CO alarm chirps every 60 seconds with the red LED flashing

Possible cause: Low batteries. Replace the batteries as soon as possible.

The CO alarm gives two chirps every half-minute alongside a double flash of its red LED

Possible cause: The alarm has reached the end of its life. Replace the alarm.

CO alarm chirps every 30 seconds with the red LED flashing every 30 seconds

Possible cause: A fault with the alarm. Replace the alarm.

CO alarm's red LED is on with a constant tone

Possible cause: A malfunction with the alarm. Replace the alarm.

CO alarm sounds a loud, continuous tone with the red LED lit

Possible cause: Dangerous levels of carbon monoxide have been detected. Follow the emergency procedures described in the handbook (evacuate, ventilate, and don't return until the alarm clears).

Smoke alarm sounds erratic or low

Possible cause: This can indicate a defective alarm. Return the smoke alarm for service

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Elddis • Casita • Smoke & CO Alarms

Casita models: 462, 550, 554, 586, 840, 860, 866

Elddis Smoke & CO Alarms

(Casita, 2018 Model Year)

Master Troubleshooting & Diagnostics Matrix

Error Code / Indicator	Symptom / Meaning	Possible Cause	Step-by-Step DIY Fix	Suggested Actions
`N/A`	CO alarm chirps every 60 seconds with the red LED flashing	Low batteries	Replace the batteries as soon as possible.	DIY Safe
Recommended partsAffiliate linksView 2 optionsHide Check which battery type your CO alarm takes (look at the batteries fitted now), then choose the matching pack: The handbook doesn't say which battery this alarm uses. Most caravan CO alarms take AA or 9V batteries, so check yours before ordering. AA batteriesDuracell Plus AA Alkaline Batteries (12 Pack) 1.5V, LR06~£9.00 for 124.7★ (71,000+ ratings), dispatched/sold by Amazon View on Amazon → 9V batteryDuracell Plus 9V Alkaline Batteries (2 Pack) 6LR61~£6.50 for 24.7★ (15,000+ ratings), dispatched/sold by Amazon View on Amazon →
`N/A`	The CO alarm gives two chirps every half-minute alongside a double flash of its red LED	The alarm has reached the end of its life	Replace the alarm.	DIY Safe
`N/A`	CO alarm chirps every 30 seconds with the red LED flashing every 30 seconds	A fault with the alarm	Replace the alarm.	DIY Safe
`N/A`	CO alarm's red LED is on with a constant tone	A malfunction with the alarm	Replace the alarm.	DIY Safe
`N/A`	CO alarm sounds a loud, continuous tone with the red LED lit	Dangerous levels of carbon monoxide have been detected	Follow the emergency procedures described in the handbook (evacuate, ventilate, and don't return until the alarm clears).	DIY Safe
`N/A`	Smoke alarm sounds erratic or low	This can indicate a defective alarm	Return the smoke alarm for service	Professional Intervention Required