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Forehead Thermometer

°C / °F Switch

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.

How do I switch functions?

In “Power On” mode, press and hold the “ON/MEM” button, then press the “SCAN” button, the “HEAD” icon will be switched to icon “” (Scan). You may use the same process to switch back to “HEAD” icon.

Why is my measurement too low or high?

Dirty lens and ambient temperature might affect the measurement. If the lens is dirty, please follow the manual's instruction to clean lens with cotton swab. Besides, we recommend user to place thermometer indoor for 20 minutes to adapt to temperature and get the correct measurement.

Note: User hit the thermometer carelessly might cause the probe lens damage. Please return full package to retailer for service if there is damage.

Why do I get different temperature for continuous measurement? Sometimes in normal, sometimes in lower, sometimes in higher temperature.

The user and thermometer need to adapt to ambient temperature. The rapid temperature change may cause the inaccurate measurement.

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

We recommend user to place thermometer indoor for 15 minutes to adapt to temperature and get the correct measurement.

How to open the battery cover to replace battery?

Please use the incisive tool, for example: Pen tip…And so on. Inserts on battery cover's safely vent,
under the effort presses, simultaneously uses the thumb downward to shove open the battery cover,
then replaces the battery.

(Battery installation picture take TH809 for example. For other models, please refer to the user's manual.)

How do I have my forehead thermometer repaired?

Please send the complete device to the nearest retailer for service.

I lost my forehead thermometer’s manual.

Don’t worry. RADIANT INNOVATION provides consumer online thermometer manuals to download.

The measurement in air conditioning room is different from that in non- air conditioning room?

When thermometer is under rapid temperature change, we recommend user to place thermometer for 15 minutes to adapt to temperature and get the right temperature.

Does forehead mode need to touch body?

Infrared Forehead Thermometer-TH0XF, TH2XF series
Multi-function Thermometer (Forehead Mode)
Please measure close to “the temples” about 0.5 cm distance.

Non-contact Forehead Thermometer-TH30F
Hold the thermometer 1 to 3 cm from “the central forehead”.

Although the thermometer does not touch body, please also follow the instruction for clean and storage to keep accuracy.

What is the normal body temperature?

A normal range for body temperature is 35.8°C ~ 38.0°C (96.4°F ~ 100.4°F). Each person has different temperature, please contact qualified doctor for details.

Here are the normal body temperatures for reference:

Ear Temperature: 35.7°C ~ 37.5°C
Rectal temperature: 35.7°C ~ 37.5°C
Oral temperature: 35.5°C ~ 37.5°C
Armpit temperature: 34.7°C ~ 37.3°C

Body temperature variations affected by age:

0 ~ 2 years: 36.4°C ~ 38.0°C
3 ~ 10 years: 36.1°C ~ 37.8°C
11 ~ 65 years: 35.9°C ~ 37.6°C
  > 65 years: 35.8°C ~ 37.5°C


1. Chamberlain, J.M., Terndrup, T.E., New Light on Ear Thermometer Readings, Contemporary Pediatrics, March 1994.
2. Chamberlain, J.M., et al., Determination of Normal Ear Temperature with an Infrared Emission Detection Thermometer, Annals of Emergency Medicine, January 1995.

What is the standard for fever?

Different site in the body and different thermometers may get different temperatures.
Recommended fever standards stated below:

Site Fever Standard Measuring Time
Oral 37.5 °C 1 min. half - 2 min.
Forehead 37.5 °C Several seconds
Ear 38.0 °C Several seconds
Axillary 37.0 °C 3 min.
Rectal 38.0 °C 1 min. - 1 min. half

Source: Centers for Disease Control , R.O.C.(Taiwan)

Does thermometer need to maintain regularly?

Forehead thermometer is a health care product that needs maintenance, you could use soft cloth to wipe the appearance. Never use benzene for cleaning and never submerge thermometer into water or any liquids. Probe lens is the most delicate part of thermometer, please use cotton swab with alcohol (70%) to wipe it.

Follow the below instruction and video to clean the probe lens.

Probe Lens Cleaning Video

1. Before using the cotton swap with 70% alcohol to wipe the lens, slightly flip the cotton swab to cut down the spare alcohol.
2. If there is no 70% alcohol, use alcohol prep pad to soak the cotton swab.

Important: Do not use sharp pointed object to wipe the lens.

Does summer and winter ambient temperature affect the measurement?

RADIANT INNOVATION thermometer compares ambient temperature and makes compensation. The measurement between 10°C~40°C (50°F~104°F) is the same, but the human body changes a little in different season and different environment. For example, the body temperature becomes hotter after exercise and hot shower.

Why do I have to wait for 6 seconds during constantly measurement?

Wait 6 seconds is to reduce the thermal shock effect result from probe of thermometer contact with ear channel, and hence reduce the chance to affect the accuracy.

Is the thermometer waterproof?
Be careful! The thermometer is not waterproof. Please do not submerge in any liquid and avoid the direct sunlight over 10°C to 40°C (50°F to 104°F) environment.

How long do I have to change thermometer’s battery?

RADIANT INNOVATION thermometer uses a lithium battery (CR2032). Battery life is estimated at 3,000 readings. Enable normal use: 1 year.
The battery life depends on the frequency you use. Please change a new battery when the LCD battery icon flashing.

Does the forehead thermometer I bought only measure forehead temperature?

RADIANT INNOVATION forehead thermometer is designed for forehead temperature measurement. Besides, you may also scan other subject's exterior temperature. For example, you can measure baby's milk or bath water in "SCAN" mode.

Can I measure under sunlight?

The ultraviolet ray in sunlight will damage the forehead thermometer, we recommend user to measure indoor.

Does forehead thermometer radiate infrared?

The forehead thermometer receives the body's infrared and switch to body temperature; therefore, it does not radiate infrared.

Why do I have to measure the temple?
The temporal artery connects to heart via the carotid artery, and it is shallow artery which closes to skin surface. Therefore, we can learn the central body temperature by measuring the skin surface over the temporal artery; also, it is user-friendly measurement. This is where the design concept of forehead thermometer comes from.

Radiant Innovation Inc. was established in year 2000 and mainly focus on Infrared Technology. Our RD, QA, Manufacture Team have been in this field for more than 20 years. Therefore, we are able to provide high-quality & good-design products to all of our customers in the world. There are three product-lines in Radiant in the moment.

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