe as follows: 

a. Please use the cotton swab with Alcohol (70% concentration) to clean the lens( on the inside of the probe). 

b. Allow the probe to fully dry for at least 1 minute. 

NOTE：Please check the device if damaged once it falls. If you can’t make sure of it, please send the complete device to the nearest 

retailer for recalibration. 

Holding the thermometer too long may cause a higher ambient temperature reading of the probe.   

This could make the body temperature measurement lower than usual.

Changing the Battery: 

This device is supplied with one lithium cell (CR2032 x 1).

○

1

Open the battery cover: Insert a pointed object into the battery cover pick hole. At the same time, use thumb to remove battery 

cover. (See Figure 1)  ○

2

Flip the battery out with a small screw driver (See Figure 2)  ○

3

  Insert the new battery under the metal 

hook on the left side and press the right side of the battery down until you hear a “click”. (See Figure 3)  ○

4

Replace the battery 

cover 

  The positive (+) side Up and the negative (-) side pointed Down.  

Specifications: 

Temperature measurement range: 34~42.2°C (93.2~108°F) 

Operating temperature range: 10~40°C (50~104°F) , 15%~85% RH 

Storage temperature Range: It should be stored at room temperature between -20~+50°C , RH≦85% 

Transportation temperature shall be less than 70°C, RH≦95% 

Atmospheric pressure: 800~1013 hPa 

Comply with ASTM E1965-98, EN ISO 80601-2-56, IEC/EN60601-1-2(EMC), IEC/EN60601-1(Safety) standards, ISO10993, 

RoHS. 

Accuracy: ±0.2°C (0.4°F) within 35~42°C (95~107.6°F), ±0.3°C (0.5°F) for other range. 

This thermometer converts the ear temperature to display its “oral equivalent.”

(according to the result of the clinical evaluation to get the offset value) 

Figure 4-1 

Figure 4-2 

Figure 

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2 

Figure 

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Figure 

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Figure 

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