View Full Version : Apex Heater Control Issue

12/18/2012, 08:42 PM
I seem to have an issue. I just got two new 200w heaters (Eheim Jager). They have the turnable thermostat at the top. A red arrow + a blue dial. It's the first time I have had this kind of heater.

Well I plugged both heaters into my apex ports. This is the programming for both:

Fallback ON
If Temp < 79.0 Then ON
If Temp > 79.3 Then OFF
If Temp < 70.0 Then OFF

Only 1 heater was staying on though... I couldn't figure it out. I ended up moving the one heater a bit and fiddling with the dial and the light came on, but it could have been coincidence.

Do I have to set the manual thermostat on the heater to a higher temperature than my apex, in order to keep the Apex working? Does the internal heater take precedence over the Apex?

On a site note - do you keep the red arrow pointed center, or do you have to move both?

12/18/2012, 08:47 PM
Yes when your heaters have their own temp dial you must set them slightly higher than your highest programmed temp. This also acts as a bit of a fail safe in case your programming fails.

12/18/2012, 08:58 PM
Thank you bellis. Can you explain why this is? I was under the impression the Apex will control anything so long as it is plugged into the outlet (even if it had its own thermostat). I'll keep setting the temp higher until it seems to be working then.

12/18/2012, 09:30 PM
Think of it as two switches in a row... the Apex and the thermostat. Both "switches" have to be closed for the heater element to actually get power.

12/18/2012, 09:53 PM
To expand just a bit on what Russ said, suppose the t-stat on your heater was set to 75 and your tank temp is currently 79. The Apex applies power to your heater because you want the temp to be 80. But the heater 'thinks' the tank is already too warm because it's set to 75. So even though it has power, it doesn't turn on.

The solution is to set the heater t-stat at 81 or 82 if you want your tank to be 80. The Apex temp probe and the controller will turn the heater ON when told to and OFF at 80 but even if it doesn't, the heater's internal t-stat will turn it off at 81 (as an example) as a fail-safe.

12/19/2012, 12:24 AM
The Apex only turns the heater on and off according to the temp it gets from the temp probe, since the heaters themselves have their own built in temp control you have to set them just a bit higher than your Apex probe temp. If you buy heaters that are built to be controlled and come with no built in controller then you would not need to do this.

I kinda like having heaters with their own control so I can use it as back up protection from overheats.