Finnex HC-810 Controller: Is it defective?

pinocchio · Apr 5, 2023

Starting yesterday the alarm on my Finnex controller started going off. I have my Min set to 67 and Max set to 90. The temp was 78 and the alarm wouldn't stop. The sensor was near the top of the water in the sump, so I moved it lower and I also I tried restarting the controller, all to no avail. The only thing that would turn it off was to lower the temp from 78 to 77. If I tried to go back up to 78 the alarm would sound again.

I woke up this morning to the alarm AGAIN. Only way to fix it was to change the temp from 77 to 76. Anyone have any idea what is going on here? Is my controller broken? Is it the heater?

Each time the light indicating the heater was on was lit up if that helps.

MnFish1 · Apr 6, 2023

pinocchio said:
Starting yesterday the alarm on my Finnex controller started going off. I have my Min set to 67 and Max set to 90. The temp was 78 and the alarm wouldn't stop. The sensor was near the top of the water in the sump, so I moved it lower and I also I tried restarting the controller, all to no avail. The only thing that would turn it off was to lower the temp from 78 to 77. If I tried to go back up to 78 the alarm would sound again.

I woke up this morning to the alarm AGAIN. Only way to fix it was to change the temp from 77 to 76. Anyone have any idea what is going on here? Is my controller broken? Is it the heater?

Each time the light indicating the heater was on was lit up if that helps.

IF your lower alarm limit is 67 (rather than 76 - didn't know if you made a type), there has to be either a problem with where you have your 'sensor' - or with the heater. However - before giving up Check out the manual - and re-calibrate the heater - using the Ca button. Second I would measure the temp in your tank using an independent thermometer - (any plain thermometer) - to make sure the alarm is not somehow correct (which I would doubt). IMHO - if calibration is not the problem - and position is not the problem - you will need a new heater. I would also double-check the settings