Mircom MIX-5251B Intelligent 135°F Fixed Temperature Heat Detector

The Mircom MIX-5251B Intelligent 135°F Fixed Temperature Heat Detector provides reliable thermal fire detection for compatible Mircom addressable fire alarm systems. It uses an electronic thermistor sensing circuit to detect temperatures reaching its fixed 135°F (57°C) alarm threshold.

Designed as part of Mircom’s MIX-200 Series intelligent low-profile sensors, the MIX-5251B combines addressable operation with a compact plug-in detector design. It is suitable for applications where thermal detection is preferred instead of, or in addition to, smoke detection.

Intelligent Fixed Temperature Detection

The Mircom MIX-5251B provides fixed-temperature thermal detection at 135°F (57°C). Unlike the MIX-5251RB, which incorporates both fixed-temperature and rate-of-rise detection, the MIX-5251B is specifically designed as a fixed-temperature heat detector.

When the detector senses the specified alarm temperature, the compatible addressable fire alarm system can identify the activated device by its assigned address. This provides precise point identification within the protected facility.

Low-Profile Addressable Design

The MIX-5251B features a low-profile plug-in configuration that provides a clean appearance while simplifying detector installation and replacement.

Mircom lists several compatible mounting options within the MIX-200 Series, including the B501 flangeless base, B210LP flanged base, B224RB relay base, and B224BI isolator base.

The detector and base configuration measures approximately 2-1/8 inches (53 mm) high and 6-1/8 inches (155 mm) in diameter.

Key Features

• Intelligent addressable thermal detector
• 135°F (57°C) fixed-temperature detection
• Low-profile plug-in design
• 15–32 VDC operating range
• Dual LED status indication
• Multiple compatible mounting-base options

Electrical Specifications

The Mircom MIX-5251B operates over a voltage range of 15 to 32 VDC peak. Mircom specifies a maximum average standby current of approximately 300 µA at 24 VDC for its thermal detectors. Maximum LED current is specified at 6.5 mA at 24 VDC.

These electrical characteristics allow the detector to operate directly on the compatible addressable signaling line circuit while maintaining relatively low standby power consumption.

Environmental Performance

The MIX-5251B is designed for indoor fire alarm applications. Mircom specifies an operating temperature range of -4°F to 100°F (-20°C to 38°C) for its 135°F heat detectors. The specified humidity range is 10% to 93% relative humidity, non-condensing.

These specifications make the detector suitable for many commercial and institutional environments where fixed-temperature heat detection is required.

LED Status Indication

The Mircom MIX-5251B incorporates LED indication to provide visible detector status. The indicators can assist technicians with identifying detector communication and alarm conditions during system testing, inspection, and maintenance.

The MIX-200 Series also supports the RA-100Z Remote LED Annunciator as an available accessory for applications requiring remote visual indication.

Commercial Fire Alarm Applications

The MIX-5251B can support thermal detection in offices, schools, commercial buildings, institutional properties, utility spaces, and other locations equipped with compatible Mircom addressable fire alarm systems.

Fixed-temperature heat detectors can be useful in areas where environmental conditions make smoke detection less appropriate. The detector should always be selected and located according to the approved fire alarm system design and applicable requirements.

System Compatibility

The Mircom MIX-5251B is a CLIP-protocol device and is listed in Mircom compatibility documentation for systems including the FX-2200. Mircom’s compatibility guide specifies a typical current draw of 300 µA for the MIX-5251B.

The MIX-5251B is a legacy detector. Mircom previously identified the MIX-5251AP as the recommended Advanced Protocol alternative for applications outside designated PRO-2000 projects and marine applications. Therefore, technicians should verify panel, protocol, and base compatibility before purchasing the MIX-5251B for an existing system.

Overall, the Mircom MIX-5251B Intelligent 135°F Fixed Temperature Heat Detector provides dependable addressable thermal detection with a compact low-profile design, 135°F alarm threshold, low standby current, and flexible mounting-base options for compatible Mircom fire alarm systems.

MIX-5251B Datasheet