Frequently Asked Questions
Smoke Alarms Carbon Monoxide Alarms For 120 Volt Wired-In Carbon Monoxide Alarms

  Smoke Alarms
QUESTION:
Why does my smoke alarm "chirp" approximately once every minute?
ANSWER:

The smoke alarm chirps to indicate a "low battery" condition, meaning the battery needs to be replaced. Battery powered smoke alarms will chirp a minimum of 30 days before the battery completely loses power.

AC powered smoke alarms with battery backup will chirp indefinitely assuming AC power is present; if battery power is low, or battery is removed; until a fresh battery is installed. Approved replacement batteries are listed on the back of each smoke alarm and in the user's manual.

Certain model smoke alarms with a silence button (designed to silence the alarm during a nuisance alarm) may chirp to indicate the smoke alarm is in the silence mode. The chirp will stop after approximately 8 minutes and the smoke alarm will return to its normal operation.


QUESTION:
What does it mean when the red light flashes approximately once every minute?
ANSWER:
The flashing red light gives a visual indication that the smoke alarm is functioning properly. It also indicates a working battery is connected to the smoke alarm.
QUESTION:
What does the continuous green light indicate?
ANSWER:
It indicates that AC power is operating the smoke alarm.
QUESTION:
Why must I disconnect AC power before changing batteries
ANSWER:
In case the electrician has miswired the AC voltages, a shock hazard might exist. By disconnecting the AC power, it will ensure that the battery can be changed safely.
QUESTION:
The green light on my smoke alarm has gone out, what does this mean?
ANSWER:
The AC power has been interrupted. Check the circuit breaker and AC wiring to correct the problem.
QUESTION:
How can I tell which smoke alarm in a multi-station (interconnected) installation initiated the alarm?
ANSWER:
While the unit is alarming, the smoke alarm which initiated the alarm, either by test button or sensing smoke, will flash the red LED light approximately once per second. The red LED light on the other non-initiated interconnected smoke alarms will not be lit but will sound the alarm.
QUESTION:
What is the total number of smoke alarms or devices I can interconnect?
ANSWER:

Twenty-four. The NFPA 72 standard states the interconnect limit is 12 smoke alarms and up to 6 other alarms (heat or carbon monoxide) for a total of 18 alarms. With 18 alarms interconnected, up to additional 6 relay modules may be interconnected (for a maximum of 24 devices).
If battery backup alarms and non-battery backup alarms and accessories are mixed in an interconnect system, all devices without battery backup WILL NOT operate during an AC power failure.

CAUTION: USI alarms and accessories should only be interconnected with other USI alarms and accessories. Connecting devices from another manufacturer to USI devices may result in nuisance alarms, failure to alarm, or damage to one or all of the devices in the interconnect system.

All interconnected USI alarms should be powered by the same fuse or circuit breaker. Smoke alarms shall not receive their power from a circuit that is protected by a ground fault circuit interrupter. Improper connection will result in damage to the alarm, failure to operate, or a shock hazard.

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Carbon Monoxide Alarms
QUESTION:
What levels (ppm) of carbon monoxide cause an alarm?
ANSWER:

Carbon monoxide alarms are designed to alarm before the average healthy adult feels symptoms.

Since you cannot see or smell CO, never assume it's not present.

Underwriters Laboratories Inc. Standard UL2034 requires residential CO alarms to sound when exposure times and exposure levels of CO in the chart below. CO alarm levels are measured in parts per million (ppm) of CO over time (in minutes). The UL2034 Required Alarm Points are:

  • If the Alarm is exposed to 400 ppm of CO, it must alarm between 4 and 15 minutes.
  • If the Alarm is exposed to 150 ppm of CO, it must alarm between 10 and 50 minutes.
  • If the Alarm is exposed to 70 ppm of CO, it must alarm between 60 and 240 minutes.

The alarm is designed not to alarm when exposed to a constant level of 30 ppm for a period of 30 days.


QUESTION:
Is carbon monoxide heavier than air?
ANSWER:
Carbon monoxide is not heavier than air. A carbon monoxide alarm should be installed in a location where the alarm will stay clean, and out of the way of children or pets. Refer to the user's manual for specific installation requirements.
QUESTION:
What does "move to fresh air" mean?
ANSWER:

The phrase "move to fresh air" is printed on the cover as reminder to move everyone to a well-ventilated area with fresh air when the CO alarm sounds.

