1. Introduction
The Ademco Honeywell 5816 is a wireless two-zone transmitter designed for integration with compatible security systems. This device provides reliable security monitoring for doors and windows by detecting their open or closed status. It features a built-in magnetic reed switch and also supports an external wired closed-circuit contact loop, offering versatile installation options.
2. Product Features
- Wireless two-zone operation for flexible monitoring.
- Integrated magnetic reed switch for standard door/window contact.
- Support for an external wired closed-circuit contact loop (Loop 4).
- Includes a long-life CR123 Lithium Ion battery.
- Tamper detection for enhanced security.
3. Package Contents
Verify that all items are present before beginning installation:
- Ademco Honeywell 5816 Wireless Transmitter unit
- Mounting plate
- Magnet (typically 5899 magnet)
- Magnet spacer
- Mounting screws
- Double-sided adhesive tape
- CR123 Lithium Ion battery
4. Setup and Installation
Proper installation ensures optimal performance and reliable security. Refer to your security system's control panel manual for specific programming instructions.
4.1. Battery Installation
- Open the transmitter casing by gently pressing the tab on the bottom and lifting the cover.
- Insert the supplied CR123 Lithium Ion battery, observing the correct polarity (+/-).
- Close the cover securely.
4.2. Mounting the Transmitter and Magnet
The transmitter and magnet should be mounted on the door/window frame and the moving part (door/window) respectively, ensuring they are aligned and within approximately 1 inch (2.5 cm) of each other when the door/window is closed.

Image 1: Front view of the Ademco Honeywell 5816 Wireless Transmitter. This image displays the compact, rectangular design of the transmitter unit, typically mounted on a door or window frame.
- Choose a mounting location on the door or window frame where the transmitter will not interfere with operation and is protected from damage.
- Mount the transmitter using the provided screws or double-sided adhesive tape. Ensure the mounting plate is secured first, then attach the transmitter.
- Mount the magnet on the corresponding moving part (door or window) directly opposite the reed switch marking on the transmitter. Use the magnet spacer if necessary to achieve proper alignment and gap.
- Test the alignment by opening and closing the door/window. The security system should register the change in status.
4.3. Wiring an External Contact (Optional)
The 5816 transmitter supports an external wired closed-circuit contact loop (Loop 4). This allows for monitoring of a separate device or a different type of contact.
- Connect the external contact wires to the designated terminals inside the transmitter.
- Ensure connections are secure and properly insulated.
- Program the external loop (Loop 4) into your security system's control panel as per its instructions.
5. Operating Instructions
The Ademco Honeywell 5816 operates by wirelessly transmitting signals to your security system's control panel when a change in its contact status occurs.
- Normal Operation: When the door or window is closed, the magnet is in close proximity to the transmitter's reed switch, indicating a closed state.
- Open State: When the door or window is opened, the magnet moves away from the transmitter, causing the reed switch to open. The transmitter then sends an "open" signal to the control panel.
- External Contact: If an external contact is wired, it will transmit signals based on its own open/closed status, independent of the internal reed switch.
- Tamper Detection: If the transmitter's cover is removed, a tamper signal will be sent to the control panel, indicating unauthorized access to the device.
The control panel interprets these signals and responds according to its programming (e.g., sounding an alarm, sending notifications).
6. Maintenance
6.1. Battery Replacement
The 5816 transmitter uses one CR123 Lithium Ion battery, which typically has a life of approximately 5 years. Your security system will usually provide a low battery warning when replacement is needed.
- Disarm your security system to prevent false alarms during battery replacement.
- Gently press the tab on the bottom of the transmitter and remove the front cover. This action may trigger a tamper alert on your control panel, which can be cleared after replacement.
- Carefully remove the old CR123 battery.
- Insert a new CR123 Lithium Ion battery, ensuring correct polarity.
- Replace the front cover, ensuring it snaps securely into place.
- Verify that the transmitter is communicating with the control panel by testing the door/window.
6.2. Cleaning
Clean the exterior of the transmitter and magnet periodically with a soft, dry cloth. Avoid using abrasive cleaners or solvents, as these can damage the casing.
7. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Transmitter not responding / No signal | Dead or low battery; Magnet misalignment; Out of range; Programming issue. | Replace battery; Adjust magnet position (within 1 inch); Verify transmitter is within range of control panel; Check control panel programming. |
| False alarms / Intermittent signals | Loose wiring (for external contact); Magnet too far from transmitter; Environmental interference. | Check external contact wiring; Realign magnet; Ensure no large metal objects are interfering; Consult control panel manual. |
| Low battery warning persists after replacement | Incorrect battery type; Battery not fully seated; System not reset. | Ensure correct CR123 Lithium Ion battery is used; Re-seat battery; Refer to control panel manual for clearing low battery signals. |
If issues persist, consult your security system's control panel manual or contact a qualified security technician.
8. Specifications
| Model Number | 5816 |
| Dimensions (H x W x D) | 3-1/16'' x 1-9/16'' x 1-3/16'' (approx. 7.78 cm x 3.97 cm x 3.02 cm) |
| Weight | 12.6 ounces (approx. 357 grams) |
| Power Source | Battery Powered |
| Battery Type | 1 x CR123 Lithium Ion battery |
| Nominal Voltage | 3 Volts (DC) |
| Average Battery Life | Approximately 5 years |
| Special Features | Magnetic contact, Wireless, Tamper detection |
| Compatible Devices | Honeywell Home 5800 Series devices, 5899 magnet |
| Wireless Range | Up to 200 feet (approx. 61 meters) indoors; over 1 mile (approx. 1.6 km) outdoors (line of sight) |
| Water Resistance Level | Not Water Resistant |
9. Warranty and Support
Specific warranty information for the Ademco Honeywell 5816 Wireless Transmitter is typically provided at the point of purchase or through your security system installer. Please retain your proof of purchase for warranty claims.
For technical support, programming assistance, or troubleshooting beyond the scope of this manual, please contact your security system provider or a certified Honeywell/Ademco dealer.
10. Additional Resources
For further details on integrating this transmitter with your specific security system, refer to the installation and programming guides for your Honeywell or Ademco control panel.
No official product videos are available for inclusion in this manual.





