Best chiller program?

[ZachB]

What would be the best program to use for running a chiller?

I see there is a chiller drop down option in the configuration, but I want to make sure I don't cycle the chiller off and on without need. The chiller has it's own temperature setting and will turn itself off and on as appropriate (JBJ Arctica) so I just want to use the Apex as a failsafe.

Maybe have it come on and 77 and turn off at 75 (then set the chiller to run at 76?) - so if the chiller's thermostat ever broke it would not drop the tank too low and my temp will stay even at 76?

Thanks in advance!

 

[swearint]

I don't use a chiller, but I believe you would want to run it in a similar manner as a heater. Set the chiller thermostat just a bit lower than the desired temperature, and let the Apex perform the temperature control. Then if the Apex fails with the outlet ON, the chiller thermostat will act as backup and shut it itself OFF.

Todd

 

[RussM]

There are definitely 2 schools of thought on this topic. I prefer to do as Zach outlined... let a device having built-in temp control do the primary control of itself, and let the multi-purpose controller act as a safety net.

Let's use a chiller as an example... I'd set the chiller to operate as normally desired... let's say 78+/-0.5 degree. Then, I'd set the Apex or AC3 outlet to be normally ON, setting it to turn the outlet off if the temperature as measured by the Apex or AC3 goes below 77.0 or above 79.0. (Some adjustment may be necessary if the temp probe reading and the chiller thermostat don't match). This concept allows the Apex/AC3 to kill the chiller if either of the likely chiller failures occurs: overcooling of the tank or failure to cool adequately, i.e. to prevent it from running constantly if the chilling function fail.

This method also allows the Apex/AC3 to send an alarm if the temp goes outside the acceptable range... in this case, I'd have the alarm triggered anytime the Apex/AC3 shuts off the chiller.

Similar logic can be applied to heaters as well.... it works especially well for the common low-cost heaters which have simple thermostats rather than an actual temp controller built-in.

 

[bhammer]

Agree with them. Here is mine:

Fallback OFF
If Temp > 78.8 Then ON
If Temp < 78.4 Then OFF
If Temp > 81.5 Then OFF
If Temp < 77.5 Then Off
If FeedA 002 Then OFF

I am going to add the minimum off time in case of power failures so that if the power fails, the chiller will stay off for 5 minutes. This will keep from short cycling incase of power flickers and such.

 

[aquamanic]

I actually agree more with Todd on this one for the simple reason that the Apex can control my chiller far better than it can in terms of tolerance. My chiller can only go +/- 2 degrees. The Apex can go tenths of a degree. Maybe with a better chiller...:lmao:

 

[RussM]

Yep... it all depends on the particular situation. No "one-size-fits-all" in this hobby!

 

[ZachB]

Thanks for all the suggestions guys! I'll get something together this weekend and see how it works.