Multi heater setup using Apex power bar

[JvC]

Hey all:

I wanted to share the setup I am currently running, which has worked out well - so far. I wanted to get any opinions on possible issues with this setup. OR Apex programming tips!

I switched from a multiple ink bird setup. Two heaters (output split) per inkbird). I had the temp set to 77. The 400 gallon system (300 DT / 100 sump) would swing from below 77 to above 78.

SpTmp = the temp in the sump
DTtemp = the temp in the overflow on the back of the display tank (before going to the basement sump).

This setup allows me to ramp up and down the use of multiple heaters. If the house is real cold, multiple heaters will be needed, but if the house is just dropping a little, the first (smaller of the 3) heaters can be enough by itself to heat the tank. It will be the only heater needed, If not, and the temp falls more, then more heaters turn on.

I have now gone to a 3 heater setup. 1 smaller, and 2 larger heaters. The heaters are each on an outlet in a 4 port power block from apex. And each has its own different programming.
Here is the programming:

Heater1:
Fallback OFF
If SpTmp < 77.9 Then ON
If SpTmp > 78.0 Then OFF
Defer 001:00 Then ON

Heater2:
Fallback OFF
If SpTmp < 77.7 Then ON
If SpTmp > 78.1 Then OFF
Defer 015:00 Then ON

Heater3:
Fallback OFF
If SpTmp < 77.5 Then ON
If SpTmp > 78.3 Then OFF
Defer 025:00 Then ON

I stil have 1 inkbird in the setup, with a lower temp, just incase all 3 fail or the apex fails, the inkbird with other backup heaters will kick on. So farm since setup, the extra inkbird has not been needed.

Thanks!

 

[therootcause]

Thanks for posting the code, can you help me understand the "defer" code? Is that the off lag following each "off" event? I have a similar temp swing, two heaters, one on an inkbird, and haven't taken the time to do what you have done.

 

[jkcoon]

I do the same with two large heaters - it keeps my temp within 4/10th of a degree all day

 

[JvC]

The DEFER command simply delays how long before the action is taken after the trigering condition is met. So, the tank will reach the temp to turn the heaters on, but the system will wait until turning the heater on.

I did this in an attempt to reduce the number of times the Apex will turn the outles on and off.

It seems, the tighter of a temperature window you want to maintain the more your equipment is going to need to turn on/off to maintain that temp.

I may adjust the DEFER statements, or the ON/OFF temps moving forward to dial this in. Obviosly, the more water volume the slower the temp swings.

 

[therootcause]

Do your heaters have built in thermostats, and if so, are you keeping that set point a degree or two above your APEX setting?