Heat Detector

Heat Detectors are used mainly in kitchens and turbine compartments.  Those used in turbine compartments are color coded for various temperatures (at which the detector gives alarm/trip signal)

These are Bi-Metallic Switches and function based on temperature rise in the surrounding. They are preferred to smoke detectors in Kitchen as Kitchens produce smoke during cooking and used in Turbine compartments since the ambient temperature in Turbine compartments are very high and smoke detectors cannot function at theses high temperatures.

The Heat Detectors used in Kitchen are usually Rate of Rise detectors and operate at about 85 deg. C (my figure may not be accurate). The Heat Detectors used in the kitchen very similar to conventional smoke detectors except that there is no opening for the passage for smoke (as it functions based on heat and not on smoke).

The Heat Detectors employed in Turbine enclosures carry a color code, to specify the temperature at which the detectors change state (change of state of switch). Currently I do not have the information on the color code corresponding to the temperature at which the detector changes state. The Heat detector for each area in the turbine is selected based on the ambient temperature in which the detector is to be installed. As for example close to the Burner compartment the heat detector selected may be as high as one to operate at 350 deg C (as for example) and the near auxiliary compartment may operate at 120 deg C (as for example).

While replacing the detector, if the color is not clear in the detector refer to the drawing to find out the temperature class of the detector to be mounted.

The Heat Detector is tested using a Hot Air Blower which can generate sufficient heat for the detector to change state.

The number of Heat Detectors may also be connected to each zone just like smoke detectors and all the precautions and explanations provided above regarding the zone modules apply for heat detectors as well.

The power to the field devices is usually provided from the zone module. So, whenever a field device is to be replaced, if we pull out the zone module the power to the field will be last. However before pulling out the module check the cause & effect sheet.