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Safe-T-Alert 25-742 Review: Dual Propane and CO Alarm for RVs

The Safe-T-Alert 25-742 combines a propane sensor and a carbon monoxide sensor in one flush-mount 12-volt RV alarm with a 4.5 by 3.5 inch face and a 3.25 by 2.5 inch cutout. It draws 108 mA, has a low voltage warning, a mute button with a rapid-recovery self-resetting sensor, conforms to UL 2034 RV and UL 1484 RV, meets RVIA and NFPA standards and replaces Atwood 31013 and 31014 alarms without modification.

By the Akermin Editorial Team · 5 min read

Safe-T-Alert 25-742 Review: Dual Propane and CO Alarm for RVs

Safe T Alert · Safe T Alert - Mini Dual LP/CO Alarm - Flush Mount Black - 25-742-BL

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Price and availability are shown on Amazon and can change at any time.

Verdict

The Safe-T-Alert 25-742 is the compact answer to a common RV problem: one wall opening, two hazards. It puts a propane sensor and a carbon monoxide sensor in a single flush-mount 12-volt alarm, which the manufacturer calls its patented Double-Duty Alarm, sized at 4.5 inches wide by 3.5 high by 1.25 deep with a 3.25 by 2.5 inch cutout. It draws 108 mA at 12 volts DC, carries a low voltage warning, has a mute button with a rapid-recovery, self-resetting sensor, is rated from minus 40 to 158 degrees F, conforms to UL 2034 RV and UL 1484 RV, meets RVIA and NFPA standards and replaces Atwood 31013 and 31014 alarms without modification. The listing does not state alarm volume, setpoints or sensor life. For an RV upgrading from a propane-only alarm, or one whose Atwood dual alarm has expired, it is the direct route.

Who It Is For

  • Owners of RVs fitted with an Atwood 31013 or 31014 dual alarm that has reached its replacement date.
  • Owners replacing a propane-only alarm who want to add CO detection without a second opening.
  • Smaller campers and vans where wall space is limited and a full-size dual alarm will not fit.

If you already have a separate CO alarm you trust and only need propane, the 30-442 is the simpler buy.

Documented Specifications

Item Manufacturer or listing statement
Hazards Propane gas and carbon monoxide
Power 12 volts DC, 108 mA; low voltage warning; power-conserving circuitry
Mute Mute button for ventilation; rapid-recovery sensor reactivates if propane or CO remains hazardous; self-resetting
Case 4.5 by 3.5 by 1.25 inches, flush mount, black
Cutout 3.25 by 2.5 inches
Replaces Atwood 31013 and 31014, without modification
Standards Conforms to UL 2034 RV and UL 1484 RV; meets RVIA and NFPA standards
Temperature rating Minus 40 to 158 degrees F
Alarm volume, propane setpoint, CO thresholds, sensor life Not stated on the listing

Two Sensors, One Box

A combined alarm works only because it contains two different sensors. Carbon monoxide is detected by an electrochemical cell, which does not respond to propane or methane; propane is detected by a combustible gas sensor, which does not respond to CO. Neither can stand in for the other. The 25-742 puts both behind one grille and shares the power, the horn and the mute between them. Gas leak detector versus carbon monoxide detector explains the two chemistries, and whether a CO detector detects natural gas clears up the most common misunderstanding.

Placement for Two Gases at Once

Propane is heavier than air and settles on the floor; carbon monoxide has close to the density of air and mixes through the space. A single alarm cannot be in two places, so RV dual alarms mount low, where the propane collects, on the reasoning that CO will reach a low sensor anyway. The manufacturer’s manual gives the height; it is typically within about 12 inches of the floor, near the LP appliances and away from the entry door, furnace outlet and any vent. Do not cover it with a rug or bag. Where to place a propane detector covers the low-mount reasoning in full.

Power, Low Voltage and Mute

At 108 mA the 25-742 draws a little under 2.6 amp-hours per day from the house battery, slightly more than the propane-only 30-442. The low voltage warning matters on a dry-camping trip: a discharged house battery is the most common reason an RV alarm chirps, and the warning is about the battery, not gas. The mute button silences the horn for ventilation, and the rapid-recovery sensor re-arms it if propane or CO remains hazardous; it is self-resetting once the air clears.