Note: Do not unplug or move the CO alarm. When the CO alarm sounds, make sure that everyone in the home/building is evacuated to an area with fresh air.


QUESTION:
Why didn't the fire department, gas company or emergency responder locate the source of CO after my alarm sounded?
ANSWER:

If your carbon monoxide alarm went off, it detected a dangerous level of CO. Some reasons why a responder may not find CO during an investigation:

  • CO levels dissipated in fresh air. If windows and doors were opened before the first responder arrived, the same concentration of CO gas may no longer be present. Be safe first and vent dangerous carbon monoxide gas to the outside. The responder can try to recreate the conditions. If your CO alarm is a model containing a digital display, there is a "peak level" button which will display the highest level of CO detected by the alarm since the alarm was reset.
  • The alarm may have been caused by an on-again, off-again problem. CO alarms measure gas exposure over time, so the exact conditions that caused an alarm may be difficult to duplicate during a CO investigation.
QUESTION:
Will carbon monoxide alarms detect explosive gas leaks?
ANSWER:
No, not unless it is specifically marked as an explosive gas alarm. Our CO alarms are single function and react to carbon monoxide only. To detect explosive gas, you need an explosive gas alarm. Different kinds of explosive gas can be detected and it is recommended that any home that utilizes natural or propane gas have at least one explosive gas leak alarm.
QUESTION:
Can you reset a plug-in CO alarm with the test/silence button?
ANSWER:
No, the test/silence button only tests or silences the CO alarm. To reset the alarm, the alarm needs fresh air and time to burn the contamination off the sensor. Push and hold the silence button for 5 seconds to silence the alarm while contamination is being burned off the sensor. You may need to do this a number of times to give the carbon monoxide alarm enough time to reset.
QUESTION:
Can I test my CO alarm any way besides pressing the test button?
ANSWER:
No, pressing the test/silence button is the only proper way to test the CO alarm. NEVER use vehicle exhaust or some other CO source. Exhaust causes permanent damage and voids the warranty.
QUESTION:
Where should I install my carbon monoxide alarms?
ANSWER:
It is very important to install a carbon monoxide alarm outside each separate sleeping area, and for maximum protection, install one in every bedroom. Many states now require installation of a carbon monoxide alarm inside each bedroom. For added protection, placement of an additional carbon monoxide alarm at least 15-20 feet away from the furnace or fuel burning heat sources is recommended. Install carbon monoxide alarms a minimum of 10 feet from sources of humidity like bathrooms and showers. In multiple-story dwellings, install one carbon monoxide alarm on every level. If you have a basement, install a carbon monoxide alarm at the top of the basement stairs, and in each separate sleeping area.
QUESTION:
What areas should I avoid installation of a carbon monoxide alarm?
ANSWER:
Do not install carbon monoxide alarms in garages, kitchens, furnace rooms, or in any extremely dusty, dirty, humid, or greasy areas. Do not install alarms in direct sunlight, or areas subjected to temperature extremes. These areas include unconditioned crawl spaces, unfinished attics, un-insulated or poorly insulated ceilings, and porches. Carbon monoxide alarms should not be installed in outlets covered by curtains, heavy furniture or other obstructions. Do not install in turbulent air-near ceiling fans, heat vents, air conditioners, fresh air returns, or open windows. Blowing air may prevent carbon monoxide from reaching the CO sensors.
QUESTION:
Can I interconnect carbon monoxide alarms with smoke alarms?
ANSWER:
Generally, yes. Refer to the specific information contained in your user's manual to verify the alarms are compatible.
QUESTION:
What are some common sources of carbon monoxide (CO)?
ANSWER:

Carbon Monoxide is a colorless, odorless, tasteless gas that's produced during incomplete combustion of any fuel like natural gas, charcoal, gasoline, kerosene, wood, gas, oil or coal. Common sources include:

  • A vehicle running in an attached garage
  • Furnace
  • Clothes dryer
  • Range
  • Oven
  • Stove
  • Fireplace
  • Water heater
  • Space heater
  • Portable generator
  • Charcoal grill

When there is enough fresh air in your home to allow for complete combustion and these appliances are vented and work properly, in normal operating conditions, the trace amounts of CO produced by these sources are not typically dangerous. However, there are common conditions that can cause CO levels to rise quickly:

  • Appliance malfunction, i.e. the heat exchanger on your furnace cracks
  • Vent, flue, or chimney is blocked by debris or even snow
  • Fireplace, wood burning stove, charcoal grill or other source of burning material that is not properly vented
  • Vehicle is left running in an attached garage and carbon monoxide seeps into the house
  • Several appliances running at the same time and competing for limited fresh air can be a cause of carbon monoxide buildup. This condition can result in incomplete combustion and produce CO, even if all appliances are in good working condition.

