The HD-503-2 Wired Heat Detector is a reliable fire safety device designed to detect temperature increases in the surrounding environment. Operating with a wide voltage range of DC 9V to 35V (and optional orders for DC 40V to 60V), this detector ensures efficient and stable performance in various settings. It features different standby current settings based on its wiring configuration: in a 2-wire setup, the current is ≤50 µA, while in a 4-wire setup, it can be ≤50 µA (relay normally open) or ≤16 mA (relay normally closed). In the event of a temperature rise to 57°C, the device will trigger an alarm with an indication via a red LED. The alarm current for a 2-wire system is 20-25 mA at 12V and 40-50 mA at 24V, while for a 4-wire system, it is ≤40 mA (relay NO) and ≤20 mA (relay NC). Resetting the detector can be done automatically or by powering it off. The device is capable of operating in both 2-wire and 4-wire systems, with a remote LED indicator for 2-wire systems and a relay output for 4-wire systems. The relay output has a contact rating of 0.5A at DC 28V for 4-wire systems. Built in compliance with EN54-5:2008 fire safety standards and CE certified, the HD-503-2 ensures high standards of reliability and safety. It has compact dimensions of Ø100.7 mm in diameter and 50.7 mm in height, making it easy to install in various locations.
| Feature | Specification |
|---|---|
| Model | HD-503-2 |
| Type | Wired Heat Detector |
| Operating Voltage | DC 9V ~ 35V (Optional: DC 40-60V) |
| Standby Current (2-Wire) | ≤50 µA |
| Standby Current (4-Wire) | ≤50 µA (NO), ≤16 mA (NC) |
| Alarm Current (2-Wire) | 20 |
| Alarm Current (4-Wire) | ≤40 mA (NO), ≤20 mA (NC) |
| Alarm Indication | Red LED |
| Reset | Power off or auto reset |
| Alarm Output | Remote LED for 2-wire; relay output for 4-wire |
| Contact Rating | 0.5A @ DC 28V (4-wire) |
| Alarm Temperature | 57°C |
| Standard | EN54-5:2008 |
| Certificate | CE |
| Dimensions | Ø100.7 mm x 50.7 mm |


















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