Removal of Finnex heater controller?

Luucky13 · May 22, 2020

So I have a 500W Finnex titanium heater with the built in controller. I have it set up with my Apex. However recently, the heater itself started shutting down even when the Apex asked it to turn on. It turns on and off by itself. I even cranked the temp dial all the way up so that it would stay on, and now noticed that it just spins. I'm pretty sure the Finnex controller is pooched.

So my question is, can I just remove the Finnex controller all together and just solder the two wires together and just rely on the Apex to control the unit? Will the heater still work like normal if just hard wired without the controller?

Biglew11 · May 22, 2020

Yes this will work
Open up the controll housing, there should be the 2 wires coming in for a/c and 4 going to the heater element. 2 run the heating element and the other 2 should be for the thermostat. If you follow the traces on the board for the controller you should be able to see witch ac wire is switched on to turn heating element on. Jump those two wires and the heating element will be on all the time.

I'd recommend also consider connecting this to an external controller such as an inkbird https://aquarium.bulkreefsupply.com...vypdXvocd2zU&method=and&isort=score&view=grid

make sure you know switch wires run the heater and wich two are the thermostat.

Luucky13 · May 22, 2020

Thanks for the reply! I will open it up and check it out.

Luucky13 · May 22, 2020

I'm usually pretty good an this stuff. But now i'm confused. Can I just remove the controller all together and connect the white and black wires? Then one of the leads from the thermostat to either the black or white?

Biglew11 · May 22, 2020

You can remove the whole controller, then connect the 2 white together then the 2 blacks together and just leave the 2 red wires disconnected. This will leave the heater on all the time, so I would connect to an external controller such as inkbird.

Bulk reef supply suggest to have external controller set to controll heat, and Apex set 1 to 2 degrees higher as the safety cut off.

I use the apex to controll the temp and the external controller set as the upper limit.