A Safe-T-Alert alarm has a single button and two wires, but what that button does depends on what the alarm is telling you. Pressing it can mute a gas alarm, run a self-test, show a stored CO reading, or silence the end-of-life chirp for a few days. This guide pulls the reset, mute, test, wiring and mounting instructions out of MTI's own Safe-T-Alert manuals, with a link to the manual for each current model at the end.
If the alarm is sounding a gas or CO pattern, treat it as real. MTI's manuals say to press the Test/Mute button, not to disconnect power, get everyone out into fresh air, and turn off the propane at the tank. Do not use the RV's gas appliances until the source is found and fixed.
The TEST/Mute button: what one press does
MTI's manuals call it TEST/RESET, TEST/Mute or the Test/Mute switch; the product pages call it the Alarm Mute button. It is the same button. What happens when you press it depends on the alarm's state:
| What the alarm is doing | What a press does (per MTI) |
|---|---|
| CO alarm: 4 beeps, 5 seconds off, red light | Mutes the horn. The red light stays on until the CO clears. If CO is still present, the alarm sounds again after about 6 minutes. |
| Propane alarm on a combination (CO + propane) alarm: constant horn, flashing red | Mutes the horn. If propane is still present, it sounds again after about 5 minutes. |
| Propane alarm on a 20 or 30 Series propane-only alarm | Mutes the horn for about 90 seconds; it re-alarms if gas is still present. |
| Malfunction signal: single beep at intervals, alternating red and green | Try to reset it with a press. If it will not clear, check the RV battery voltage. If the voltage is good, MTI says to remove the alarm and return it. |
| End of life: single chirp every 25 to 30 seconds, red-red-green-green lights | Silences the chirp for 72 hours (3 days). You can repeat this for up to 30 days, after which it can no longer be silenced. The alarm must be replaced. |
| Normal: steady green, no sound | Hold for 1 second to run the self-test (see below). |
For the full list of light and sound patterns, see Safe-T-Alert beeping? What the lights and beeps mean.
How to reset a Safe-T-Alert
After a real gas or CO alarm
- Press TEST/Mute to silence the horn, but leave the alarm powered.
- Get everyone out, turn off the propane at the tank, and ventilate.
- Find and fix the cause before using gas appliances again. If anyone feels unwell, get medical help.
- There is nothing else to reset. On a CO alarm the red light stays on until the CO clears, then the alarm goes back to steady green. If it sounds again after the muted period, gas or CO is still present.
The end-of-life chirp
There is no way to reset end of life. Every Safe-T-Alert has a 5-year service life, and the UL and CSA standards require the alarm to stop service when that is reached. The 72-hour silence is there to give you time to get a replacement, and MTI says not to disconnect the old alarm until the new one is on hand. See when to replace an RV CO and propane alarm.
A 20 or 30 Series propane alarm that goes off with no gas present
If a 20 or 30 Series alarm sounds after warm-up and there is no propane, MTI's troubleshooting chart lists a contaminated sensor. Press Test/Mute and wait 90 seconds. Only do this once you are sure there is no leak: if you smell gas, treat the alarm as real. If the alarm keeps sounding with no gas present, replace it.
Is there a hard reset?
MTI does not publish a power-cycle reset procedure, and its manuals say not to disconnect power during an alarm. If you switch the 12 V supply off and back on for another reason (for example after storage), the alarm goes through its warm-up again: a flashing green light for up to 10 minutes on CO and combination alarms, and about 1 to 2 minutes for propane sensing.
62 Series CO alarm: reading the stored CO level
The 62 Series CO alarm (MTI calls it Memory Scan) stores the peak CO level it has seen. A short press of TEST/RESET, under 1 second, shows it:
- 1 chirp, 1 green blink: memory clear
- 2 chirps, 2 red blinks: peak below 100 ppm
- 3 chirps, 3 red blinks: peak below 200 ppm
- 4 chirps, 4 red blinks: peak above 200 ppm
This is useful if the alarm went off while nobody was in the RV. MTI's manual does not describe a way to clear the memory, so if you need to, call MTI.
How to test the alarm
- Check the date code. Replace any propane or CO alarm more than 5 years old.
- Press and hold TEST for 1 second. The light turns red and the horn sounds (on CO and combination alarms, 4 beeps; on combination alarms the gas light also blinks red). This tests the electronics only, not the sensors.
- Test the propane sensor with propane or butane gas. The alarm can take up to 10 seconds to sound.
- Test the CO sensor with Safe-T-Alert CO test gas, which checks the 400 ppm alarm point. Never try to make CO to test the alarm.
MTI says to test after storage, before each trip, and at least weekly while the RV is in use. If an alarm does not test properly, replace it.
