How To Reset A Hardwired Smoke Detector

A hardwired smoke detector can be reset by pressing and holding the reset or test button for 15 seconds. If that fails to stop the alarm from beeping, replace the backup battery with a new one.

State laws in the US mandate installation of smoke alarms in all residential areas. While many people use battery smoke alarms, detectors that are wired directly into the home’s electrical system are becoming more common, but they are reset differently to battery-operated models.

This article explains hardwired smoke detectors, how they work, and what possible ways they can malfunction. We obviously also explain how to reset your smoke detector!

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Types of Hardwired Smoke Detectors

Smoke detectors have built-in sensors that activate the alarm to go off when they detect smoke.

There are two main types of smoke detectors:

1. Ionization Alarm

These detectors are made by placing a radioactive material between two electrostatic plates. The plates release high-energy charged particles, and the resultant ionized particles move between the plates.

In case of fire breakouts, smoke molecules enter the detector and disrupt the otherwise continuous flow of ions. This activates the alarm.

2. Photoelectric Alarms

Photoelectric fire alarms are suitable for smoldering fires.

They are constructed with a light source that normally points away from the chamber that has sensors. If smoke enters the detector, it deflects the light toward the sensors, which triggers the alarm.

For optimal protection, it is generally recommended to install both ionization and photoelectric detectors.

Based on the power source, smoke alarms have two categories – battery-powered and hardwired. While the battery-powered models run exclusively on batteries, hard-wired detectors are connected to the home’s power supply and only use batteries in the event of a power outage.

How To Reset Hardwired Smoke Detectors

Here’s how to reset a hardwired smoke detector:

  • Turn off the power at the circuit breaker.
  • Switch the smoke detector off, and remove it from the mounting bracket by unplugging the pins or connectors located at the back.
  • Take out the backup battery.
  • Press the reset or test button for 10 to 15 seconds until you hear a chirp for a few seconds – Refer to your user manual for the location of the reset button on your specific model.
  • Reinstall the detector after replacing the battery, and reconnect the power supply.

The unit should chirp once when reconnected to the power supply.

Note that once the alarm is set off in a hardwired smoke detector (due to actual smoke breakout instead of an error), it tends to automatically reset itself.

Identifying the cause of beeping (such as steam from the kitchen), and resolving it (for example, by opening windows and doors for adequate ventilation) is generally enough to turn off the alarm.

If your smoke alarm continues to beep and you can’t figure out why, Plentiful Air has a complete troubleshooting guide available here.

Always remember – check for an actual fire, or smoke, before resetting your smoke detector. It may just be doing it’s job by beeping and you should take appropriate action in the event of a fire.

5 Reasons You Should Reset Your Hardwired Smoke Detector

Smoke detectors are usually reset every time the alarm goes off. You also need to reset the detectors if they make unusual chirping or beeping sounds (error conditions) or start acting up.

Here are all the possible reasons why your detector can be malfunctioning – once you have fixed your problem you will then need to reset your device:

1. Battery Needs Replacing

Even though hardwired smoke detectors are powered by the main electrical supply of the house, they do have a backup battery that prevents interruption in device operation in the event of a power outage.

If the battery is low or about to die, the detector starts making chirping sounds as an indicator.

Changing the battery and resetting the device afterward will solve the problem.

Note that as per the guidelines of the National Fire Protection Association (NFPA), batteries in smoke detectors should be replaced every six months. But, if you notice your battery doesn’t last this long and dies more frequently, you need to check for any wiring issues instead of just replacing the battery.

This problem usually arises when the hardwired detector is running exclusively on battery due to a tripped circuit breaker or loose wire nut. Due to potential electrical accidents, you should always get a professional electrician to look into and fix this problem.

Remember that some smoke detectors come with a lifetime backup battery that cannot be replaced. Once the battery dies out, the device will keep beeping, which won’t be resolved by resetting the system.

2. Loose Battery

If your detector continues to chirp even after replacing the battery, it can be because the battery is not sitting in place properly.

Here’s what to do:

  • Remove and reconnect the battery, and make sure it is secured in place.
  • If the detector has a front-load battery, check if the battery compartment door is closed.
  • Reset the detector.

To ensure optimal performance, it is important to always buy the original, recommended type of battery with no more than 4 to 5 years from the expiry date.

3. Dust Buildup In Detector

Smoke detectors are installed in ceilings and walls in an open area and are prone to dust buildup. When the dust collects in the sensing chamber, it can cause the detector to chirp.

These dust particles and airborne debris can also trigger the alarm, so if your device goes off randomly, it is likely happening due to contaminant accumulation.

Cleaning your smoke alarm regularly with a powerful vacuum cleaner will usually prevent this problem. You will also need to dust the outside with a dry microfiber cloth.

Twice a month (or more frequently in case of dust storms or poor air quality index), manually clean the air vents and inner side of the detector with a soft bristle brush.

Since maintenance is particularly difficult with hardwired smoke detectors, we recommend running a powerful HEPA air purifier in the room to stop dust and debris collection (although this is certainly an added cost that is not always feasible).

Plentiful Air has more information on air purifiers that remove dust available here.

Instead, you could consider buying a high-end smoke detector with an anti-dust screen. These filtration screens are made of conductive fabric that prevents airborne pollutants and dust particles from passing into the device (while not repelling smoke particles).

If the alarm keeps going off despite regular maintenance, you should next check for insects caught inside the sensor chamber. You can also look for units with anti-insect screens that prevent bugs, ants, mosquitoes, etc., from crawling into the detector.

4. Unusual Temperature Or Excessive Humidity

Unusual indoor temperature (hot or cold) or excessive humidity can cause smoke detectors to beep.

Check if any HVAC device or open window is within three feet of the alarm. An extreme temperature or excess airflow from appliances or open windows can interfere with the detector, setting off the alarm.

Similarly, placing the detector near a washroom or kitchen area can expose it to excess condensation, humidity, and steam, which again triggers the alarm.

As a rule of thumb, always make sure that smoke detectors are placed in moderately humid or dry areas with the optimal surrounding temperature, i.e., 40 to 95 degrees.

In case of naturally extreme weather conditions, placing dehumidifiers and suitable HVAC appliances inside the house is essential.

5. Damage

Exposure to chemicals, fire, grease, and impact, can damage smoker detectors.

Once damaged a faulty unit starts acting up, which you can usually tell by error sounds (beeping and .chirping). Severe damage can also trigger the alarm.

Unfortunately, you will have to call customer service to inspect and fix this issue. Afterward, clean the device thoroughly, install it back in place, and reset it before using it again.

Although, sometimes it is cheaper to just buy a replacement.

Frequently Asked Questions

Why Is My Smoke Alarm Chirping If It Is Hardwired?

Smoke detectors generally chirp to indicate a low or dead battery. Hardwired smoke detectors have a 9V backup battery (used in case of an electricity outage), and the detector might chirp if the battery is dead or about to die.

Replacing the battery will resolve the issue. Ideally, batteries should be changed twice a year.

Other rare but possible factors that are sometimes indicated by chirping sounds are dust buildup inside the detector or any potential malfunction.

Can I Disconnect A Hardwired Smoke Detector Without Turning Off the Power?

Unplugging a hardwired smoke detector without turning off the main power supply is a safety hazard and should be avoided. Turn the power supply off, and then locate and remove the pin or connector on the back of the detector to unplug it.

Russell Singleton

Russell holds a Bachelor of Science (Environmental and Marine Geoscience) with Class I Honors. He is currently completing his doctorate in science and is passionate about all earth processes, especially isotope geochemistry and paleohydrology.

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