Description
Alarm relay
The alarm circuit has voltage free relay contacts and are rated up to 2A @ 125V ac (RMS) load.
The internal supply to the relay is obtained from the transformer via a 20mm 1A fuse. These are connected to the Live and Neutral supply and therefore the relay and LED can only energise when there is an over-temperature condition or sensor fault, as long as the supply is present.
Over temperature protection
When a heatsink temperature of above 90ºC is detected by the sensor, the alarms relay changes state and the LED pulses rapidly. The power to the load will be disconnected and will not return until the temperature drops to 85ºC.
Temperature sensor loss
LED status changes to ON/OFF (fast pulsing) if the sensor fails.