Our COA3910 carbon monoxide detector is designed for reliable safety in the home. If you hear a beep after inserting a new battery and briefly see the FAULT light illuminate, this may be related to the type of battery used.

What causes this?
We have found that some batteries—especially budget brands or batteries with a lower peak voltage—do not always deliver the power required for optimal operation of the detector. This can result in periodic beeping signals and a flashing FAULT light, even though the product itself is otherwise functioning correctly.

Which batteries do we recommend?
For the best performance, we recommend using industrial grade batteries from well-known brands. These provide a stable voltage and have been extensively tested with the COA3910. Recommended options include:

• Maxell Alkaline AA

• Varta Industrial Pro AA

• Duracell Industrial AA

No malfunctions or error notifications have been observed when using these batteries.

Note about alternative batteries
Batteries such as A-Force (often sold at discount stores like Action) may in some cases deliver insufficient voltage, which can cause the symptoms described above. While this does not damage the device, it may lead to confusion and unnecessary alerts.

Tip: To ensure trouble-free operation, always choose quality batteries suitable for safety equipment.

For further questions or advice, we are of course happy to assist.