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An RV combination alarm is life-safety equipment, not a cosmetic upgrade. The Safe-T-Alert 35-742 is a flush-mount, hardwired 12-volt detector intended to warn about both carbon monoxide and propane gas in an RV environment. It can be a sensible replacement only when its model, opening, wiring, location and date requirements match your coach.
Important counterfeit warning
Manufacturer MTI Industries warns that counterfeit products labeled as model 35-742 have appeared in online stores, including listings from some Amazon sellers. Buy only a genuine, current-date unit from an authorized or clearly reputable seller. When it arrives, verify the seller, packaging, model number, manufacturing or replacement date, labeling and documentation before installation. If anything looks questionable, do not install it—contact MTI Industries.
What the 35-742 is designed to do
- Combines carbon-monoxide and propane-gas detection in one flush-mount alarm.
- Runs from the RV’s 12-volt electrical system rather than relying on a household-style plug.
- Includes mute and rapid-recovery functions, according to the manufacturer.
- Is designed and tested for the vibration, temperature and humidity conditions found in RV use.
Before ordering
- Read the existing alarm’s label. Match the exact model or use only a replacement explicitly approved by the manufacturer.
- Measure the opening and faceplate. “Flush mount” does not mean every alarm fits every cutout.
- Confirm voltage and wiring. This is a 12-volt hardwired device. Wire colors and connectors can vary by coach and production year.
- Check the installation location. Propane and carbon monoxide behave differently; follow the supplied placement instructions rather than relocating the alarm by guesswork.
- Check the date. Life-safety alarms have a service life. Avoid old stock and record the replacement date where you can find it later.
Confirm that the listing is genuine, current-date stock from an authorized or reputable seller before buying.
Installation and testing
Disconnect shore power and the appropriate 12-volt circuit before working. Take a clear photo of the old wiring before removal, follow the new alarm’s instructions exactly, and use proper electrical connections. If the wiring, fuse, mounting position or replacement model is uncertain, use a qualified RV technician.
After installation, restore power and perform the alarm’s prescribed test. Teach every traveler what each tone or indicator means. Test on the manufacturer’s schedule and before trips. Never paint, cover, silence permanently or remove power from an alarm that is sounding.
What this alarm cannot replace
A detector does not replace annual propane-system inspection, combustion-appliance service, adequate ventilation or safe generator and heater use. If an alarm sounds, follow the manufacturer’s emergency instructions, move people and pets to fresh air, shut off ignition sources only if it is safe, and contact emergency services or a qualified technician. Do not re-enter merely because the alarm stops.
Our take
The 35-742’s dual sensing and flush-mount format make it worth considering for a compatible RV. The buying decision hinges less on convenience than on authenticity, model compatibility and fresh manufacturing date. Treat those checks as mandatory.
Primary source: MTI Industries 35 Series product information and MTI Industries counterfeit-product warning. Specifications and instructions can change; verify the current documentation supplied with your alarm.