The Standards Line

This is one of the few RV alarm listings that states its conformance: UL 2034 RV for the CO side, UL 1484 RV for the gas side, plus RVIA and NFPA compliance, which matters on a vehicle that may be inspected, insured or resold. The listing does not give the propane setpoint in percent LEL or the CO thresholds in ppm; the manual should.

Strengths

  • Propane and CO detection in one compact flush-mount unit.
  • Stated conformance to UL 2034 RV, UL 1484 RV, RVIA and NFPA.
  • Direct replacement for Atwood 31013 and 31014.
  • Mute with automatic re-arm, low voltage warning and a wide temperature rating.

Limitations

  • Alarm volume, propane setpoint and CO thresholds are not stated on the listing.
  • Sensor life is not stated; both sensor types age and the unit will carry a replacement date.
  • Higher continuous draw than a propane-only alarm.
  • A cutout is required; it is not a surface-mount unit.

How It Compares

The Safe-T-Alert 30-442 is the propane-only classic at 90 mA, with a stated 85 dB alarm and a setpoint below 25 percent LEL of propane, in the CCI Controls footprint. The 35-742 is the full-size dual LP and CO flush-mount at 108 mA with a 6.375 by 2.875 inch case, for RVs that have the wider opening. The whole family is compared in the RV gas leak detector roundup; home propane alarms are in the propane detector roundup, and the gas leak detector guide covers the full category. Testing routine for any of them is in how often to test a gas detector.

If Either Sensor Trips

You do not need to know which hazard set it off before you act. Get everyone and pets out of the RV, leave switches, the slide and the generator alone on the way, close the cylinder valve if it is outside and on your path, and call 911 or your propane supplier from a safe distance. An alarm supplements that routine and buys you time; it is not a substitute for it.

How We Research

This review is based on the manufacturer listing and published product information and on patterns in RV owner reports. We did not run laboratory tests. The amp-hour figure is arithmetic from the stated 108 mA draw, and the sensor-chemistry discussion is general background on the product class; where the listing gives no figure, we say so.

Safe T Alert 30 Series Classic LP Gas Alarm - Propane Alarm - Flush Mount, Brown - 30-442-P-BR

Safe T Alert 30 Series Classic LP Gas Alarm -

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Safe-T-Alert by MTI Industries 35-742-BR 35 Series Dual LP/CO Alarm - Flush Mount, Brown

Safe-T-Alert by MTI Industries 35-742-BR 35 Series Dual LP/CO Alarm

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Safe T Alert 20 Series Mini LP Gas Alarm - Propane Alarm - Surface Mount, White - 20-441-P-WT

Safe T Alert 20 Series Mini LP Gas Alarm -

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Products shown because their documented specifications fit this guide. Price and availability are on Amazon and can change.

Frequently Asked Questions

Where does a combined propane and CO alarm go if propane sinks and CO does not?

Low, where the propane is. Carbon monoxide mixes with air rather than layering, so a sensor near the floor still sees it, while a propane sensor near the ceiling would miss a floor-level pool until the RV was badly contaminated. Follow the mounting height in the manual; in most RVs it is the same low position the old alarm occupied.

How can I tell whether the 25-742 is reacting to propane or CO?

The listing does not describe the indication pattern, so the manual is the reference. The immediate response is the same either way: get out, do not operate switches, and call for help from outside. Which sensor tripped is something to establish afterward.

Does the 25-742 replace a 30-442?

Not necessarily in the same cutout. The manufacturer states that the 25-742 replaces Atwood 31013 and 31014 alarms, with a 3.25 by 2.5 inch cutout. The 30-442 listing does not give its cutout size, so measure the existing opening before assuming the mini will cover it.

What do UL 2034 RV and UL 1484 RV mean on the 25-742?

UL 2034 is the standard for carbon monoxide alarms and UL 1484 is the standard for residential gas detectors; the RV suffix indicates the recreational vehicle requirements within those standards. The listing states the alarm conforms to both and meets RVIA and NFPA standards, which is more than most of the propane-only Safe-T-Alert listings state.

Affiliate disclosure: Akermin earns a commission from qualifying Amazon purchases made through links on this page. Our editorial picks are based on documented specifications and owner feedback, not commissions.