Apollo XP95 Addressable Heat Detector, Fixed 55°C (A2S) 55000-400APO

Introduction to the Apollo XP95 Addressable Heat Detector (55000-400APO)

Apollo 55000-400APO — XP95 addressable fixed-temperature heat detector (A2S)is a loop-powered, addressable heat detector engineered for environments where smoke detection is impractical or prone to nuisance alarms. With a fixed alarm threshold of approximately 55°C (A2S) and an industry-standard XP95/Discovery protocol interface, the detector offers reliable thermal sensing using a single NTC thermistor and continuous sampling. The unit’s low-airflow polycarbonate housing, integrated red LED, remote indicator terminals and low quiescent current make it a strong choice for commercial and industrial applications such as kitchens, car parks, warehouses and plant rooms.

Key features at a glance

• Fixed-temperature classification:≈55°C (A2S) alarm point for rapid response to sustained heat rises.
• Addressable protocol:XP95 / Discovery loop-powered operation (17–28 V DC), enabling individual device identification and easier system fault finding.
• Reliable sensing:Single NTC thermistor with continuous sampling for steady thermal measurement.
• Construction:Low-airflow white polycarbonate housing (self-extinguishing) with stainless / nickel-plated terminals for durability.
• Visual indicators:Integral red alarm LED and remote indicator terminals (+R / −R) to support remote annunciation.
• Low power draw:Quiescent current optimised for addressable loops.

Detailed specifications and benefits

The Apollo XP95 55000-400APO packs technical design choices that prioritise reliability and compatibility with modern fire alarm systems. Below are the key specification highlights and what they mean in practical terms.

• Part number:55000-400APO.
• Classification:≈55°C (A2S fixed-temperature).
• Sensor:Single NTC thermistor — continuous sampling ensures stable temperature readings and predictable alarm behaviour.
• Protocol:XP95 / Discovery addressable — enables individual addressing and integration with compatible control panels.
• Supply voltage:17–28 V DC; protocol modulation 5–9 V peak-to-peak.
• Quiescent current:≈250–300 µA typical at 24 V; low standby drain is well-suited to long addressable loops.
• Alarm current (LED):≈2–4 mA when the LED is illuminated.
• Connections:L1 & L2 loop in/out; +R / −R remote LED terminals.
• Approvals:EN54-5 and other approvals (LPCB/CPR reported by manufacturer); confirm region-specific certificates from the datasheet.

• Dimensions:Ø100 × 42 mm (detector only); approximately 50 mm overall when on a base.
• Weight:≈105 g (detector only); ≈157 g with base.
• Operating temperature:−20°C to +70°C.
• Storage temperature:−30°C to +80°C.
• IP rating:Reported variably as IP43 / IP53 — check the datasheet and installation requirements for the exact protection level needed.
• Housing:Low-airflow white polycarbonate, self-extinguishing; terminals are stainless / nickel-plated for corrosion resistance.

• Reduced nuisance alarms:Heat detection avoids false alarms in dusty, oily or smoky-but-safe environments where optical smoke detectors would trigger unnecessarily.
• Addressable advantages:Individual addressing simplifies commissioning, diagnostics and targeted maintenance, reducing downtime and service costs.
• Robust installation:Low-airflow design and durable materials improve performance in high air-movement areas and harsh conditions.
• Visual and remote indication:The integral LED plus remote terminals make local and remote alarm indication straightforward for building management.
• Energy efficient:Low quiescent current enables longer loops and supports power budgeting on complex systems.

Use cases and scenarios where the detector excels

The Apollo XP95 55°C heat detector is purpose-built for areas where smoke detection is unsuitable or unreliable. Typical applications include:

• Commercial kitchens:Cooking fumes, steam and grease can cause frequent false alarms for smoke detectors. A fixed-temperature heat detector responds to persistent heat rises rather than transient particulates.
• Car parks:Vehicle emissions and dust make optical detectors prone to nuisance alarms. Heat detectors identify real thermal hazards such as engine fires.
• Industrial warehouses and production areas:Dust, lint and airborne contaminants in manufacturing sites reduce smoke detector effectiveness; heat detectors offer a reliable alternative.
• Plant rooms and boiler houses:Areas with high airflow near fans or ventilation where smoke sensors may underperform — a heat detector responds predictably to dangerous temperature increases.
• Dirty or oily environments:Locations with oil mist, soot or heavy dust that would coat smoke-sensing optics benefit from a fixed-temperature heat approach.

Comparisons with similar products and detection approaches

Choosing the right detector means balancing sensitivity, environment and system type. Below are practical comparisons to help specify correctly.

• Addressable units like the XP95 provide device-level identification, fault diagnostics and automatic polling—reducing maintenance time. Conventional heat detectors are simpler and cheaper but require zoned wiring and provide less diagnostic detail.

• A fixed-temperature detector alarms when ambient temperature reaches a set point (≈55°C). Rate-of-rise detectors trigger on rapid temperature increases, which can detect fast-developing fires sooner but are more susceptible to false alarms from sudden environmental changes (e.g., doors opening near heaters).
• Combination solutions (fixed + rate-of-rise) exist for faster detection in some scenarios; however, a 55°C fixed-temperature detector remains a reliable choice where sustained heat is the primary risk.

• Smoke detectors are typically more sensitive to early-stage smouldering fires and provide faster alerts in enclosed, clean-air spaces. Heat detectors are preferable in dirty, smoky or high-airflow environments where smoke sensors would nuisance alarm or be unreliable.
• Where both early warning and robustness are required, hybrid systems (smoke detectors in cleaner areas and heat detectors in harsh zones) provide comprehensive coverage.

Important installation notes and certification considerations

• Base compatibility:The detector mounts on a compatible XP95 base (sold separately) — ensure you specify the correct base for your installation.
• IP rating and environment:IP43 / IP53 is reported variably — confirm the required protection level from the manufacturer’s datasheet when deploying in exposed or washdown environments.
• Approvals:EN54-5 certification is listed; other approvals such as LPCB/CPR may apply depending on region. Check the datasheet for certificates required by your authority having jurisdiction.
• Competent installation:Installation and commissioning must be performed by a competent person in accordance with the manufacturer’s instructions and local fire regulations. Always isolate circuit power before wiring.

Conclusion — why choose the Apollo 55000-400APO XP95 Heat Detector?

The Apollo XP95 55°C (A2S) addressable heat detector is a purpose-built solution for demanding environments where smoke detection is impractical. Its addressable XP95/Discovery protocol support, low power consumption, clear visual indication and robust low-airflow housing make it an efficient, reliable choice for kitchens, car parks, warehouses, plant rooms and similar locations. With EN54-5 certification and proven installer preference for its integration and performance, the 55000-400APO offers an effective balance of reliability, maintainability and cost-efficiency.

Practical note:The detector is supplied without a base (base sold separately). Verify required IP protection and approvals for your region prior to specifying, and consult the Apollo datasheet and installation manual for full technical and compliance details.