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DIY Mini Smoke Alarm with Long Life Battery KD-125C

KD-125C Smoke Alarm is a photoelectric smoke alarm with low power consumption. Internal precise analog circuit and digital circuit make the detection work more stable and reliable. The product has a small size and uses large-capacity battery which can provide service life of 5 years.
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  • KD-125C


  • 8531100000

KD-125C  Smoke Alarm User Manual



1. Brief introduction

KD-125C Smoke Alarm is a photoelectric smoke alarm with low power consumption. Internal precise analog circuit and digital circuit make the detection work more stable and reliable. The product has a small size and uses large-capacity battery which can provide service life of 5 years.

2. Product characteristics

Photoelectric smoke detection

High sensitivity

Precise analog circuit and digital circuit

Low power consumption

Small size

Battery service life of 5 years

3. Technical parameters

Technical parameters

Smoke detection



Low battery warning



Alarm current

Quiescent current



Status display

Standby condition

LED (red) flashes once about every 344 seconds, no alarm sound

Alarm condition or test

LED (red) flashes and continuous alarm is given

Low sensitivity detection (silence mode)

LED (red) flashes every 10 seconds, no alarm sound, automatically cancel low sensitivity detection about 9 minutes later

Alarm memory

LED (green) flashes 3 times about every 43 seconds, and that stops 24 hours later. The first time you press test/hush button after alarm is made, the detector will hint by special alarm mode.

Low battery warning

The product beeps about every 43 seconds

Alarm loudness


Working temperature


Ambient humidity

≤95%RH  (no condensation)

4. Appearance and dimensions(Figure 1)

KD-125 A

(Figure 1)

5. Installation

5.1 Functional diagram (Figure 2)

(Figure 2)

5.2 Installation Instructions

a. Hold the mounting plate against the selected installation position on the ceiling, and mark the center of the holes with a pencil. Drill a hole through the pencil marks and use the enclosed screws and anchors to secure the mounting plate. (See Figure 3)

b. Install the batteries according to Figure 3, making sure the polarity matches the markings. If the batteries are installed correctly, the red pin will drop automatically.

c. Insert the hook of the product into the slot of mounting plate. Then turn the alarm clockwise until it snaps into place.

  (Figure 3)

Note: If you can’t rotate the alarm after insert the hook into the slot, please check if the battery is installed correctly.

5.3 Replacing battery

a. When low battery warning is made (please refer to section 6. Function), please replace the batteries immediately, as shown below.


Turn the alarm anticlockwise and         Take the batteries out and install

remove it from the mounting plate.        the new ones according to 5.2 b.

b. Use battery type: LR03/AAA.

c. Whenever the batteries are replaced, test the operation of the alarm by pressing the TEST button. If beeps are made which means the product works properly, install the alarm to the mounting plate as shown in Figure 3.

5.4 Recommended Locations for Smoke Alarms and Locations to Avoid

a. Recommended Locations for Smoke Alarms

Install at least one smoke alarm in every bedroom

If you install the smoke alarm in a passageway whose width is less than 3m, install it in the middle and install one unit every 12m.

At least 1.5m from fluorescent lamp or neon lamp. (In case of electronic interference).

At least 3m from the bathroom.

At least 6m from the kitchen or stove.

At least 30cm from the lamps.

Locate the smoke alarm in the middle of the room. If you can’t, install it at least 1m from the wall.

If you install the smoke alarm on sloped or peaked ceiling, the installation position shall be at least 90cm from the highest point.

b. Locations to Avoid

In the garage. Products of combustion are present when you start your automobile.

Near fresh air vents, fans, air conditioner or other drafty areas.

In an area where insects often appears.

In an area where the temperature may fall below 0℃ or rise above 40℃.

In humid areas. Bathroom. Kitchen.

6. Function


Press the TEST button and the product will enter alarm mode. It will make beeps that are louder than 86dB. The alarm indicator (red) will flash.

Standby condition

In standby condition, the smoke alarm detects every 10 seconds. The alarm indicator flashes every 344 seconds to indicate that the smoke alarm is operating properly. When it senses products of combustion, the alarm sounds. And the alarm indicator (red) flashes at the same time, until the air is clear.

Silence mode (Low sensitivity)

When it’s in alarm condition, press the TEST/HUSH button and the product will enter silence mode. The alarm indicator flashes every 9 seconds and no audible sound will be heard, unless smoke becomes denser. That will last for about 9 minutes. Pressing the TEST/HUSH button again will end the silence mode.

Low battery warning

When the battery voltage is too low, the product will make short beeps every 43 seconds to warn the user, until the battery voltage comply with the working voltage of the smoke alarm.

Alarm history

When the alarm indicator (green) flashes 3 times every 43 seconds, that means alarm has been made before. Please check if there is fire risk in detecting area. This indication will end 24 hours later.

Smoke chamber degeneration warning

The working environment and time will cause the degeneration of smoke chamber. When the product makes 3 short beeps every 43 seconds, it indicates end-of-unit-life. You should replace the smoke alarm with a new one.

7. Maintenance

7.1 Test the smoke alarm every week by pressing the test button.

7.2 Clean the smoke alarm with dry cloth. Never use water, cleaners or solvents to clean since they may damage the unit. Prevent foreign body from entering the unit.

7.3 If the smoke alarm is not working properly, don’t disassemble the unit yourself. Please seek the service of the professionals.

8. Points for Abandoned Products

The packing material is renewable, so please do your best to recycle it.


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