The Apollo Orbis ORB-HT-51154-APO is an Intrinsically Safe (I.S.) heat detector with a flashing LED, suitable for a wide range of operating conditions, in which smoke detectors are unsuitable.
The Apollo Orbis ORB-HT-51154-APO has an open-web casing, which enables air to flow freely across a thermistor which measures the air temperature every 2 seconds. A microprocessor stores the temperature and compares it with pre-set values to determine if the alarm leven has been reached.
The Apollo Orbis ORB-HT-51154-APO is used in applications where smoke detectors can not be used. Smoke detectors are used whenever possible, since smoke detectors provides an earlier warning of fire than a heat detector. Heat detectors should only be used when there is a danger of nuisance alarms from smoke detectors.