Question:
I had metiond part of this in a reply to a thread, but have expanded on it here....in case you missed the thread..

I just got a 10 year old RV and have been checking out and finding some small repairs to do, no problem... i did notice my smoke detector was not working properly nor my LP alarm...

so..

I purchased a First Alert SC01 Smoke and Carbon Monoxide Alarm as my current smoke detector alarm noise was barely audiable...even with new battery...

I thought a combo unit for $40 was the way to do, i did not see any smoke detectors in my Camping World Catalog, but did see Carbon Monoxide for about $40.... so killing two birds with one stone...

I opened the box and looked at the manual and it said "It is not designed for marine or Rv use" then it mentions all the things and how far away your supposed to be from them, which is impossible in a 21' Class C..... so Do i use this, i'm concerned about safety...? Will it work? Has anyone used this one, did it work? Do i buy one each at $40, but which smoke detector, do i rip open boxes at the store to see if they are RV rated...? Do i go to a Boat Store and look for smoke and co alarms?

OH, my LP alarm, alarms when you turn it on and keeps alarming, so its time for that one to be replaced also.... any ideas? I did see two at Camping World.

Answer: I think the CO detector will probably work fine, but as far as a combo unit - probably not a good idea. First, in general, you want the CO unit mounted close to your head when you're sleeping, not necessarily where you want a smoke detector. Second, our smoke detector goes off whenever we cook certain things, and we never learn to disable it - we just rip it off its mount and whip out the battery. I don't want to be doing that with the CO detector at the same time, and I want no confusion over which one is going off! By and large, you will find parallel reasoning can be used to find an argument against a combo anything - it is rarely a good idea. As for LP - can't help you there, as we don't have one. If a 12V model, just make sure its current drain is low.