Heater ?

[catman78]

Have an issue with Heater Outlet. Seems like it s/b on, however it's not.

I'm using a therms plugged into Ranco,
plugged into outlet 6.
Ranco is set to 78 +-1

Neptune Temp probe enabled
Controller Temp says 78.8

Code:

Fallback ON
If Temp < 76.0 Then ON
If Temp > 80.0 Then OFF
If FeedA 000 Then OFF
If FeedB 000 Then OFF

Offset is -3 on probe

Any ideas

thanks

[RussM]

Question: what do you want to be the primary temp control? Apex or Ranco?

You need to have one doing the primary temp control and the other serving a backup. Right now they are conflicting.

[grcforce327]

...

[catman78]

The primary is the Ranco.
It's set to 78 with +-1 degree on/off.

Anything outside of my Apex Temps 76-80 would shut the outlet off, Right.

So if Temp according to apex is 78 out s/b on, it's not.

[catman78]

Is my statement correct?
I'm reading as On between 76 and 80

[RussM]

If Temp < 76.0 Then ON
If Temp > 80.0 Then OFF

This will not turn on the outlet until the temp drops below 76.0. So if the temp has not dropped that far, the outlet will not turn on. Once turned on, it will not turn off until the temp exceeds 80. Then, it will be off until the temp drops to < 76 again.

To use the Ranco as primary control and use the Apex as backup, use this:
Fallback ON
Set ON
If Temp > 79.5 Then OFF
I lowered the high cutoff threshold just a bit to 0.5 degrees above the 77-79 degree range of the Ranco.

The Set ON allows the outlet to normally be ON all of the time, letting the Ranco do its thing. The If Temp > 79.5 Then OFF line kills the outlet in case the temp goes too high (such as if the Ranco fails ON).

Also, you'll want to add these lines into your email alarm outlet:
If Temp > 79.5 Then OFF
If Temp < 76.5 Then OFF

[bazineta]

Probably worth noting as well that the above all presumes that the both the Ranco and the Apex are perfectly calibrated and thus read exactly the same temperature. This may or may not actually be the case, so you'll probably need to observe what each unit regards as the correct temperature and adjust accordingly if they disagree.

[RussM]

Probably worth noting as well that the above all presumes that the both the Ranco and the Apex are perfectly calibrated and thus read exactly the same temperature. This may or may not actually be the case, so you'll probably need to observe what each unit regards as the correct temperature and adjust accordingly if they disagree.+1 Well said!

[catman78]

Thanks again Russ. Was thinking I had a between statement... Should have looked at the manual.

[RussM]

Speaking of operating between two set points, another approach is to let the Apex operate over a slight wider range than the Ranco.

[Heater]
Fallback ON
If Temp > 76.5 Then ON
If Temp < 79.5 Then OFF

The drawback to this is that if the temp probe fails open (with a reading of ~20 degrees), the outlet would be shut off unnecessarily.

The way I suggested avoids that particular possibility.