For years the Atwood 31011 (now sold as Dometic) was the black 12 V CO and propane alarm in a huge number of RVs. Dometic has discontinued it, and the units we still have are our final allocation. So if yours is chirping, the real question is whether to grab one of the last 31011s or switch to a Safe-T-Alert from MTI Industries. This page compares them using each maker's own manual.
The short answer
- Want an identical swap and the same hole? Buy a genuine Atwood 31011 while our stock lasts. Same wiring, same cutout, nothing to trim.
- Want a model you can still buy next time? The Safe-T-Alert 45-742-BL is the closest match. Atwood's manual lists the 31011 and 31012 as the same black 12 V LP/CO alarm in different packaging, and MTI lists the 45-742-BL as a same-size-cutout replacement for the 31012.
- Old hole damaged or an odd size? The Safe-T-Alert 85-741 universal alarm with trim ring has a 7 x 4 in trim ring that covers a much larger area than the old alarm.
Is the Atwood 31011 the same as the 31012?
Yes, apart from the box. Atwood's LP/CO manual lists four 12 V part numbers for one alarm, model LPCO:
| Part number | Colour | Packaging |
|---|---|---|
| 31011 | Black | OEM (supplied to RV makers) |
| 31012 | Black | Retail |
| 36636 | White | OEM |
| 36681 | White | Retail |
MTI's cross-reference sheet lists the Safe-T-Alert 45-742-BL for the 31012 and the 45-742-WT for the 36681, both noted as the same size cutout. That makes the 45-742 the natural Safe-T-Alert route for a 31011 too. Do not confuse these with the Atwood 31013, 31014 and 36720: those are propane-only alarms, and MTI matches them to different Safe-T-Alert models (see our Safe-T-Alert replacement chart).
Atwood 31011 vs Safe-T-Alert 45-742: side by side
| Atwood / Dometic 31011 | Safe-T-Alert 45-742-BL | |
|---|---|---|
| Detects | CO and propane | CO and propane |
| Availability | Discontinued by Dometic; limited stock | Current MTI model |
| Mounting | Flush (surface with Atwood's optional surface box) | Flush (the 45-741 is the surface version) |
| Face size | 3 7/16 in W x 3 9/16 in H | 4.75 x 4.75 in, 1.25 in deep |
| Wall cutout | About 3.5 in W x 3 5/8 in H, 1.5 in clear behind the wall; 4 corner screws | MTI's manual: 3.5 x 2.5 in, 1 in clear behind the wall; 2 screws at the ends of the case |
| Wires | 3: red +12 V, a second red for an optional second battery, black ground | 2: red +12 V, black ground |
| Power | 12 V DC | 12 V DC; works down to 7 V; 108 mA |
| Service life | 7 years of powered operation | 5 years |
| End-of-life signal | 2 quick beeps every 5 seconds; mute for 48 hours, then it cannot be silenced | 1 chirp every 25 to 30 seconds; mute for 72 hours at a time, for up to 30 days |
| After muting a gas alarm | Re-alarms after about 6 minutes if gas remains | CO: about 6 minutes; propane: about 5 minutes |
| Mounting height | No more than 18 in off the floor | 4 to 20 in off the floor |
| Standards | UL 2034 and UL 1484; CSA 6.19 | UL 2034 and UL 1484 |
| Warranty | 2 years limited | 1 year limited |
Specs for the 31011 are from Atwood's LP/CO user's manual (P/N 30094); specs for the 45-742 are from MTI's 45 Series manual. Atwood's manual gives two different current-draw figures for the 31011, so we have left that out.
What the differences mean
Fitting a 45-742 into a 31011 hole
Atwood's cutout (about 3.5 x 3 5/8 in) is taller than the one MTI tells you to cut for a new 45-742 (3.5 x 2.5 in), so you will not need to enlarge the hole. The 45-742's 4.75 in square face is bigger than the 31011's face, so it covers the old opening and any paint line around it. MTI's cross-reference calls the 31012 swap the same size cutout; check that the 45-742's two end screws land on solid wall before you drill, and measure your hole first. If anything does not line up, the trim ring on the 85-741-BL-TR covers a larger area (7 x 4 in overall).
The extra red wire
The 31011 has a second red lead for an optional second battery; Safe-T-Alert alarms have one power lead. MTI's instructions for replacing a two-lead Atwood or CCI alarm: connect the Safe-T-Alert red wire to the house (coach) supply, and cut and cap the other lead. Connecting both will drain the chassis battery. Black goes to ground on both. Full details are in our Safe-T-Alert manual, reset and wiring guide.
Five years vs seven
The 31011 is built to run for 7 years; every Safe-T-Alert is built for 5, and MTI says to replace its alarms after 5 years. Both stop working by design at the end, so the longer life is a real point in the 31011's favour. Weigh it against the fact that you will not be able to buy another 31011 when that one expires. See when to replace an RV CO and propane alarm.
Different chirps
If you switch, the sounds change. A 31011 at end of life gives 2 quick beeps every 5 seconds; a Safe-T-Alert gives a single chirp every 25 to 30 seconds with red-red-green-green lights. Both use 4 beeps then a pause for a CO alarm. Our Safe-T-Alert lights and beeps guide lists every pattern.
Placement stays the same
Both makers want a combination alarm low on the wall because propane sinks: Atwood says no more than 18 in off the floor, MTI says 4 to 20 in. An alarm in the 31011's original spot will normally suit the Safe-T-Alert too.
Other Safe-T-Alert options
| If you want | Consider |
|---|---|
| The closest swap for a black 31011 | 45-742-BL; white: 45-742-WT |
| A trim ring to cover a damaged or larger hole | 85-741-BL-TR universal |
| A smaller flush alarm and you are happy to patch the wall | 25-742-BL Mini, our best-selling Safe-T-Alert; 3.5 x 2.75 in cutout |
| A surface-mount alarm instead | 45-741-BL |
Sizes for every model are in the Safe-T-Alert size guide.
Frequently asked questions
What replaces the Atwood 31011?
The same 31011 while stock lasts, or the Safe-T-Alert 45-742-BL, which MTI lists as a same-size-cutout replacement for the Atwood 31012, the retail-packaged version of the same alarm.
Is the Atwood 31011 discontinued?
Yes. Dometic has discontinued it, and the units we have are our final allocation with no restock coming.
Is Safe-T-Alert as good as Atwood?
Both are listed to the same standards for RV alarms, UL 2034 for CO and UL 1484 for propane. The 31011 has a longer service life (7 years vs 5) and a longer warranty (2 years vs 1); the Safe-T-Alert is in current production.
Can I use the 31011's wiring for a Safe-T-Alert?
Yes. Red to the house +12 V supply, black to ground, and cap the 31011's second red lead.
Does the Safe-T-Alert mount at the same height?
Yes. Both are combination alarms meant to sit low on the wall: 4 to 20 in off the floor for Safe-T-Alert, no more than 18 in for Atwood.
Every alarm on this page ships from our warehouse in Upland, California. Not sure which one replaces yours? Send us a photo of the old alarm and its label before you order and we will match it. Browse the full Safe-T-Alert range or all RV safety detectors.