ITC 308 alarm keeps going off

Hi, my itc-308 heat alarm keeps going off. It was working just fine and then the alarm started going off with the AH flashing on the display. If I press a button the noise stops for a while, but eventually comes back on. I’ve unplugged it for a while, but that didn’t help. Alarm started as soon as I plugged it back in. The unit is in my greenhouse and temperatures are between 0-10 C right now, so nothing unusual, and AH was at default. I adjusted the AH level a little, but that did nothing

Please check if the current temperature reading is correct?
If correct, please check if the AH setting is correct?
The AH and AL means, when the temperature reaches/ above AH, or reaches/ below AL, it will alarm.
Please note that if the current temperature reaches or exceeds the AH value, it will trigger an alarm.
If you don’t need the AH alarm, please increase the AH value.
For example, if the current reading is 10 degrees, please set AH=20

The temperature reading is near accurate, but it seems to wander a little. The AH setting is at 120 degrees so that’s not the issue

Actually, I just tried it again and the current temperature was accurate for a minute and then it started to climb. It eventually hovered around 110C (real temp is about 7C right now), and so it didn’t trip the alarm. So I think you’re right that the temperature sensor is the culprit. Any thoughts on how to address it?

Please check whether the ITC-308 probe is intact?
Please clean the probe and cable, then use a hairdryer to dry the entire unit for a while, then test the probe in the air temperature, can it read correctly?

Hi. I just tried this. After cleaning and drying, I plugged it back in. It read a little high for about 5 minutes, and then the temp started jumping all over the place again. Then it stabilized at close to actual for a minute, then back to jumping around wildly. Any follow up consideration?

Thank you

ITC-308 has a 1-year warranty. If it is under warranty, please email for after-sales service.