1 Purpose and Functions
The ACTii AC3849 flush-mount reed (magnetic) sensor is a professional security system component designed for discreet monitoring of the opening status of windows, doors, and other moving elements. Due to its design intended for internal profile installation, the device remains nearly invisible after mounting, which enhances the aesthetic finish and security level (more difficult access for unauthorized persons). The sensor works perfectly with frames made of plastic (PVC) and wood.
The device is characterized by its versatility due to the support of two output states (NO and NC), which allows for integration with almost any alarm control panel available on the market, including systems from brands like Satel, Elmes, Bosch, AVT, or Ropam.
Key features:
- ✔ Large working gap of up to 30mm, ensuring stable operation even with imprecise joinery fit
- ✔ Small dimensions allowing easy mounting in narrow profiles
- ✔ Robust ABS plastic housing resistant to mechanical damage
- ✔ Special stabilizing plastic teeth that allow for secure sensor seating in the hole without using glue
- ✔ NO (Normally Open) and NC (Normally Closed) output type implemented via a 3-wire system
- ✔ Aesthetic round masking flange to cover the edges of the drilled mounting hole
- ✔ Use of ruthenium (Ru) as a contact material, significantly extending the service life and reliability of the reed switch
Connection Information:
The device has three 25 cm long wires. The use of three cores allows for flexible system configuration:
- Brown wire: Common (COM)
- White wire (1): Output NO (Normally Open)
- White wire (2): Output NC (Normally Closed)
2 Technical Specification
| Gap (range) | 30 mm |
| Output type | NO / NC (switchable) |
| Maximum switching voltage | 200 V |
| Maximum switching current | 500 mA |
| Maximum continuous current | 1.5 A |
| Rated power | 10 VA |
| Contact material | Ru (Ruthenium) |
| Housing material | ABS plastic |
| Color | Brown |
| Operating temperature | -25°C to +85°C |
| Wire length | 25 cm |
| Product dimensions | 25 x 19 x 19 mm |
| Product weight | 18 g |
| Certificates | CE, RoHS |
3 Installation Manual
Hole preparation:
Flush mounting requires drilling two holes with a diameter of 19mm – one in the frame for the part with wires and another in the window or door sash for the magnet. Thanks to the flange, the hole does not have to be perfectly smooth, as its edges will be masked.
Sequence of steps:
- Mark the mounting locations so that when the window/door is closed, both elements are facing each other.
- Drill holes with a depth of at least 25mm.
- Pull the sensor wires through the hole in the frame to the inside of the profile or installation box.
- Push the sensor and magnet into the prepared holes. Plastic teeth on the housing will lock the elements, preventing them from sliding out.
- Check the correct operation using a universal meter before the final connection to the control panel.
4 Safety Rules and Maintenance
WARNING: Device designed for operation in low-voltage installations (alarm systems, DC control). Connection to the 230V AC mains risks death, permanent injury, and property damage.
- ● Do not exceed the maximum electrical parameters (voltage 200V, current 500mA).
- ● The sensor should not be mounted in places exposed to direct action of strong magnetic fields other than the dedicated kit magnet.
- ● In the case of mounting in steel doors, the operating range (gap) may significantly decrease – in such cases, it is recommended to use metal-isolating washers.
- ● The device does not require maintenance; however, it is recommended to test the alarm trigger every 6 months to check the correct operation of the contacts.