Read the old alarm before removing it
Photograph the front, back label, wiring, and mounting opening. Record whether the unit is 12-volt hardwired, battery powered, or a combination design. Look up its alert patterns so an active gas or CO alarm is not mistaken for end of life.
Compatibility checklist
The replacement must detect the required hazard and be approved for the RV environment. Check supply voltage, polarity, current draw, connector instructions, mounting orientation, operating temperature, cutout dimensions, audible rating, and certification.
- Propane/LP detection, CO detection, or an explicitly listed combination.
- Correct RV or recreational-vehicle application.
- Compatible power source and wire gauge.
- A visible manufacture date and end-of-life warning.
- A test/reset control accessible after installation.
Understand end of life
CO sensor life is model-specific. Kidde documents seven- or ten-year service lives for different products and explains that an end-of-life chirp persists after battery replacement. In end-of-life mode, the alarm must be replaced because it may no longer detect CO.
Installation height is not universal
LP gas is heavier than air, while CO alarm placement follows the specific listing and manual. Never place a new combination unit in the old opening unless its instructions approve that location for every sensor it contains. If wiring or placement differs, use a qualified RV technician.
Manufacturer material reviewed
These links support the diagnostic order and safety boundaries. Always use the manual for the exact model installed in your RV.