Heating Questions

JustForFun · Sep 4, 2020

Hello, all. I have questions about heating. Not sure if this question falls under the controllers forum or here. The Neptune Apex controller gives me a level of control i never thought possible.

So I'm wondering if there are any benefits to having a temperature swing higher than 1 degree since we are now able to calibrate changes so low. I also didn't expect the titanium heaters to be so effective. I have two 600w heating units in 240 gallons of water volume and ive already shut down one of them because the water heats up so quickly. Should I lower my temp range LESS than half a degree? What are the benefits of a samll temp swing? (We already know the horrors of large temp swings). How fast is too fast in a small temp swing? Should I calibrate my heaters to only change a few tenths of a degree? Thanks in advance.

Fred2482 · Sep 4, 2020

Less than 1 degree is great! I found that when I tried to tune it under 1 degree I got to many on/off toggles that did not seem correlate with my temp calibrator (probe swings bigger than temp calibrator). Ultimately I took the heaters off the apex and placed them on an 3rd party temp controller to reduce the amount of on/off toggles. I set a 1 degree variance on this controller to reduce the amount of on/off toggles as well as allow the timing of the probes to accurately relay info to controller.

Biglew11 · Sep 4, 2020

I run mine at 1 degree. Brs has a video and they were running .1 and they wore out the outlet on the energy bar.

Galvano · Sep 5, 2020

According to Neptune System's Energy Bar webpage only the EB8 model is equipped with SSRs in addition to mechanic relays the other models EB4 and EB6 are solely using.

These mechanically toggled "120V AC Outlets all switched with relays rated for millions of cycles" would perform half a million cycles within a year when switching back and forth once a minute.

Now let's take a common DS18B20 thermal probe, which with a maximum resolution of 12 bits reports minimum temperature increments of .0625°C/.1125°F. A .1°F hysteresis means here an on-off cycle with any slightest temperature deviation from the target value. Accordingly - without an additional time delay strategy - I see my SSR-controlled heater doing about 10 switching cycles a minute while keeping temperature within that .0625°C/.1125°F range. No wonder with such continuous strain mechanic relays wear out very fast, which is why you'd have to use SSRs.

Or increase the hysteresis interval to .2°F. That means temperature has to move two steps away from the target to toggle output, and with now about 10 minutes long on-off cycles the problem lessens even with a mechanic relay.