Exergen TemporalScanner screen: what LO A, HI A, LO, HI, Err, nc and con mean
Exergen’s instructions for use for the TemporalScanner TAT-2000C Dual Mode name every state below. Each one has Exergen’s own words in quotation marks, what Exergen says to do, and a link to our page on the same symbol across other makes.
Check your thermometer’s manual — makers differ.
All 10 Exergen screen states at a glance
| On the screen | What Exergen’s manual says it means |
|---|---|
LO A (printed LO.A) | The thermometer itself is too cold |
HI A (printed HI.A) | The thermometer itself is too warm |
LO | The temperature measured is below the range |
HI | The temperature measured is above the range |
Err | Radio interference stopped the reading |
Blinking battery icon with a temperature | Battery low, readings still correct |
Blinking battery icon with 2 dashes | Battery too low to measure |
nc | Non-contact mode |
con | Contact mode |
loud or Shh | Beeper and light on, or quiet mode |
Which models this covers
The manual read here is the TAT-2000C Dual Mode (document 818805 rev 4) from Exergen’s own site. Its Display Messages table prints each message as a picture of the screen (HI, LO, HI.A, LO.A, Err, nc, con); the meanings are the words beside them. Other TemporalScanner models have their own manuals.
Each state, in Exergen’s words
LO A (printed LO.A) The thermometer itself is too cold
“Temperature of the thermometer is lower than 60°F (15.5°C).”
What Exergen says to do: “Let the instrument acclimatize for about 30 minutes in a warmer area in which it will be used.”
The A is about the thermometer, not the patient: LO A after a cold car or a cold room means wait, not re-measure straight away.
Every make: Room too hot or too cold. Source: Exergen TemporalScanner TAT-2000C Dual Mode — instructions for use (818805 rev 4, PDF) Checked 2026-10-13.
HI A (printed HI.A) The thermometer itself is too warm
“Temperature of the thermometer is higher than 104°F (40°C).”
What Exergen says to do: “Let the instrument acclimatize for about 30 minutes in a cooler area in which it will be used.”
Exergen’s operating range for the thermometer is 16 to 40 °C (61 to 104 °F).
Every make: Room too hot or too cold. Source: Exergen TemporalScanner TAT-2000C Dual Mode — instructions for use (818805 rev 4, PDF) Checked 2026-10-13.
LO The temperature measured is below the range
“Temperature measured is lower than 60 °F (15.5 °C).”
Exergen’s floor is far lower than the 34 °C forehead floor that Omron’s ET720 and Beurer’s FT 95 manuals give. LO is not a temperature either: the reading was below the TAT-2000C’s range.
Every make: Lo on a thermometer. Source: Exergen TemporalScanner TAT-2000C Dual Mode — instructions for use (818805 rev 4, PDF) Checked 2026-10-13.
HI The temperature measured is above the range
“Temperature measured is higher than 107.6 °F (42 °C).”
HI is not a temperature: it means the reading is above the top of the TAT-2000C’s range, which Exergen gives as 16 to 42 °C (61 to 107.6 °F).
Every make: Hi on a thermometer. Source: Exergen TemporalScanner TAT-2000C Dual Mode — instructions for use (818805 rev 4, PDF) Checked 2026-10-13.
Err Radio interference stopped the reading
“EMI/RFI (like static on a radio) protection is preventing a temperature from being taken.”
What Exergen says to do: “Wait a minute and try again. If not, reset by removing and replacing the battery. Be sure battery is tightly connected. Call Customer Service if error message reappears.”
EMI/RFI means electromagnetic or radio-frequency interference, the kind a nearby phone or radio set can cause.
Every make: Err or Er with a number. Source: Exergen TemporalScanner TAT-2000C Dual Mode — instructions for use (818805 rev 4, PDF) Checked 2026-10-13.
Blinking battery icon with a temperature Battery low, readings still correct
“Blinking battery icon with temperature displayed: battery is low but will still operate correctly. Replace soon.”
The TAT-2000C takes one alkaline 9-volt battery.
Every make: Low battery symbol. Source: Exergen TemporalScanner TAT-2000C Dual Mode — instructions for use (818805 rev 4, PDF) Checked 2026-10-13.
Blinking battery icon with 2 dashes Battery too low to measure
“Blinking battery icon with 2 dashes: not enough energy in the battery to measure correct temperature. Replace battery.”
The two dashes take the place of the number: no reading was taken.
Every make: Low battery symbol. Source: Exergen TemporalScanner TAT-2000C Dual Mode — instructions for use (818805 rev 4, PDF) Checked 2026-10-13.
nc Non-contact mode
“Press the button to turn on. nc will be on the display.”
“A flickering nc on display is visible during measurement in Non-Contact mode.”
Exergen says non-contact mode is calibrated to read an oral approximation, and not to use it if the forehead is perspiring.
Every make: Body, forehead, object or room mode symbol. Source: Exergen TemporalScanner TAT-2000C Dual Mode — instructions for use (818805 rev 4, PDF) Checked 2026-10-13.
con Contact mode
“Press the button again to enter Contact mode. The display will change to con.”
“A flickering con on display is visible during measurement in Contact mode.”
Exergen says contact mode reads core arterial temperature, comparable to rectal temperature, and should be used if the patient shows signs of illness.
Every make: Body, forehead, object or room mode symbol. Source: Exergen TemporalScanner TAT-2000C Dual Mode — instructions for use (818805 rev 4, PDF) Checked 2026-10-13.
loud or Shh Beeper and light on, or quiet mode
“To turn the beeper and front LED back on, repeat step 1 to find Shh then step 2 to change into loud.”
In Shh the beeps and the front light that track the reading are off; the reading itself is unchanged.
Source: Exergen TemporalScanner TAT-2000C Dual Mode — instructions for use (818805 rev 4, PDF) Checked 2026-10-13.
These pages report what each maker’s manual says and quote it wherever health is involved. They do not diagnose anything, they are not medical advice, and they do not tell you whether a temperature is a fever or what to do about it; only your own thermometer’s manual and your doctor or nurse can do that for the person you are looking after.
Other thermometer makers
Sources
Every state above is quoted from this document on Exergen’s own website, fetched and read on the date shown. Words in quotation marks are Exergen’s; everything else is ours.
- Exergen: Exergen TemporalScanner TAT-2000C Dual Mode — instructions for use (818805 rev 4, PDF) Checked 2026-10-13.