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For 120 Volt Wired-In Carbon Monoxide Alarms
QUESTION:
Why must I disconnect AC power before changing batteries?
ANSWER:
In case the electrician has mis-wired the AC voltages, a shock hazard might exist. By disconnecting the AC power, it will ensure that the battery can be changed safely.
QUESTION:
Why does my CO alarm "chirp" approximately once every minute?
ANSWER:

The CO alarm chirps to indicate a "low battery" condition, meaning the battery needs to be replaced. Battery powered CO alarms will chirp a minimum of 30 days before the battery completely loses power.

AC powered CO alarms with battery backup will chirp indefinitely (assuming AC power is present) if battery power is low (or battery is removed) until a fresh battery is installed. Approved replacement batteries are listed on the back of each CO alarm.


QUESTION:
What does it mean when the red light flashes approximately once every minute?
ANSWER:
On models containing a red light, the flashing red light gives a visual indication that the CO alarm is functioning properly. It also indicates a live battery is connected to the CO alarm.
QUESTION:
What does the continuous green light indicate?
ANSWER:
It indicates that AC power is operating the CO alarm.
QUESTION:
The green light on my CO alarm has gone out, what does this mean?
ANSWER:
The AC power has been interrupted - check the circuit breaker and AC wiring to correct the problem.
QUESTION:
How can I tell which alarm in a multi-station (interconnected) installation initiated the alarm?
ANSWER:
While the alarm is sounding, the CO alarm which initiated the alarm (either by test button or sensing CO) will flash the red LED light approximately once per second. The red LED light on the other non-initiated interconnected CO alarms will not be lit but will sound the alarm.
QUESTION:
What is the total number of CO alarms (or devices) I can interconnect?
ANSWER:

Six. The NFPA 72 interconnect limit is 12 smoke alarms and up to 6 other alarms, heat or carbon monoxide, for a total of 18 alarms. With 18 alarms interconnected, up to additional 6 relay modules may be interconnected (for a maximum of 24 devices).

If battery backup alarms and non-battery backup alarms and accessories are mixed in an interconnect system, all devices without battery backup WILL NOT operate during an AC power failure.

CAUTION: USI alarms and accessories should only be interconnected with other USI alarms and accessories. Connecting devices from another manufacturer to USI devices may result in nuisance alarms, failure to alarm, or damage to one or all of the devices in the interconnect system.

All interconnected USI alarms should be powered by the same fuse or circuit breaker. Aarms shall not receive their power from a circuit that is protected by a ground fault circuit interrupter. Improper connection will result in damage to the alarm, failure to operate, or a shock hazard.


QUESTION:
How often should I test my CO alarm?
ANSWER:
CO alarms should be tested weekly by depressing the push-to-test button until the alarm sounds.
QUESTION:
How long does a battery usually last in a CO alarm?
ANSWER:
9 Volt Carbon Zinc battery will last approximately 1 year.
9 Volt Alkaline battery will last approximately 3 years.
9 Volt Lithium battery will last approximately 10 years.
QUESTION:
How do I replace the battery in my CO alarm?
ANSWER:

AC with battery backup CO alarms - turn off AC power (green light should be off), twist CO alarm counterclockwise and remove from base. Disconnect battery and replace with new one. Reconnect CO alarm to base and turn power on.

DC - 9 Volt battery powered CO alarm - twist CO alarm counterclockwise and remove from base. Disconnect battery and replace with new one. Now reconnect CO alarm to base.

If a tamper pin is installed in the alarm, it will have to be removed in order to change the battery.


QUESTION:
What replacement batteries can I use?
ANSWER:
Refer to the user's manual or the label on the back of the alarm. Never use rechargeable batteries!
QUESTION:
Why can't I use rechargeable batteries?
ANSWER:

Rechargeable batteries are not approved for use in our alarms at this time. They do not always provide a consistent charge.

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