Safe-T-Alert wiring
Every current Safe-T-Alert RV alarm is hard-wired to the coach's 12 V DC supply. There is no battery inside. MTI's manuals for the 20, 25, 30, 35, 45, 62 and 85 Series all use the same two wires:
| Alarm wire | Connect to |
|---|---|
| Red | +12 V, on a fused circuit |
| Black | Ground (negative) |
- Circuit: use a circuit that cannot be switched off by a wall switch or a ground-fault device. MTI says it is acceptable to wire it through the RV's main battery disconnect, but the RV must not be occupied while the disconnect is off, because the alarm is off too.
- Fuse: MTI gives 15 A as the maximum circuit protection. The 20 and 30 Series manuals recommend a 1 A in-line fuse.
- Wire size: 14 gauge per the 20 and 30 Series manuals; 14 to 18 gauge per the 25, 35 and 62 Series manuals.
- Voltage: 12 V DC nominal. MTI's manuals say the combination and 62 Series alarms keep working down to 7 V and the 20 and 30 Series down to 8 V.
- Current draw: 108 mA for the combination alarms and 37 mA for the 62 Series CO alarm. MTI's figures for the propane-only 20 and 30 Series vary between its manuals and web pages (75 to 100 mA).
- Polarity matters. MTI's troubleshooting charts list reversed wiring as a reason for a dead green light.
Replacing an Atwood or CCI alarm with two power wires
Some Atwood and CCI alarms have two power leads, one from the house battery and one from the chassis battery. A Safe-T-Alert has one. MTI says to 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.
Alarms that control a propane solenoid valve
The 25-742-R kit adds a relay and a solenoid valve so the alarm can shut off the LP supply. Wire it from the instructions packed with the kit, and use only the solenoid supplied with it. MTI warns never to connect a Safe-T-Alert alarm to a solenoid valve controlled by a CCI propane alarm, because of a burn or fire risk; the CCI alarm and its valve have to be replaced together. If you are unsure what you have, send us a photo before you order.
Where to mount it
- Propane and combination alarms (20, 25, 30, 35, 45, 80 and 85 Series): 4 to 20 inches above the floor, because propane is heavier than air, near possible leak sources such as the furnace, refrigerator, range or oven.
- 62 Series CO alarm: at any height at least 4 inches off the floor, outside the sleeping area.
- Do not install: behind furniture or drapes, inside closets, within 12 inches of a window that opens, an exterior door or a heating or return vent, or on an outside wall.
- Flush mount: switch off the 12 V supply, cut the opening (MTI's manuals call for about 1 inch of depth behind the wall), connect red and black, and fasten the alarm with the two screws at the ends of the case. Check the cutout against the manual for your exact model before you cut; our Safe-T-Alert size guide lists the case sizes.
- Surface mount: the alarm mounts on a back plate, with a half-inch hole in the wall for the leads.
- Put the warning label that comes with the alarm within 24 inches of it.
For a step-by-step swap of an old hard-wired alarm, see how to replace an RV carbon monoxide and propane detector.
Safe-T-Alert manuals by model
MTI Industries hosts the owner's manuals on its website, safetalert.com. Each one covers installation, wiring, testing and troubleshooting for that series.
| Series | Models we stock | MTI manual |
|---|---|---|
| 20 Series propane | 20-441-P | RV 20 Series manual (PDF) |
| 30 Series propane | 30-441-P, 30-442-P | RV 30 Series manual (PDF) |
| 25 Series Mini CO + propane | 25-741, 25-742, 25-742-TR, 25-742-R kit | RV 25 Series manual (PDF) |
| 35 Series CO + propane | 35-741, 35-742 | RV 35 Series manual (PDF) |
| 45 Series CO + propane | 45-741, 45-742 | RV 45 Series manual (PDF) |
| 85 Series universal CO + propane | 85-741-TR | RV 85 Series manual (PDF) |
| 62 Series CO | 62-541, 62-542-TR | RV 62 Series manual (PDF) |
| 80 Series universal propane | 80-441-TR | Not posted on MTI's site; call MTI for a copy |
MTI customer service: 800-383-0269, or the contact form at safetalert.com.
Frequently asked questions
How do I turn off a beeping Safe-T-Alert?
Press the TEST/Mute button. During a gas or CO alarm, that mutes the horn for a few minutes while you ventilate; it will sound again if gas is still there. For the end-of-life chirp, it buys 72 hours at a time for up to 30 days. MTI says not to disconnect power during an alarm.
How do I reset a Safe-T-Alert carbon monoxide detector?
Press TEST/Mute to silence it and ventilate. It returns to normal (steady green) once the CO has cleared. On a 62 Series, a short press afterwards shows the peak CO level it recorded.
What color wires does a Safe-T-Alert have?
Red goes to +12 V on a fused circuit and black goes to ground.
Can I reset the end-of-life signal for good?
No. After 30 days of muting it can no longer be silenced, by design. Replace the alarm: our Safe-T-Alert replacement chart shows which current model fits your old one.
Where is the manual for my old Safe-T-Alert?
Look up its current replacement in the replacement chart, then use that series' manual above. The wiring (red to +12 V, black to ground) is the same across the current range.
Every Safe-T-Alert alarm we sell 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.