Bosch D253 is a two-wire 24 VDC heat detector base

The D253 is a two-wire 24 VDC heat detector base with a latching steady-on alarm LED. It accepts Bosch D254 and D255 heat detector heads.

D253 Two-wire Detector Base (24 VDC)

• 24 VDC, two-wire circuit compatibility

• Latching LED

• Low-profile six-inch diameter base accepts interchangeable detector heads

• Easy head removal for cleaning and servicing

• Standard screw terminal connectionsCertifications and Approvals

Installation/Configuration Notes
Compatible Products
The following products are compatible with the D253 two-wire Detector Base:

 * The D253 requires use of a D125B Powered Loop Interface Module and a separate UL Listed 24 VDC power supply. Use a D130 Relay Module to reset the 24 VDC detectors with a Reset Sensor command from the control panel.
Note Bosch makes no claims either written, oral, or implied that the D253 works with any control panel other than those listed above.

Mounting
The D253 base fits on standard three-inch octagonal and four‑inch square and octagonal back boxes.

Wiring
Refer to the installation instructions (P/N: 42885) for detailed wiring requirements.

Parts Included

Technical Specifications