Important “FAULT” Signals & Service Information



When the C O – Experts Low Level C O “Health” Monitor emits a single beep, [one beep at a time], this is a “Fault Warning”, NOT A Notice of C O being detected.
After the single beep is emitted, the display will show one of four messages for FIVE, 5, seconds. The displayed Warning will be one of four messages:


  1. “bAT” … Indicating that the battery needs to be replaced.
  2. “bae”… Monitor has developed a serious electrical “Short” that will quickly drain the battery, usually after being dropped.
  3. “ERR” … Indicates that the failsafe electronic self-test system has detected an electronic malfunction within the Monitor or in the Sensor.
  4. “Sensor End” Warning… which is your notice that the Monitor is NO LONGER protecting you from C O, not even at Extremely High Levels and needs to be replaced AT ONCE.


Automatic Fault Detection

In the unlikely event of a fault developing in your Monitor, it will emit one single Beep per minute.
If this happens DO NOT OPEN THE Monitor, there are no user serviceable parts inside, and opening the Monitor will automatically VOID your warranty.

Normally if your Monitor is three years old or more, I suggest you replace it with a new model rather than pay the $73. _ minimum repair fee.

Your replacement charge for a new C O Monitor would be $179. _ with free shipping.
If you decide to order a new C O Monitor I will need for you to put a note in with your check telling me the Serial number on the old Monitor that you are replacing.

Please make your check payable to:
ULTRA Low Level Monitors, LLC
19299 Katrina Lane, Unit “B”
Eldridge, MO 65463 USA
E- mail:



CO Experts – 19299 Katrina Lane; Eldridge Missouri 65463-9102

Tel: 1-888-443-5377 Fax: 1-888-436-5377

CO Experts
19299 Katrina Lane – Eldridge Missouri 65463-9102
Tel: 1-888-443-5377 Fax: 1-888-436-5377