The Opal NFXI-TFIX58 and NFXI-TFIX78 are fixed-temperature analogue addressable heat sensors designed for rapid and accurate detection. Utilising low-mass thermistors and advanced microprocessor technology, they deliver fast response times and precise linear temperature sensing. Their linear response enables operation across temperature ranges of 58°C (Class A1S) and 78°C (Class BS).

The Opal NFXI-TDIFF model incorporates the same thermistor and microprocessor technology but is configured to trigger an alarm when the temperature rises by more than 10°C per minute (typical) or exceeds 58°C (Response Class A1R). Through Notifier’s Opal protocol, this device can be software-configured as a fixed 58°C unit, a fixed 78°C unit, or a 58°C rate-of-rise sensor. For continued compatibility and certification, three dedicated versions remain available under separate part numbers.

All three heat sensors feature panel-controlled sensing elements via the Opal Protocol, allowing sensitivity thresholds to be adjusted to suit changing environmental conditions. Each detector includes built-in short-circuit isolation and dual tri-colour LEDs that provide 360° visibility of device status. The LEDs can be programmed for static or flashing red, amber, or green indications, offering clear and flexible visual feedback.

• Built in short circuit isolation

• New advanced Opal protocol allows mapping of the loop for precise fault location using isolators

• Tri colour LED offering red, green and amber colours

• Rotary decade address switches

• Pure white colour to complement modern buildings

• 100% mechanical and electrical backwards compatibility

• Base designed to ease installation and wiring