» Overtemperature Alarm Units: type OTM1, OTM2 & OTM8

The OTM range of electronic Overtemperature Alarm Units provides security against overtemperature damage in Computer Centres and other critical areas which can be caused by failure of the air conditioning or cooling systems. Excessive temperatures can cause computer hardware to malfunction or to operate incorrectly. The single alarm unit , the OTM1 comprises a temperature sensor rated for temperature band 0 to 30° C located in the monitored area and connected to the controller, possibly remote. Immediately the adjustable temperature module senses an overtemperature condition the light on the OTM activates, and remains on while the sensor continues to be in alarm. The horn also sounds and can be muted by pressing the mute button, and then automatically resets. Two sets of N/V output contacts are provided rated 240V AC 3amp for remote alarm, autodial or shutdown purposes.


The OTM2 Overtemperature Alarm Unit is linked to two temperature sensors and can be used either as a low/high temperature alarm, or as a two-zone temperature alarm, or as a two-stage overtemperature alarm, by setting of the sensor controls. Operation is otherwise as the OTM1 but the unit is provided with two individual sets of output N/V contacts, one for each stage of Temperature Alarm to provide for computer shutdown / system control / separate output signalling requirements.


The OTM8 Temperature/Overtemperature Alarm Unit can be linked up to eight adjustable temperature sensors which can be configured to provide stages or zoning of temperature/overtemperature alarm. System can also include stages of humidity alarm from remote humidistats (rated 30-90% RH ). When the pre-set limit is breached, the appropriate zone light on the OTM 8 activates. The light remains on all the time that the sensor remains in alarm. The horn sounds and can be muted by pressing the mute button. A common alarm relay with volt-free contacts (rated at 28V DC 1 amp) is fitted as standard and energises on any alarm way activating. Should individual output alarm signals be required, each alarm can be fitted with an optional output relay with volt free contacts (rated 28V DC 1 amp) to repeat to a Wayscale Multizone Annunciator or to indicate individual alarms to a BMS System.  The OTM 2 and the OTM8 are frequently used to provide automatic shutdown facilities for computer hardware via the emergency stop circuit of the computer power supply. In these cases we recommend the fitting of a key override switch to the enable the manual override of the shutdown circuit .